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Ammonia volatilization losses from manure during and following application to land Cha, Daniel 1986

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AMMONIA VOLATILIZATION LOSSES FROM MANURE DURING AND FOLLOWING APPLICATION TO LAND by DANIEL CHA B.Sc. (Agr. Eng.), M c G i l l U n i v e r s i t y , 1984. A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE in FACULTY OF GRADUATE STUDIES (DEPARTMENT OF BIO-RESOURCE ENGINEERING) We accept t h i s t h e s i s as conforming to the r e q u i r e d standard THE UNIVERSITY OF BRITISH COLUMBIA August, 1986 © D a n i e l Cha, 1986 In presenting t h i s thesis i n p a r t i a l f u l f i l m e n t of the requirements for an advanced degree at the University of B r i t i s h Columbia, I agree that the Library s h a l l make i t f r e e l y available for reference and study. I further agree that permission for extensive copying of t h i s thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. I t i s understood that copying or publication of t h i s thesis for f i n a n c i a l gain s h a l l not be allowed without my written permission. Department Of Bio-Resource Engineering The University of B r i t i s h Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 Date October 10, 1986. i i ABSTRACT . V o l a t i l i z a t i o n l o s s of ammonia d u r i n g and f o l l o w i n g land a p p l i c a t i o n of l i q u i d manure was measured i n s i x experiments c a r r i e d out on three d i f f e r e n t farms i n B r i t i s h Columbia. Ammonia l o s s d u r i n g a p p l i c a t i o n was determined by comparing the ammonia content of manure i n the tanker and the ammonia content of manure i n the c o l l e c t i o n t r a y s on the f i e l d . Ammonia v o l a t i l i z a t i o n a f t e r s p r e a d i n g was determined by measuring the ammoniacal-N c o n c e n t r a t i o n of s o i l c ores immediately f o l l o w i n g spreading, and a t day 1, day 2 and day 5. The percentage of ammonia v o l a t i l i z e d d u r i n g the a p p l i c a t i o n of manure v a r i e d from 4.0 t o 12.0% i n summer depending on the spreading method (h i g h or low s p r a y ) . Losses from the high spray system were s i g n i f i c a n t l y h i g h e r than from the low spray system. The percentage of ammonia l o s t d u r i n g a p p l i c a t i o n of manure d u r i n g summer was always g r e a t e r than d u r i n g w i n t e r . Over the temperature range of 4 to 25 °C, each i n c r e a s e of 10 °C r e s u l t e d i n an i n c r e a s e i n ammonia l o s s of 2.4%. i i i The percentage of ammonia l o s s d u r i n g the f i r s t 24 hours a f t e r a p p l i c a t i o n was a f u n c t i o n of temperature, manure type, s o i l moisture co n t e n t , and manure a p p l i c a t i o n r a t e . The percentage of ammonia l o s t a f t e r a p p l i c a t i o n d u r i n g summer was always g r e a t e r than the percentage l o s t d u r i n g w i n t e r . The percentage of ammonia l o s t from d a i r y manure 24 hours a f t e r a p p l i c a t i o n was higher than t h a t from swine manure by a f a c t o r of about 2. An i n c r e a s e i n s o i l moisture content by a f a c t o r of two i n c r e a s e d the percentage of ammonia l o s s i n 24 hours by approximately the same f a c t o r . A much t h i n n e r manure cover at 52 t h a - 1 r e s u l t e d i n a g r e a t e r percentage of ammonia l o s s (54.7%) i n 24 hours than that of 138 t ha' 1 (42.0%). The percentage of ammonia l o s t 48 hours a f t e r a p p l i c a t i o n v a r i e d from 43.3 to 84.8%. The d i f f e r e n c e s i n l o s s are a t t r i b u t e d to temperature, manure type, and manure a p p l i c a t i o n r a t e . The percentage of ammonia l o s t 5 days a f t e r a p p l i c a t i o n v a r i e d from 50.0 to 93.9%. Temperature and a 30 cm snow cover d u r i n g the winter study were the primary f a c t o r s r e s p o n s i b l e f o r the d i f f e r e n c e s i n ammonia l o s s a f t e r 5 days. i v TABLE OF CONTENTS ABSTRACT i i TABLE OF CONTENTS i v LIST OF TABLES V LIST OF FIGURES v i i ACKNOWLEDGEMENTS ix I. INTRODUCTION 1 I I . SPECIFIC RESEARCH OBJECTIVES 3 I I I . LITERATURE REVIEW 4 A. L i v e s t o c k Waste Management - Land D i s p o s a l ... 4 B. V o l a t i l i z a t i o n Loss of Ammonia 5 C. F a c t o r s A f f e c t i n g V o l a t i l i z a t i o n Loss of Ammonia 8 IV. MATERIALS AND METHODS 16 A. Experimental S i t e s 16 B. Experimental Design and Sampling Procedure ... 16 C. A n a l y t i c a l Technique 24 V. RESULTS AND DISCUSSION 26 A. Ammonia N i t r o g e n Loss During A p p l i c a t i o n 26 B. A n a l y t i c a l Method Comparison f o r S o i l Ammonia A n a l y s i s 35 C. Ammonia N i t r o g e n Loss F o l l o w i n g A p p l i c a t i o n .. 36 VI . SUMMARY 71 V I I . CONCLUSIONS 73 VIII RECOMENDATIONS 75 LITERATURE CITED 76 APPENDIX A 79 APPENDIX B 81 APPENDIX C . 88 LIST OF TABLES Table T i t l e page 1 Name, l o c a t i o n , and manure type of the 17 experimental s i t e s and the d u r a t i o n of experiments 2 Topography, s o i l , and v e g e t a t i o n of the 18 experimental s i t e s 3 Environmental c o n d i t i o n s and manure 27 c h a r a c t e r i s t i c s f o r the summer experiments 4 Environmental c o n d i t i o n s and manure 27 c h a r a c t e r i s t i c s f o r the winter experiments 5 Percent ammonia l o s s d u r i n g a p p l i c a t i o n 29 in summer 6 percent ammonia l o s s d u r i n g a p p l i c a t i o n 30 in winter 7 Background pH, moisture, ammonia, TKN, and 37 n i t r a t e c o n c e n t r a t i o n of s o i l b efore manure a p p l i c a t i o n i n summer ( s o i l depth=0.5 cm) 8 Background pH, moisture, ammonia, TKN, and 38 n i t r a t e c o n c e n t r a t i o n of s o i l b efore manure a p p l i c a t i o n i n winter ( s o i l depth=0.5 cm) 9 E f f e c t of temperature on the l o s s of 49 ammonia from s u r f a c e a p p l i e d manure a f t e r 24 hours 10 E f f e c t of s o i l moisture content on 55 percent ammonia l o s s from swine manure i n 24 hours 11 E f f e c t of manure s o l i d s c o n c e n t r a t i o n 59 on the l o s s of ammonia from s u r f a c e a p p l i e d manure 12 Manure a p p l i c a t i o n r a t e 59 13 S o i l pH d u r i n g summer over a 5 day sampling 63 p e r i o d 14 S o i l pH d u r i n g winter over a 5 day sampling 63 p e r i o d v i Changes in.ammonia, TKN, and n i t r a t e c o n c e n t r a t i o n i n s o i l over 5 days f o l l o w i n g an a p p l i c a t i o n of l i q u i d manure i n summer Changes i n ammonia, TKN, and n i t r a t e c o n c e n t r a t i o n i n s o i l over 5 days f o l l o w i n g an a p p l i c a t i o n of l i q u i d manure i n winter Comparison of c a l c u l a t e d and measured v a l u e s of ammonia l o s s i n 5 days i n summer Comparison of c a l c u l a t e d and measured v a l u e s of ammonia l o s s i n 5 days i n winter v i i LIST OF FIGURES F i g u r e T i t l e page 1 A vacuum tanker at a manure p i t 19 2 C o l l e c t i o n t r a y s on the f i e l d 21 3 Lay-out of the sampling t r a y s 22 4 E f f e c t of ambient temperature on the 32 percent ammonia l o s s d u r i n g manure a p p l i c a t i o n 5 P a r t i a l p r e ssure of ammonia over an 34 aqueous s o l u t i o n (5% ammonia s o l u t i o n ) at v a r i o u s temperature 6 Changes i n ammonia c o n c e n t r a t i o n i n s o i l 39 with time f o l l o w i n g an a p p l i c a t i o n of d a i r y manure at farm A 7 Changes i n ammonia c o n c e n t r a t i o n i n s o i l 40 with time f o l l o w i n g an a p p l i c a t i o n of swine manure at farm A 8 Changes i n ammonia c o n c e n t r a t i o n i n s o i l 41 with time f o l l o w i n g an a p p l i c a t i o n of swine manure at farm B 9 Changes i n ammonia c o n c e n t r a t i o n i n s o i l 42 with time f o l l o w i n g an a p p l i c a t i o n of d a i r y manure at farm C 10 Percent ammonia l o s s from swine manure 44 f o l l o w i n g a p p l i c a t i o n at farm A 11 Percent ammonia l o s s from swine manure 45 f o l l o w i n g a p p l i c a t i o n a t farm B 12 Percent ammonia l o s s from d a i r y manure 46 f o l l o w i n g a p p l i c a t i o n a t farm A 13 Percent ammonia l o s s from d a i r y manure 47 f o l l o w i n g a p p l i c a t i o n at farm C 14 E f f e c t of manure ponding on the l o s s 52 ammonia from s u r f a c e a p p l i e d swine manure 15 Comparison of percent ammonia l o s s from 57 d a i r y and swine manure at farm A v i i i E f f e c t of manure a p p l i c a t i o n r a t e on the r a t e of ammonia l o s s from s u r f a c e a p p l i e d manure Percentage of ammonia i n s o l u t i o n at e q u i l i b r i u m at v a r i o u s pH i x ACKNOWLEDGEMENT I wish to express my s i n c e r e thanks and g r a t i t u d e to my s u p e r v i s o r Dr. Ross B u l l e y f o r h i s constant advice and encouragement. S i n c e r e a p p r e c i a t i o n i s a l s o expressed to Dr. S.T. Chieng and Dr. A. Bomke f o r t h e i r c o n s t r u c t i v e c r i t i c i s m s and h e l p f u l s u g g e s t i o n s . I would a l s o l i k e to thank the e n t i r e t e c h n i c a l s t a f f and the gradute students of the Bio-Resource E n g i n e e r i n g Department f o r t h e i r e n t h u s i a s t i c support and a s s i s t a n c e . F i n a l l y , s p e c i a l thanks to my wif e , my paren t s , and my brother f o r t h e i r moral support. 1 I. INTRODUCTION A p p l i c a t i o n of animal waste to crop land i s eco n o m i c a l l y the best e s t a b l i s h e d method of waste management because the n i t r o g e n ( N ) , phosphorus(P), and potassium(K) content of the waste can be u t i l i z e d as p l a n t n u t r i e n t s . However, one of the most important concerns r e l a t e d to u t i l i z a t i o n and d i s p o s a l of farm manure i s the f a c t t h a t n i t r o g e n i n the ammonia form i s r e a d i l y l o s t through v o l a t i l i z a t i o n . T h i s l o s s r e s u l t s i n a r e d u c t i o n i n the f e r t i l i z e r value of manure and an i n c r e a s e i n the p o t e n t i a l f o r environmental problems. Furthermore, s i n c e ammonia v o l a t i l i z a t i o n occurs immediately a f t e r the land a p p l i c a t i o n of manure and a s i g n i f i c a n t amount of N can be l o s t , the q u a n t i t y of n i t r o g e n i n manure which w i l l f i n a l l y became a v a i l a b l e to p l a n t s i s d i f f i c u l t to es t i m a t e . In order to best manage and u t i l i z e manure, i t i s necessary to know the q u a n t i t i e s of n u t r i e n t s i n the manure and any changes i n these n u t r i e n t s d u r i n g h a n d l i n g . Two of the most c r u c i a l p e r i o d s concerning n i t r o g e n c o n s e r v a t i o n are 1) d u r i n g the a p p l i c a t i o n of manure and 2) f o l l o w i n g a p p l i c a t i o n and before i n c o r p o r a t i o n i n t o the s o i l . There are very few r e p o r t s on the l o s s of ammonia from manure durin g a p p l i c a t i o n . B u l l e y and Holbek(l982) 2 re p o r t e d that between 4 and 9% of the n i t r o g e n i n d a i r y manure was l o s t d u r i n g a p p l i c a t i o n with a sid e d e l i v e r y f l a i l spreader. Pote et a l (1980) suggested that d u r i n g s p r i n k l e r i r r i g a t i o n , ammonia l o s s w i l l not exceed 8% f o r low pH (7 to 8) manure; however, at pH 10.5, l o s s of 30 to 60% ammonia n i t r o g e n was p r e d i c t e d . Many s t u d i e s i n d i c a t e that a l a r g e f r a c t i o n of N i n manure i s l o s t by v o l a t i l i z a t i o n of ammonia f o l l o w i n g the manure a p p l i c a t i o n and before crops are p l a n t e d (Lauer et a l , 1976; Beauchamp et a l , 1978, 1982; Reddy et a l , 1979). Lauer et a l . (1976) showed that up to 90% of the ammonia content i n s o l i d d a i r y c a t t l e manure may be l o s t i n 5 days f o l l o w i n g s u r f a c e a p p l i c a t i o n . Beauchamp et a l ( l 9 8 2 ) i n d i c a t e d that only 24 to 33% of the a p p l i e d ammoniacal-N in l i q u i d d a i r y manure may be l o s t a f t e r 6 or 7 days i n May. I t i s q u i t e apparent that many f a c t o r s such as manure and s o i l pH, temperature, manure s o l i d s c o n c e n t r a t i o n , s o i l type, and v e g e t a t i v e cover have str o n g e f f e c t s on ammonia l o s s from manure (Reddy et a l , 1979, Donovan and Logan, 1983). The o b j e c t i v e of t h i s t h e s i s i s to measure the changes i n n i t r o g e n content of manure d u r i n g and f o l l o w i n g i t s a p p l i c a t i o n to a grass c r o p under f i e l d c o n d i t i o n s . I I . SPECIFIC RESEARCH OBJECTIVES To determine the e f f e c t of s e l e c t e d manure a p p l i c a t i o n methods on v o l a t i l i z a t i o n l o s s e s of ammonia d u r i n g spreading. To determine the e f f e c t of s e l e c t e d v a r i a b l e s ( i e . pH, temperature, s o i l moisture content, manure a p p l i c a t i o n r a t e , manure s o l i d s c o n c e n t r a t i o n ) on the l o s s of ammonia from f i e l d spread manure f o r up to f i v e days a f t e r spreading. 4 I I I . LITERATURE REVIEW A. L i v e s t o c k Waste Management - Land D i s p o s a l It has been estimated that about 6 m i l l i o n wet tonnes of wastes are produced a n n u a l l y i n B r i t i s h Columbia from the l i v e s t o c k and p o u l t r y i n d u s t r y (BCMAF, 1983). Regardless of the h a n d l i n g and treatment systems used, there w i l l s t i l l be l a r g e volumes of e i t h e r s o l i d or l i q u i d wastes that r e q u i r e d i s p o s a l . A r e l a t i v e l y simple yet p o s i t i v e method i s to u t i l i z e the waste f o r i t s n u t r i e n t content by r e c y c l i n g i t back to the crops through a p p l i c a t i o n to the s o i l . A l s o i n c r e a s e s i n i n o r g a n i c f e r t i l i z e r c o s t s have s t i m u l a t e d an i n c r e a s e i n the use of animal waste as a p l a n t n u t r i e n t source. Methods that are a v a i l a b l e f o r a p p l y i n g l i v e s t o c k wastes to land i n c l u d e : s u r f a c e a p p l i c a t i o n , s u r f a c e a p p l i c a t i o n with immediate plow-down, or i n j e c t i o n i n t o the s o i l . Whenever p o s s i b l e , manure should be plowed or i n j e c t e d i n t o the s o i l (Sutton, 1981). T h i s w i l l h e l p to c o n t r o l odors and a l s o reduce the l o s s of n i t r o g e n caused by v o l a t i l i z a t i o n . 5 B. V o l a t i l i z a t i o n Loss of Ammonia Fresh animal waste c o n t a i n s from 0.1 to 1.0% ammonia-N (Hoff et a l , 1981). V o l a t i l e l o s s e s of ammonia occur when manure i s exposed to a i r movement i n animal p r o d u c t i o n f a c i l i t i e s and i n the f i e l d d u r i n g and a f t e r s p r e a d i n g . Ammonia v o l a t i l i z a t i o n from animal f a c i l i t i e s or from land a p p l i c a t i o n s i t e s can c o n t r i b u t e s i g n i f i c a n t q u a n t i t i e s of ammonia to the atmosphere and cause a i r and water p o l l u t i o n . D i r e c t a b s o r p t i o n of the atmospheric ammonia by lakes and streams c o u l d c o n t r i b u t e to t h e i r e u t r o p h i c a t i o n ( E l l i o t et a l . , 1971; Luebs et al.,1973; Denmead et a l . , 1974). Hutchinson and V i e t s (1969) demonstrated that a lake near a beef f e e d l o t absorbed enough ammonia per year from the a i r to r a i s e i t s N content by 0.6 mg/1. However, Lauer et a l . (1976) s t a t e d that the m a j o r i t y of ammonia v o l a t i l i z e d moves away from the immediate v i c i n i t y , and the d i s p e r s a l and d i l u t i o n of ammonia i n the atmosphere i s q u i t e r a p i d . Lueb et a l . (1973) found ammonia i n the a i r 0.8 km downwind from a 600-cow d a i r y f a c i l i t y to be n e a r l y at the background l e v e l of the surrounding a r e a . The most s e r i o u s consequence of ammonia v o l a t i l i z a t i o n from manure s l u r r y i s the d i s p e r s a l of N 6 that c o u l d have been u t i l i z e d as a f e r t i l i z e r f o r c r o p p r o d u c t i o n . V o l a t i l i z a t i o n l o s s of ammonia from s t o r e d and s u r f a c e a p p l i e d s l u r r y must be reduced to improve the economic value of l i q u i d manure as a f e r t i l i z e r . Sutton (1981) r e p o r t e d l o s s e s of 20 to 40% of ammonia-N from manure storage f a c i l i t i e s (deep p i t and earthen storage p i t ) . Higher l o s s e s of ammonia-N of 70 to 90% were r e p o r t e d from manure treatment systems such as lagoons and o x i d a t i o n d i t c h e s where the manure was exposed to the a i r f o r an extended amount of time. Pote et a l . (1980) examined l o s s e s of ammonia n i t r o g e n d u r i n g the a p p l i c a t i o n of l i q u i d manure with a s p r i n k l e r i r r i g a t i o n system. The degree of l o s s and the r a t e s of l o s s e s were a f u n c t i o n of pH, ambient temperature, and d r o p l e t s i z e . They s t a t e d t h a t when pH i s low (7 to 8) as i n most animal manures, the ammonia-N l o s s w i l l not exceed 8%. The statement was supported by B u l l e y and Holbek (1982) who r e p o r t e d l o s s e s of 4 to 9% d u r i n g the a p p l i c a t i o n of d a i r y manure (pH 7.7) with a s i d e d e l i v e r y f l a i l spreader. Pote et a l . (1980), however, p r e d i c t e d a l o s s of 30 to 60% at pH 10.5. In a d d i t i o n , they found that i n c r e a s e s i n ambient temperature caused an almost l i n e a r i n c r e a s e i n ammonia l o s s . They a l s o r e p o r t e d that d r o p l e t diameter, when halved, t r i p l e d ammonia l o s s e s at pH 8. 7 Many s t u d i e s i n d i c a t e that a l a r g e f r a c t i o n of N i n a p p l i e d manure i s l o s t by v o l a t i l i z a t i o n of ammonia a f t e r spreading (Lauer et a l . , 1976; Crane et a l . , 1981; Hoff et a l . , 1981; Donovan and Logan, 1983). Although ammonia-N l o s s e s have been r e p o r t e d to be as low as 24 to 33% of a p p l i e d d a i r y manure n i t r o g e n a f t e r 6 days (Beauchamp et a l . , 1982), l o s s e s of more than 80% w i t h i n 3 days were r e p o r t e d d u r i n g a greenhouse study using swine s l u r r y (Hoff et a l . , 1981). Thus, N l o s s e s can be c o n s i d e r a b l e i f manure c h a r a c t e r s t i c s and environmental c o n d i t i o n s are f a v o u r a b l e . Crane et a l . (1981) repo r t e d t h a t ammonia l o s s e s were between 75 and 100% over a 5-day p e r i o d f o l l o w i n g a p p l i c a t i o n of p o u l t r y manure at a temperature of 24 °C and a humidity of 70%. A m a j o r i t y of the ammonia con t a i n e d i n a manure s l u r r y may be l o s t i n a short p e r i o d f o l l o w i n g s u r f a c e a p p l i c a t i o n . Lauer et a l . (1976) i n d i c a t e d t h a t 50% of the ammonia content i n d a i r y manure can be l o s t w i t h i n 1 to 2 days a f t e r s u r f a c e a p p l i c a t i o n . 8 C. F a c t o r s A f f e c t i n g V o l a t i l i z a t i o n Loss of Ammonia I t i s q u i t e apparent that a number of manure, s o i l and environmental f a c t o r s have strong e f f e c t on ammonia l o s s from manure. A d i s c u s s i o n of some of the dominant f a c t o r s w i l l h e lp i n determining the measures to be taken to reduce such l o s s e s . 1. Manure and s o i l pH 2. Temperature 3. Manure i n c o r p o r a t i o n 4. A i r movement 5. S o i l moisture content 6. I n f l u e n c e of other f a c t o r s 1. Manure and S o i l pH Many s t u d i e s have i n d i c a t e d the r e l a t i o n s h i p between pH and ammonia v o l a t i l i z a t i o n ( Peters and Reddal, 1973; M i l l s et a l . , 1974; Reddy et a l . , 1979; Hoff et a l . , 1981; Crane et a l . , 1983; Donovan and Logan, 1983). During ammonia v o l a t i l i z a t i o n , the f o l l o w i n g p h y s i c o - c h e m i c a l process occurs (Reddy et a l . , 1979). The d i s s o c i a t i o n of ammonia-N i s given as: NH3 + H20 =^r NH* + 0H~ T h i s r e a c t i o n i s h i g h l y pH dependent. At a l k a l i n e pH, ammonia, which i s h i g h l y s u s c e p t i b l e to v o l a t i l i z a t i o n , 9 predominates while at n e u t r a l or a c i d i c pH, the ammonia-N i s mainly i n i o n i c form. M i l l s et a l (1974) r e p o r t e d that about 10% of added f e r t i l i z e r ammonia-N was l o s t as ammonia gas when the s o i l pH was i n the range of 7.0-7.5, over a one week p e r i o d , whereas about 47% of added ammonia-N was l o s t at pH of 7.5-8.0, and 63% at pH 8.0-8.5 du r i n g the same p e r i o d . Donovan and Logan (1983) r e p o r t e d that 20, 21, and 24% of n i t r o g e n a p p l i e d i n sewage sludge was v o l a t i l i z e d i n 24 hours f o r s o i l s with pH's of 5.1, 6.7 and 7.5 r e s p e c t i v e l y . On land areas r e c e i v i n g animal manure, ammonia v o l a t i l i z a t i o n l o s s e s are i n f l u e n c e d by the pH of both the s o i l and manure. Hoff et a l . (1981) r e p o r t e d that ammonia-N l o s s e s from broadcast swine manure v a r i e d s i g n i f i c a n t l y with s o i l and manure pH. Ne a r l y 65% of the a p p l i e d ammonia-N was v o l a t i l i z e d i n a 3.5-day p e r i o d when manure with a pH of 7.8 was a p p l i e d to the s o i l with a pH of 7.0, whereas only 14% of the a p p l i e d ammonia-N was v o l a t i l i z e d from the s o i l with a pH of 6.4 and a manure pH of 6.4 i n the same p e r i o d of time. Crane et a l . (1979) observed that the s o i l pH approached the pH found i n the f r e s h manure f o l l o w i n g the a p p l i c a t i o n of p o u l t r y manure. They suggested that i f manure i s spread on the s o i l s u r f a c e , the e f f e c t of s o i l 10 pH on ammonia l o s s becomes n e g l i g i b l e , and l o s s e s of ammonia are i n f l u e n c e d by the pH of the manure i t s e l f . 2. Temperature I n c r e a s i n g the temperature of soil-manure systems i n c r e a s e s the l o s s of ammonia through v o l a t i l i z a t i o n (Adriano et a l . , 1974; Steenhuis et a l . , 1976; Reddy et a l . , 1979; Donovan and Logan, 1983) The e f f e c t of temperature on ammonia v o l a t i l i z a t i o n from urea spread on s o i l was w e l l documented i n many o l d e r r e f e r e n c e s (Ernst and Massey, 1960; Wagner and Smith, 1958). E r n s t and Massey (1960) used temperatures of 7, 16, 24, and 32 °C to study the e f f e c t of temperature on the v o l a t i l i z a t i o n l o s s e s of ammonia from urea on a s o i l with pH 6.5. They r e p o r t e d a s i g n i f i c a n t i n c r e a s e i n ammonia v o l a t i l i z a t i o n f o r each temperature i n c r e a s e . Wagner and Smith (1958) compared ammonia v o l a t i l i z a t i o n l o s s e s from urea at temperatures of 10 and 25 °C. For the f i r s t two weeks a f t e r the a d d i t i o n of urea, they r e p o r t e d that ammonia l o s s e s were s i g n i f i c a n t l y higher at 25 °C. As evidence that ammonia v o l a t i l i z a t i o n i s temperature dependent, E l l i o t et a l . (1971) r e p o r t e d much higher ammonia l o s s e s from a f e e d l o t i n the s p r i n g than wi n t e r . Steenhuis et a l . (1976) suggested the c o n v e r s i o n of urea to ammonia, which i s temperature dependent, may be 11 the l i m i t i n g f a c t o r of ammonia v o l a t i l i z a t i o n f o l l o w i n g winter s p r e a d i n g . At lower temperatures, a l a r g e amount of manure N i s i n the more s t a b l e urea form (Steenhuis et a l , 1976). S e v e r a l s t u d i e s have i n d i c a t e d that the ammonia f l u x from manure a p p l i e d to the s o i l s u r f a c e f o l l o w e d a d i u r n a l p a t t e r n (Denmead et a l . , 1974; Beauchamp et a l . , 1978, 1982; Harper et a l . , 1983). Beauchamp et a l . (1978, 1982) re p o r t e d that the d i u r n a l ammonia f l u x was very c l o s e l y r e l a t e d to ambient temperature with i t s maxima o c c u r r i n g s h o r t l y a f t e r midday and minima o c c u r r i n g d u r i n g the e a r l y morning hours. 3. Manure I n c o r p o r a t i o n Fenn and K i s s e l (1976) r e p o r t e d that the i n c o r p o r a t i o n of the ammonium compounds i n t o the s o i l reduced ammonia l o s s e s , and the degree of r e d u c t i o n i n c r e a s e d with the depth of i n c o r p o r a t i o n . Donovan and Logan (1983) a l s o r e p o r t e d that ammonia v o l a t i l i z a t i o n decreased when sludge was i n c o r p o r a t e d , and the magnitude of the l o s s i s determined by the time l a g between a p p l i c a t i o n and i n c o r p o r a t i o n . They r e p o r t e d that f o r sludge i n c o r p o r a t e d at 0.25, 1, 3, 6, and 12 hours a f t e r a p p l i c a t i o n , ammonia-N v o l a t i l i z e d i n 24 hours was was 3, 4, 6, 14, and 26% of the ammonia-N a p p l i e d , r e s p e c t i v e l y . 12 The r e s u l t s i n d i c a t e that there i s an o p p o r t u n i t y to conserve the ammonia-N i f the sludge i s i n c o r p o r a t e d as soon a f t e r a p p l i c a t i o n as p o s s i b l e . 4. A i r Movement St u d i e s have i n d i c a t e d that v o l a t i l i z a t i o n of ammonia i n c r e a s e s with i n c r e a s i n g a i r movement (Watkins et a l . , 1972; Steenhuis., 1976; Vlek and Stumpe., 1978). Steenhuis et a l . (1976) r e p o r t e d that i n c r e a s i n g the a i r flow r a t e by a f a c t o r of two i n c r e a s e d the r a t e of ammonia l o s s by approximately the same f a c t o r . They recommended spreading manure du r i n g p e r i o d s of low a i r turbu l e n c e minimizes v o l a t i l i z a t i o n l o s s e s . Watkins et a l . (1972) showed that at the a i r flow r a t e of 100 to 3000 mL min~ 1 ammonia l o s s e s were n e a r l y p r o p o r t i o n a l to the l o g of flow r a t e . They r e p o r t e d that these flow r a t e s corresponded to c a l c u l a t e d average a i r v e l o c i t i e s ranging from 0.0004 to 0.01 km h" 1 A subsequent experiment i n d i c a t e d that a f u r t h e r r a t e i n c r e a s e to 7000 mL min" 1 had l i t t l e a d d i t i o n a l e f f e c t on v o l a t i l i z a t i o n l o s s e s . Reddy et a l . (1979) r e p o r t e d that maximum l o s s of ammonia oc c u r r e d at the a i r v e l o c i t y of 0.06 km h" 1 and f o r a i r v e l o c i t y above 0.06 km h " 1 , the r e l a t i v e l o s s of ammonia was assumed to be co n s t a n t . 13 5. S o i l M o i s t u r e There e x i s t s a d i r e c t r e l a t i o n s h i p between s o i l moisture and ammonia v o l a t i l i z a t i o n (Ernst and Massey, 1960; Adriano et a l . , 1971). Adriano et a l . (1971) measured a higher ammonia l o s s from l i q u i d manure a p p l i e d to 90% s a t u r a t e d s o i l than when the same manure was a p p l i e d to 60% s a t u r a t e d s o i l . They i n d i c a t e d that s o i l moisture a f f e c t s ammonia v o l a t i l i z a t i o n because of i t s e f f e c t on the evaporation of moisture and on m i c r o b i a l a c t i v i t y . E r n s t and Massey (1960) r e p o r t e d that the l o s s of ammonia from s o i l to the atmosphere was dependent on the l o s s of moisture from the s o i l . In a 14-day study, they found a s i g n i f i c a n t l y h igher ammonia l o s s from urea that was a p p l i e d to s o i l having 37.5% moisture content than s o i l at 21% moisture. They a t t r i b u t e d the d i f f e r e n c e in ammonia v o l a t i l i z a t i o n r a t e s between the two s o i l s to the f a c t that the s o i l at 21% moisture stopped l o s i n g moisture a f t e r 7 days of a e r a t i o n , while the s o i l at 37.5% moisture was s t i l l i n a d r y i n g process at the end of the 14-day p e r i o d . E r n s t and Massey (1960) a l s o noted the extremely low r a t e of ammonia l o s s from a i r d r i e d s o i l (5% s o i l m o i s t u r e ) , and they a t t r i b u t e d t h i s to incomplete urea h y d r o l y s i s due to a lack of moisture. S i m i l a r r e s u l t s were r e p o r t e d by Donovan and Logan (1983). They a l s o r e p o r t e d a very low ammonia l o s s of 6% from l i q u i d sewage sludge 24 hours a f t e r i t had been 14 a p p l i e d to a i r d r i e d s o i l (6% moisture c o n t e n t ) . They, however, a t t r i b u t e d the lower l o s s e s to the higher moisture t e n s i o n i n the a i r d r i e d s o i l . The lower moisture s o i l absorbed the l i q u i d sludge more r a p i d l y and to g r e a t e r depth than the other s o i l , thus i n c r e a s i n g the depth of s o i l through which ammonia gas would have to d i f f u s e to the s u r f a c e . 6. I n f l u e n c e of Other F a c t o r s Ammonia v o l a t i l i z a t i o n l o s s e s from s u r f a c e - a p p l i e d manure are a l s o a f f e c t e d by the r a t e of i t s a p p l i c a t i o n (Lauer et a l . , 1976; Steenhuis et a l . , 1976). Steenhuis et a l . (1976) r e p o r t e d that d o u b l i n g the a p p l i c a t i o n r a t e i n c r e a s e d the h a l f l i f e f o r ammonia l o s s by about a f a c t o r of 2. Lauer et a l . (1976) measured a g r e a t e r percentage of ammonia l o s s from a l i g h t e r a p p l i c a t i o n (34 t ha" 1) than a h e a v i e r a p p l i c a t i o n (200 t ha" 1 of the same manure. The l i g h t e r manure a p p l i c a t i o n d r i e d more r a p i d l y because of i t s t h i n n e r ground cover, which i n c r e a s e d the r a t e of ammonia l o s s from the manure. I n c r e a s i n g s o i l c a t i o n exchange c a p a c i t y (CEC) r e s u l t e d i n d e c r e a s i n g ammonia l o s s (Stanley and Smith, 1956; Wahhab et a l . , 1958; Fenn and K i s s e l , 1976). Working with anhydrous ammonia, Stanley and Smith (1956) found t h a t ammonia l o s s e s were g r e a t e s t i n sandy s o i l , 15 in t e r m e d i a t e i n s i l t loam, and l e a s t i n c l a y s o i l . Fenn and K i s s e l (1976) a p p l y i n g ammonium sulphate to s o i l s with a wide range of CEC, concluded that ammonia l o s s was i n v e r s e l y r e l a t e d to CEC. 16 IV. MATERIALS AND METHODS A. Experimental S i t e s Losses of ammonia d u r i n g and f o l l o w i n g land a p p l i c a t i o n of l i q u i d manure were measured i n s i x experiments c a r r i e d out on three d i f f e r e n t farms i n B r i t i s h Columbia (Table 1). The d e s c r i p t i o n s of the experimental s i t e s are presented i n Table 2. The le n g t h of grass given i n Table 2 i s the l e n g t h of the blade of gr a s s . The a c t u a l height of the grass canopy on the f i e l d was ranging from 1 to 2 cm. B. Experimental Design and Sampling Procedure 1. Ammonia Loss During A p p l i c a t i o n Three d i f f e r e n t methods of manure a p p l i c a t i o n were used to compare the e f f e c t s of manure spreading methods on the l o s s of ammonia duri n g a p p l i c a t i o n : 1. d a i r y manure with high spray vacuum tanker. 2. d a i r y manure with low spray vacuum tanker. 3. swine manure with high spray vacuum tanker. The same sampling procedure was employed at a l l three experimental s i t e s . The vacuum tanker was backed up to the manure p i t (F i g u r e 1). Samples of the manure were c o l l e c t e d from the manure p i t at the i n l e t of the vacuum tanker, using a 10 cm diameter and 15 cm deep t i n can Table 1. Name, location and manure type of the experimental sites, and the duration of experiments. Farm Name John Viets Location Chilliwak B Casey Gulikers Agassiz Manure Type Swine & Dairy Swine Duration of Experiment June 26 - July 1/85 Feb. 12-18, 1986 Sept. A - 9, 1985 Feb. 13 - 18, 1986 U.B.C. Exp. Farm Oyster River Dairy Aug. 26 - 31, 1985 Mar. 26 - 31, 1986 18 Table 2. Topography, s o i l , and vegetation of experimental sites Farm Topography A level to gently undulating Soil Type Grigg series S i l t y clay loam Vegetation Orchard grass 10 to 20 cm long Very gently sloping (0.5 to 2% grade) F a i r f i e l d -Kent series S i l t loam Orchard grass 10 to 30 cm long level Cassidy-Chemainus series Sandy loam to loam Orchard grass 10 to 20 cm long 19 Figure 1. A vacuum tanker at a manure p i t . 20 which was n a i l e d to the end of a 2 m long wooden s t i c k . Since the manure had not been a g i t a t e d , nine separate samples were taken at approximately 30-second i n t e r v a l s to o b t a i n a r e p r e s e n t a t i v e sample of the manure in the tanker. The samples i n the t i n can were s t i r r e d and subsampled with a small p l a s t i c scoop (approximately 15 mL). The subsamples were then composited i n t o a 150 mL p l a s t i c b o t t l e . At the f i e l d , nine 30 cm diameter and 4 cm deep p l a s t i c c o l l e c t i o n t r a y s (arranged i n 3 by 3 matrix) were p l a c e d on the path of the manure vacuum tanker ( F i g u r e s 2 and 3). Immediately a f t e r spreading, a sample (about 50 grams) of manure was taken from each t r a y f o l l o w i n g a c a r e f u l mixing. Each manure sample was p l a c e d i n a p l a s t i c b o t t l e and p l a c e d i n an i c e box immediately a f t e r c o l l e c t i o n . The t o t a l time taken to f i n i s h a l l sampling from the nine t r a y s was approximately 5 minutes. The samples were then s t o r e d i n a r e f r i g e r a t o r at 4 °C u n t i l the a n a l y s i s . Ambient and manure temperatures, wind speed, and humidity were recorded at the beginning and the end of each experiment. A wet and dry bulb thermometer (Ogawa S e i k i Co. Ltd.) was used to determine ambient temperature and r e l a t i v e humidity. Wind speed was measured with a vane anemometer. 21 Figure 2. C o l l e c t i o n trays on the f i e l d . 22 Figure 3. Lay out of the sampling trays Tractor Manure Vacuum Tanker 10 m o r o 5 m o 5 m o o o 10 m o o o Collection Trays 23 Ammonia l o s s e s were determined by a n a l y s i n g samples and c a l c u l a t i n g the d i f f e r e n c e between the ammonia c o n c e n t r a t i o n (wet weight b a s i s ) of the manure from the p i t and the ammonia c o n c e n t r a t i o n of the samples c o l l e c t e d from the t r a y s . 2. Ammonia Loss F o l l o w i n g A p p l i c a t i o n In order to simulate o p e r a t i o n a l c o n d i t i o n s , and to determine the e f f e c t of the soil/manure system on ammonia l o s s e s , manure was a p p l i e d to a s o i l with a v e g e t a t i v e cover. The s o i l was sampled immediately f o l l o w i n g spreading and at day 1, day 2, and day 5. Nine s o i l cores of 6 cm diameter and 3 cm depth were c o l l e c t e d from the t e s t p l o t (the same 3 by 3 matrix as i n F i g u r e 3) by pushing an i n v e r t e d t i n can i n t o the s o i l . The sharp edge of the can r e a d i l y cut the blades of g r a s s , thus v e g e t a t i o n on the top of the s o i l was c o l l e c t e d with the s o i l c o r e . The s o i l was a l s o sampled at three random l o c a t i o n s p r i o r to spreading to determine the background s o i l n i t r o g e n content f o r each t e s t p l o t . A l l sample co r e s were p l a c e d i n an i c e box a f t e r c o l l e c t i o n to reduce any f u r t h e r changes t h a t might take p l a c e before the sample reached the l a b o r a t o r y . 24 C. A n a l y t i c a l Technique A l l a n a l y s e s were c a r r i e d out i n the Bio-Resource E n g i n e e r i n g Laboratory l o c a t e d at the U n i v e r s i t y of B r i t i s h Columbia. 1. Manure A n a l y s i s Dry matter content of manure was determined by d r y i n g the sample i n a con v e c t i o n oven at 107 °C f o r 24 hours. The pH f o r each manure sample was taken by i n s e r t i n g a pH e l e c t r o d e d i r e c t l y i n t o a moist manure sample (Lauer et a l . , 1976), a l l o w i n g 1 to 2 minutes f o r e q u i l i b r a t i o n before t a k i n g the rea d i n g . The manure samples were d i l u t e d with d i s t i l l e d water and analyzed f o r ammonia content d i r e c t l y on a Technicon Auto Analyzer II (Technicon, 1971). To determine t o t a l K j e l d a h l n i t r o g e n (TKN) of manure, a 1 gram (g) sample of manure was d i g e s t e d with approximately 1.5 g of standard K j e l d a h l d i g e s t i o n reagent (Black, 1965b) and 5 mL of co n c e n t r a t e d s u l p h u r i c a c i d f.or 24 hours on a block d i g e s t e r . The sample was then d i l u t e d to 50 mL and anal y s e d f o r TKN on a Technicon Auto Analyzer II a c c o r d i n g to the method proposed by Technicon I n d u s t r i a l Systems (1971 ). 25 2. S o i l A n a l y s i s In the l a b o r a t o r y , s o i l samples were p l a c e d i n p l a s t i c bags and mixed thoroughly by repeated a c t i o n of shaking and c r u s h i n g the samples by hand. S o i l moisture was determined on an oven-dry weight b a s i s (Black, 1965a) and s o i l pH was measured i n a 1:1 s o i l - w a t e r suspension u s i n g a g l a s s e l e c t r o d e (Black, 1965b). F o l l o w i n g these d e t e r m i n a t i o n s , the r e s t of the sample from the p l a s t i c bag was weighed and p l a c e d i n a blender ( O s t e r i z e r b l e n d e r ) . To e x t r a c t ammonia and n i t r a t e , 1M KC1 was added to give a 1:10 (wt/vol) suspension. The mixture was blended f o r 5 minutes, decanted i n t o a a i r - t i g h t p l a s t i c b o t t l e and kept i n the r e f r i g e r a t o r f o r 24 hours (Lauer et a l . , 1976). The mixture was then c e n t r i f u g e d f o r 10 minutes at 3500 rpm (Western S c i e n t i f i c , H-103N s e r i e s ) and the supernatant was analysed f o r ammonia and n i t r a t e d i r e c t l y on a Technicon Auto Analyzer II (Technicon, 1971). TKN content i n the s o i l sample was a l s o determined by u s i n g a block d i g e s t e r and a Technicon Auto A n a l y z e r II (Technicon, 1971) f o l l o w i n g the same procedure as the manure a n a l y s i s . For s o i l a n a l y s i s , ammonia, TKN, and n i t r a t e c o n c e n t r a t i o n s were c a l c u l a t e d on a dry weight b a s i s . 26 V. RESULTS AND DISCUSSION A. Ammonia Nitrogen Loss During A p p l i c a t i o n Ammonia l o s s d u r i n g a p p l i c a t i o n of manure was c a l c u l a t e d by s u b t r a c t i n g the ammonia c o n c e n t r a t i o n of the waste c o l l e c t e d i n the t r a y from the ammonia c o n c e n t r a t i o n i n the manure p i t (at the i n l e t of the vacuum tanker) and d i v i d i n g by the manure p i t ' s ammonia c o n c e n t r a t i o n to express l o s s e s as percent ammonia l o s s . Losses of ammonia from each t r a y were presented Appendix A. There was no s i g n i f i c a n t d i f f e r e n c e i n ammonia l o s s among the 9 t r a y s p l a c e d i n 3 by 3 matrix ( F i g u r e 3). T h i s i n d i c a t e s that the d i s t r i b u t i o n of ammonia l o s s was not a f f e c t e d by wind. Environmental c o n d i t i o n s ( i e . a i r temperature, r e l a t i v e humidity) and manure c h a r a c t e r i s t i c s are given i n Tables 3 and Table 4. Since there was no r a i n f a l l throughout the e n t i r e experimental p e r i o d , p r e c i p i t a t i o n data i s not shown i n these t a b l e s . 1. E f f e c t of sp r a y i n g method on ammonia l o s s A n a l y s i s of v a r i a t i o n of ammonia l o s s with v a r y i n g h e i g h t of the manure spray was c a r r i e d out by changing the angle of the d e f l e c t o r p l a t e at the rear of the manure 27 Table 3- Environmental conditions and manure characteristics for the experiments in summer. Faro Manure Type Swine Dairy Air Temp. 27.A RH 50 Manure Manure . Std. pH Z TS - Dev. 7.58 6.06+0.21 7.54 10.9 + 0.59 B Swine Dairy 17.8 26.4 70 45 7.82 7.51 3.60 + 0.18 12.5 + 0.52 Table 4. Environmental conditions and manure characteristics for the experiments in winter. Manure Air Temp. RH Manure Manure Manure Std. Farm Type (deg.C) X Temp.( C) pH % TS — Dev. A Swine 5.0 38 6.0 7.56 4.18+0.15 Dairy 6.5 7.70 7.22 + 0.28 B Swine 4.0 40 5.0 7.66 2.58+0.11 C Dairy 8.0 70 10.0 8.43 11.7 + 0.61 28 vacuum tanker. Maximum height of the manure p a r t i c l e from the high spray system reached approximately 5 m from the ground while manure from the low spray system reached only 1.5 to 2 m from the ground. The ammonia l o s s was s i g n i f i c a n t l y g r e a t e r from the high spray system than the low spray system. During the summer, l o s s e s v a r i e d from 9.78 to 11.8% f o r the hig h spray method and from 4.12 to 5.82% f o r the low spray system (Table 5). The d i f f e r e n c e s were s t a t s t i c a l l y s i g n i f i c a n t ( s e c t i o n I i n Appendix B). The higher l o s s e s are a t t r i b u t e d to two f a c t o r s : manure d r o p l e t s i z e and time i n the a i r . I t was observed that the d r o p l e t s i z e of the manure from the hi g h spray system was much s m a l l e r compared to the low spray system. The g r e a t e r r e s i s t a n c e and t u r b u l e n c e p r o v i d e d by the higher angle of the d e f l e c t o r p l a t e appeared to cause the manure stream t o break up i n t o s m a l l e r d r o p l e t s . In the case of the low spray system, the manure was r e l e a s e d from the tanker i n "lumps". As the r e s u l t of smaller d r o p l e t s i z e , i t i s hypothesized that the g r e a t e r a v a i l a b l e s u r f a c e area f o r the ammonia exchange with the a i r caused an a d d i t i o n a l ammonia l o s s i n the hig h spray system. Pote et a l . (1980) a l s o noted that the d r o p l e t s i z e a f f e c t s ammonia l o s s . They s t a t e d that a d r o p l e t diameter of l e s s than 2 mm l o s e s more than 50 percent of i t s ammonia while a d r o p l e t Table 5. Percent ammonia loss during application in summer. Manure * Spray Ammonia (ppm) *103 TKN (ppm) *103 Ammonia Farm Type Method Tank Tray Std. Dev. Tank Tray Std. Dev. Loss (%) A Swine High 1.28 1.15 + 0.04 6.00 5.70 + 0.14 10.1 Dairy High 1.32 1.16 + 0.03 6.32 5.81 + 0.32 11.8 Low 1.38 1.30 + 0.05 6.20 5.81 + 0.39 5.82 B Swine High 2.01 1.82 + 0.11 3.58 3.26 + 0.27 9.02 C Dairy High 1.57 1.41 + 0.07 4.46 4.40+0.46 9.78 Low i 1.57 1.50 + 0.08 4.46 4.20 + 0.33 4.12 * Statstics on the comparison of the higl l and low systems are presented on Appendix C. Table 6. Percent ammonia loss during application in winter. Manure Spray Farm Type Method Ammonia (ppm) *10 Tank Tray Std. Dev. Swine High 2.45 2.32 + 0.23 Dairy High 1.81 1.72 + 0.05 B Swine High 2.97 2.84 + 0.12 Dairy High 2.38 2.20 + 0.08 Low 2.38 2.28 + 0.09 TKN (ppm) *10 Ammonia Tank Tray Std. Dev. Loss (%) 7.48 7.23 + 0.41 5.38 6.33 6.12 + 0.84 5.20 6.06 5.87 + 0.59 4.33 9.17 8.95 + 0.63 7.73 9.17 9.11 + 0.65 4.08 31 of diameter g r e a t e r than 2 mm l o s e s l e s s than 50 percent of i t s ammonia d u r i n g f l i g h t . Furthermore, the f l i g h t time of the manure d r o p l e t s from the high spray system was much longer than that of the low spray system. Since the d r i v i n g f o r c e f o r ammonia v o l a t i l i z a t i o n i s the c o n c e n t r a t i o n g r a d i e n t between the manure d r o p l e t and the a i r , the longer exposure of the d r o p l e t to the a i r r e s u l t e d i n g r e a t e r ammonia l o s s . 2. Temperature There was a s i g n i f i c a n t c o r r e l a t i o n between ambient temperature and the percent ammonia l o s s d u r i n g a p p l i c a t i o n ( F i g u r e 4 ) . The l o s s of ammonia was s i g n i f i c a n t l y g r e a t e r f o r the summer t r i a l as compared to the winter t r i a l . L i n e a r r e g r e s s i o n a n a l y s i s showed that v o l a t i l i z a t i o n i n c r e a s e d with i n c r e a s i n g temperature a c c o r d i n g to the equ a t i o n : % ammonia loss = 4.34 + 0.24T (r = 0.944) where T = ambient temperature ("C) Polynomial r e g r e s s i o n was a l s o used i n the data a n a l y s i s , but the r e s u l t was s i m i l a r to the l i n e a r r e g r e s s i o n . A c c o r d i n g to the above equation, the percent ammonia l o s s d u r i n g a p p l i c a t i o n i n c r e a s e d by 2.4% f o r each 10 °C r i s e i n temperature. For a temperature s h i f t from 0 °C -to 10 °C, the v o l a t i l i z a t i o n l o s s of ammonia was increased by 32 Figure A. Effect of ambient temperature on the percent ammonia loss during manure application. 33 a f a c t o r of 1.55. T h i s r e s u l t i s s i m i l a r to that of Pote et a l . (1980), who r e p o r t e d that f o r each 10 °C r i s e i n ambient temperature, the percent ammonia l o s s i n c r e a s e d by 2% d u r i n g the a p p l i c a t i o n of swine manure with a s p r i n k l e r i r r i g a t i o n system. T h e o r e t i c a l l y , a change i n temperature of an aqueous s o l u t i o n of ammonia i s r e l a t e d to the v o l a t i l i z a t i o n of ammonia from f r e e s u r f a c e . The values of the p a r t i a l p ressure of ammonia over an aqueous s o l u t i o n (5% ammonia s o l u t i o n ) at v a r i o u s temperatures were obtained from the Chemical Engineers' handbook (Perry and C h i l t o n , 1973) and p l o t t e d i n F i g u r e 5. F i g u r e 5 i n d i c a t e s that f o r a temperature s h i f t from 0 °C to 10 °C, the p a r t i a l p r e s s u r e of ammonia over an aqueous s o l u t i o n of ammonia i n c r e a s e s by a f a c t o r of 1.8. A p o s s i b l e e x p l a n a t i o n f o r the higher t h e o r e t i c a l value as compared to the observed value of 1.55 i s that the s o l i d s i n manure may have reduced the i n t e r f a c e f o r gas t r a n s f e r . 34 Figure 5. Partial pressure of ammonia over an aqueous solution (5% ammonia solution) at various temperatures. 35 B. A n a l y t i c a l Method Comparison For S o i l Ammonia A n a l y s i s In order to s i m p l i f y and reduce the time of experiment, the standard method for ammonium e x t r a c t i o n from s o i l (Black 1965b) was m o d i f i e d i n two ways f o r t h i s study: 1. samples of s o i l were blended f o r 5 minutes r a t h e r than shaken f o r 1 hour as recommended by the standard method. 2. 1 M KC1 was used i n p l a c e of the recommended 2 M KC1 to save chemical c o s t and the time of chemical p r e p a r a t i o n . As shown in Appendix C, none of the above changes i n m a t e r i a l s or methods r e s u l t e d i n s i g n i f i c a n t changes i n measured ammonium c o n c e n t r a t i o n s . In a d d i t i o n , a comparison of ammonium e x t r a c t i o n at pH 3 vs pH 6 showed no b e n e f i t i n using an a c i d i f i e d s o l u t i o n to minimize ammonia v o l a t i l i z a t i o n d u r i n g the b l e n d i n g process (Appendix C). Based on these r e s u l t s , a l l s o i l a n a l y s i s r e p o r t e d i n t h i s paper are based on the m o d i f i e d standard method. 36 C. Ammoniacal-N Loss F o l l o w i n g Manure A p p l i c a t i o n Background pH, moisture, ammonia, TKN, and n i t r a t e c o n c e n t r a t i o n s of s o i l before the a p p l i c a t i o n of manure are presented i n Table 7 and 8. Percent ammonia l o s s f o l l o w i n g a p p l i c a t i o n of manure was found by determining the change i n the ammonia c o n c e n t r a t i o n of the s o i l with time and d i v i d i n g by the ammonia c o n c e n t r a t i o n of the s o i l sample taken immediately a f t e r spreading. The most s e r i o u s consequence of ammonia l o s s from manure f o l l o w i n g a p p l i c a t i o n i s the l o s s of n i t r o g e n that c o u l d have been u t i l i z e d as p l a n t n u t r i e n t . L i t t l e N i s l o s t when manure s l u r r y i s immediately i n c o r p o r a t e d i n t o s o i l (Donovan and Logan, 1983). On the other hand, i f there i s a time l a g between manure a p p l i c a t i o n and i n c o r p o r a t i o n , a s i g n i f i c a n t amount of n i t r o g e n may be l o s t . F i g u r e s 6 to 9 show that the ammonia c o n c e n t r a t i o n i n the s o i l samples decreased e x p o n e n t i a l l y with time when manure s l u r r y was spread on the s o i l s u r f a c e having a v e g e t a t i v e cover (orchard g r a s s ) . The c o n c e n t r a t i o n of ammonia drops very s h a r p l y i n the f i r s t two days, f o l l o w e d by a much more gradual change from day 2 to day 5. Up to day 2, the p a t t e r n of the c o n c e n t r a t i o n curve f o r summer resembles that f o r w i n t e r . However, from day 2 to day 5, the slope of the winter curve appears to l e v e l o f f more Table 7. Background pH, moisture, ammonia, TKN, and nitrate concentration of s o i l before manure application i n summer ( s o i l depth « 5 cm). Farm pH + S t (** Moisture - Dev- Content (%) Ammonia Concentration (ppm) TKN *103 Nitrate 5.61 + 0.25 15.4 + 1.0 10.2 + 1.5 2.81 + 0.31 118 + 19 6.11 + 0.36 31.2 + 1.7 45.0 +5.9 3.03 + 0.49 94.0 + 10.8 5.14 + 0.29 20.4 + 1.2 26.4 + 3.2 4.01 + 0.50 68.5 + 8.2 Table 8. Background pH, moisture, ammonia, TKN, and nitrate concentration of s o i l before manure application i n winter ( s o i l depth = 5 cm). Farm „ , Std. Moisture p H - Dev. Content (%) Ammonia Concentration (ppm) TKN *10 3 Nitrate 5.52 + 0.19 25.8 + 1.3 35.1 + 4.1 3.49 + 0.49 71.2 + 10.5 6.42 + 0.31 40.6 + 1.9 60.6 + 7.2 3.77 + 0.42 86.5 + 11.3 C 4.88+0.15 30.1+1.4 39.7+5.1 3.28+0.38 54.4+7.7 CD » 39 in © © summer < 22 t o 27 d e g . c ) —- -+ winter ( 0 to 5 d e g . c ) <ZL CZL cz o ro cz Q J U CZ o CD CD CO CO a CD , (\l \ i \ I 0 T T T 2 3 Time (day) Figure 6. Changes i n ammonia concentration i n s o i l with time following an application of dairy manure at farm A. 40 If) CD O , • L 3- °. S ^ CD* CD CZ CO a ro o CD -© summer ( 2 2 1 0 27 d e g . c ) - 4 - winter < 0 t o 5 d e g . c ) T T 2 3 Time (day) Figure 7. Changes i n ammonia concentration i n s o i l with time following an application of swine manure at farm A. 41 Figure 8. Changes i n ammonia concentration i n s o i l with time following an application of swine manure at farm B. 42 Figure 9. Changes in ammonia concentration in so i l with time following an application of dairy manure at farm C. 43 q u i c k l y than that of the summer curve. Although ammonia-N l o s s e s were only 40 to 45% f o r the a p p l i e d l i q u i d manure a f t e r 5 days i n the winter study ( F i g u r e s 10 and 11), l o s s e s of more than 90% were recorded with l i q u i d d a i r y manure durin g the summer study ( F i g u r e s 12 and 13). Thus, n i t r o g e n l o s s e s can be c o n s i d e r a b l e i f manure/soil c h a r a c t e r i s t i c s and environmental c o n d i t i o n s are f a v o u r a b l e . A m a j o r i t y of the ammonia i n manure s l u r r y can be l o s t i n a very short p e r i o d f o l l o w i n g s u r f a c e a p p l i c a t i o n . Up to 55% of the ammonia i n d a i r y manure can be l o s t w i t h i n 24 hours a f t e r s u r f a c e a p p l i c a t i o n , and a f t e r 2 days, up to 85% of a p p l i e d ammonia-N can be l o s t ( F igure 12). These r e s u l t s support the f i n d i n g s of Hoff et a l . (1981) and Lauer et a l . (1976). Hoff et a l . re p o r t e d ammonia l o s s e s of more than 80% w i t h i n 3 days d u r i n g a greenhouse study u s i n g swine s l u r r y . Lauer et a l . r e p o r t e d that the r a t e of ammonia l o s s from d a i r y manure e x h i b i t e d a h a l f - l i f e as low as 1.86 days, i n d i c a t i n g that 50% of the ammonia content can be l o s t w i t h i n 1 to 2 days. On the other hand, Beauchamp et a l (1982) found that l o s s e s of ammoniacal-N from broadcast a p p l i e d l i q u i d d a i r y manure were only 24 to 33% a f t e r 6 days. A major d i f f e r e n c e between our study and that by Beauchamp et a l . was the c o n d i t i o n of the s o i l s u r f a c e . Beauchamp et a l . 44 CD • CD CD Time (DAY) Figure 10. Percent ammonia loss from swine manure following application at farm A. 45 CD • CD CD Figure 11. Percent ammonia loss from swine manure following application at farm B. 46 CD « CD CD Time (day) Figure 12. Percent ammonia loss from dairy manure following application at farm A. 47 Figure 13. Percent ammonia loss from dairy manure following application at farm C. 48 a p p l i e d the l i q u i d manure to bare s o i l that had been plowed and d i s k e d to smooth the s u r f a c e . Such a bare s o i l s u r f a c e has a high p e r m e a b i l i t y f o r moisture thus l e a d i n g to r a p i d movement of l i q u i d manure i n t o the s o i l . When manure i s a p p l i e d to s o i l with a v e g e t a t i v e cover as i n t h i s study, the s u r f a c e cover decreases the rate at which the manure s o l i d s and l i q u i d s i n t e r a c t with the s o i l . T h i s d i f f f e r e n c e may account f o r pa r t of the d i f f e r e n c e s noted between t h i s study and that of Beauchamp et a l . (1982). 1. Temperature Ammonia l o s s e s from the a p p l i e d manure d u r i n g the winter and summer s t u d i e s are compared i n F i g u r e s 10 to 13. I n c r e a s i n g the temperature of the soil-manure systems i n c r e a s e d the rate of ammonia l o s s . At the end of a 1-day p e r i o d , l o s s e s v a r i e d from 25 to 40 % f o r the winter study and from 30 to 55 % f o r the summer study (Table 9 ) . These l o s s e s resemble those r e p o r t e d by Lauer et a l (1976) who re p o r t e d 25% of ammoniacal-N was l o s t w i t h i n 24 hours of manure a p p l i c a t i o n i n January and 45% ammonia l o s s i n the same 24-hour p e r i o d i n August. S t a t i s t i c a l a n a l y s i s showed that a s i g n i f i c a n t (p=0.95) d i f f e r e n c e e x i s t s between the rate of ammonia l o s s i n summer and i n winter ( s e c t i o n II i n Appendix B). 49 Table 9. Effect of temperature on the loss of ammonia from surface applied manure after 24 hours. Farm Manure Type Swine Dairy Ambient Temperature (deg. C) Winter 5.1 5.1 Summer 27.4 27.4 Ammonia Loss i n 24 hours (Z) Winter 23.4 39.9 Summer 29.8 54.7 B Swine 4.3 17.8 37.3 42.4 Dairy 8.0 26.4 25.9 42.0 50 For a temperature d i f f e r e n c e of 15 to 20 °C from the winter study to the summer study, the l o s s of ammonia in 24 hours was i n c r e a s e d by the f a c t o r of 1.3 to 1.7. T h i s r e s u l t i s s i m i l a r to that of Steenhuis et a l . (1976). They found that the r e a c t i o n r a t e was i n c r e a s e d approximately 1.3 to 3.5 times f o r each 10 °C r i s e i n temperature, when the system temperature was between 0 to 30 °C. Beauchamp et a l (1978, 1982) a l s o r e p o r t e d that the ammonia f l u x f o l l o w e d a d i u r n a l p a t t e r n which was most c l o s e l y r e l a t e d to a i r temperature. The high peak f l u x o c c u r r e d at 20 °C (midday) and minimum l o s s of ammonia occurred i n the e a r l y morning when temperature was r e l a t i v e l y low. Furthermore, temperature not only a f f e c t e d short-term ammonia l o s s e s ,but a l s o had a strong e f f e c t on the long-term ammonia l o s s . At farm B, a higher ammonia l o s s of 94% o c c u r r e d at the end of a 5-day p e r i o d d u r i n g the summer study (26 °C) as compared to a l o s s of 65% d u r i n g the winter study (9 °C) i n the same 5-day p e r i o d ( F i g u r e 11). Adriano et a l (1974) found t h a t , under a greenhouse c o n d i t i o n , temperature a f f e c t e d l o s s e s f o r up to a 4-week p e r i o d . They r e p o r t e d at 10 °C, the average l o s s e s were 39% as compared to 45% at 25 °C d u r i n g the f i r s t 4 weeks. Due to a 30 cm s n o w f a l l o c c u r r i n g 3 days a f t e r manure a p p l i c a t i o n d u r i n g the winter t r i a l at farms A and B, very 51 l i t t l e l o s s of ammonia was found from day 2 to 5. I t i s apparent that the snow cover i n h i b i t e d ammonia v o l a t i l i z a t i o n . 2. Manure Ponding Manure ponding i s a c o n d i t i o n where a l a y e r of f r e e l i q u i d manure i s maintained on the s o i l s u r f a c e and i t i s s t r o n g l y i n f l u e n c e d by the rate of l i q u i d movement i n t o s o i l . Consequently, swine manure which had a g r e a t e r moisture content than d a i r y manure was chosen to ev a l u a t e the e f f e c t of manure ponding on the r a t e of ammonia l o s s . In F i g u r e 14, ammonia l o s s at day 1 was 42.4% f o r farm B where manure ponding was observed as compared to l o s s of 29.8% at farm A where ponding was not n o t i c e d . S t a t i s t i c a l a n a l y s i s showed that ammonia l o s s at day 1 from farm A was s i g n i f i c a n t l y (p=0.95) lower than that from farm B ( s e c t i o n I I I i n Appendix B). Both farms A and B a p p l i e d swine manure to grass f i e l d s with s i m i l a r h e i g h t s and d e n s i t i e s of v e g e t a t i v e cover. The t o t a l s o l i d s c o n c e n t r a t i o n s of the manure from both farms were comparable. However, ambient temperature at farm B was u n u s u a l l y low (ranged from 15 to 18 °C) throughout the experiment as compared to that of farm A (25 to 27 ° C ) . Because of the lower temperature at farm B, the percent of ammonia l o s t from farm B should have been 52 Figure 14. Effect of manure ponding on the loss of ammonia from surface applied swine manure. 53 lower than the l o s s e s from farm A. However, i n the case of farm B, ponding on the s o i l s u r f a c e was observed a f t e r the a p p l i c a t i o n of manure, r e s u l t i n g i n longer exposure of the l i q u i d manure ( c o n t a i n i n g d i s s o l v e d ammonia) to the a i r . In a d d i t i o n , ponding caused a minimal c o n t a c t between the manure l i q u i d and the s o i l . Thus, the c a p a c i t y of the s o i l to adsorb ammonia and i n t e r f e r e with the r a t e of v o l a t i l i z a t i o n was s i g n i f i c a n t l y reduced. As a r e s u l t , the ra t e of ammonia l o s s from farm B was g r e a t e r than that from farm A i n 24 hours. Ponding at farm B disappeared a f t e r 24 hours, and temperature appeared to be a more prominent f a c t o r on the ra t e of ammonia l o s s than s o i l moisture content as the percent ammonia l o s s curve f o r farm A (which was exposed to h igher ambient temperature) i n c r e a s e d much more s h a r p l y than the curve f o r farm A a f t e r 24 hours ( F i g u r e 14). S i m i l a r ponding was observed d u r i n g the winter study at farm B where ammonia v o l a t i l i z e d i n 24 hours was 37.4% of ammonia-N a p p l i e d . T h i s was s i g n i f i c a n t l y higher than ammonia l o s s of 23.4% obtained from farm A without ponding. P o s s i b l e reasons f o r ponding are s o i l compaction and s o i l moisture content. S o i l compaction r e s u l t s i n a r e d u c t i o n of the s o i l ' s i n f i l t r a b i l i t y , which i s a measure of the a b i l i t y of the s o i l p r o f i l e to conduct water (De 54 V r i e s , 1983). S o i l compaction caused by t r a f f i c of machinery and/or l i v e s t o c k may have reduced the i n f i l t r a t i o n of l i q u i d manure i n t o the s o i l , thus c a u s i n g manure ponding. S o i l moisture content s t r o n g l y i n f l u e n c e s the r a t e of l i q u i d movement i n t o s o i l . Donovan and Logan (1983) re p o r t e d that the i n f i l t r a t i o n r a t e of sewage sludge l i q u i d i n t o the s a t u r a t e d s o i l was s i g n i f i c a n t l y lower than the l i q u i d i n f i l t r a t i o n i n t o the a i r - d r i e d s o i l . Consequently, sewage sludge a p p l i e d to the s a t u r a t e d s o i l was exposed to a i r f o r a longer p e r i o d of time. Table 10 i n d i c a t e s t hat ammonia l o s s from the s o i l with higher background s o i l moisture content was alway g r e a t e r than that from the s o i l with lower background s o i l moisture c o n t e n t . Donovan and Logan (1983) a l s o r e p o r t e d a s i g n i f i c a n t l y h igher r a t e of ammonia l o s s from sewage sludge l i q u i d when the s o i l was at s a t u r a t i o n (32% moisture) than from a i r - d r i e d s o i l (6% m o i s t u r e ) . Moisture t e n s i o n s i n the a i r - d r i e d s o i l were hi g h enough a f t e r the a d d i t i o n of the sludge to absorb the sludge l i q u i d . The a i r - d r i e d s o i l absorbed the l i q u i d more r a p i d l y and to a g r e a t e r depth than the s a t u r a t e d s o i l i n c r e a s i n g the depth of the s o i l through which ammonia gas would have to d i f f u s e to the s u r f a c e . 55 Table 10. Effect of s o i l moisture content on percent ammonia loss from swine manure i n 24 hours. Manure S o i l Moisture Standard Ammonia Loss Farm Type Content (%) — Deviation . i n 24 hours ( I ) Summer Winter Summer Winter A Swine 15.4+0.95 25.8+1.26 29.8 23.4 B Swine 31.2 + 1.68 40.6 + 1.89 42.4 37.4 56 Furthermore, Adriano et a l (1974) suggested that s o i l moisture content a l s o i n f l u e n c e s the long-term ammonia l o s s . They r e p o r t e d that ammonia l o s s e s a f t e r 4 weeks of i n c u b a t i o n were higher when l i q u i d manure was spread on s o i l at a near s a t u r a t e d c o n d i t i o n . They found that moisture a f f e c t e d long-term ammonia v o l a t i l i z a t i o n because of i t s e f f e c t on m i c r o b i a l a c t i v i t y . We c o u l d not, however, support t h e i r c o n c l u s i o n with our study because the d u r a t i o n of our experiment was only f o r 5 days. 3. Manure Type Ammonia v o l a t i l i z a t i o n from d a i r y manure and swine manure was compared f o r 5 days f o l l o w i n g manure a p p l i c a t i o n ( F i g u r e 15). Since farm A spreads both d a i r y and swine manure on the same f i e l d d u r i n g the same day, i t was p o s s i b l e to compare ammonia v o l a t i l i z a t i o n l o s s e s from d a i r y and swine manure under s i m i l a r s o i l and environmental c o n d i t i o n s . For swine manure, l o s s e s were 29.8% and 60.6% of a p p l i e d ammonia-N, at day 1 and day 2 r e s p e c t i v e l y . Much higher l o s s e s of 54.7 at day 1 and 84.8% at day 2 were found f o r d a i r y manure (Figure 15). However, under constant exposure to high temperatures f o r 5 days (average 57 Figure 15. Comparison of percent ammonia loss from dairy and swine manure at farm A 58 temperature = 27 ° C ) , l o s s e s from swine manure reached 90.4%, which was approximately the same as the 5-day l o s s of 93.9% from d a i r y manure. A s i m i l a r r e s u l t was obtained f o r the winter study at farm A. Losses of 39.9% and 60.7% at day 1 and day 2, r e s p e c t i v e l y , were re p o r t e d f o r d a i r y manure having a s o l i d s c o n c e n t r a t i o n of 7.22%. Swine manure with a s o l i d s c o n c e n t r a t i o n of 4.18% had l o s s e s of 23.4% at day 1 and 43.3% at day 2 (Table 11). A p o s s i b l e reason f o r the s i z e a b l e d i f f e r e n c e s between swine and d a i r y manure ammonia l o s s e s d u r i n g the f i r s t 2 days i s the manure s o l i d s c o n c e n t r a t i o n . I t was observed t h a t swine manure which had a lower s o l i d s c o n c e n t r a t i o n (6.06% TS) moved much more r e a d i l y through the v e g e t a t i v e cover and i n t o the s o i l as compared to d a i r y manure with i t s higher s o l i d s c o n c e n t r a t i o n (10.9% TS). D a i r y manure appeared to be p h y s i c a l l y i n t e r c e p t e d by the v e g e t a t i v e cover and tended to s i t on the blades of grass and on top of the s o i l , thus i n c r e a s i n g the p o t e n t i a l f o r ammonia v o l a t i l i z a t i o n . 4. A p p l i c a t i o n Rate of Manure Manure a p p l i c a t i o n r a t e s throughout the experiment were f a i r l y c o n s i s t e n t , except at farm C d u r i n g the summer study where an u n u s u a l l y high a p p l i c a t i o n r a t e was observed (Table 12). The a p p l i c a t i o n r a t e of manure was 59 Table 11. Effect of manure solids concentration on the loss of ammonia from surface applied manure. Period of Exp. Manure T y P e % Total Std. Solids — Dev. Ammonia Loss (%) day 1 day 2 Summer Swine Dairy 6..06 + 0.21 29.8 60.6 10.9 + 0.59 54.7 84.8 Winter Swine Dairy 4.18 + 0.15 23.4 43.3 7.22 + 0.28 39.9 60.7 Table 12. Manure application rate. Farm Manure T y P e Application Rate, tonne/ha Summer Winter Swine Dairy 38 52 22 40 B Swine 42 31 Dairy 138 44 60 c a l c u l a t e d by measuring the q u a n t i t y of manure i n the s o i l core sample which had a f i x e d s u r f a c e a r ea. F i g u r e 16 compares the ammonia v o l a t i l i z a t i o n p a t t e r n over 5 days between d a i r y manure from farm A and farm C. It c l e a r l y i n d i c a t e s that the amount of ammonia that v o l a t i l i z e d from a gi v e n manure on the s o i l over a p e r i o d of time i s a f f e c t e d by the r a t e of i t s a p p l i c a t i o n . At farm C, l o s s e s were 41.8% at day 1 and 63.3% at day 2 with a manure a p p l i c a t i o n r a t e of 138 t h a " 1 . Higher l o s s e s of 54.7% and 84.8% were r e p o r t e d at farm A on day 1 and day 2, r e s p e c t i v e l y , with an a p p l i c a t i o n r a t e of 52 t h a " 1 . D a i r y manure from both farms had approximately the same t o t a l s o l i d s c o n c e n t r a t i o n (TS =10.9%; TS =12.5%) and spreading was c a r r i e d out under s i m i l a r environmental c o n d i t i o n s . I t was observed that with the higher a p p l i c a t i o n r a t e , a t h i c k e r and more uniform l a y e r of manure formed on top of the s o i l , thus lowering the percentage of f r e s h manure th a t was a c t u a l l y exposed to the a i r . In a d d i t i o n , as the s u r f a c e of the manure l a y e r d r i e d , i t caked and formed a s o l i d b a r r i e r which may have prevented d i f f u s i o n of ammonia gas to the a i r . A s i m i l a r r e s u l t was found by Lauer et a l . (1976). They a l s o suggested a g r e a t e r percentage of manure ammonia-N was l o s t through v o l a t i l i z a t i o n from a shallower 61 Figure 16. Effect of manure application rate on the rate of ammonia loss from surface applied manure. 62 a p p l i c a t i o n than from a heavier a p p l i c a t i o n of the same manure. They r e p o r t e d that the q u a n t i t i e s of N l o s t by ammonia v o l a t i l i z a t i o n before plowing the manure under were 61 and 85 %, r e s p e c t i v e l y , at the 200 and 34 t ha" 1 r a t e s of manure a p p l i c a t i o n . T h i s was a t t r i b u t e d to the much t h i n n e r c o v e r i n g of manure on the s o i l s u r f a c e at the lower r a t e of manure, which promoted more r a p i d d r y i n g , thus i n c r e a s i n g the p o t e n t i a l f o r ammonia v o l a t i l i z a t i o n . 5. E f f e c t of pH The pH of the soil-manure system remained w i t h i n 1 pH u n i t throughout the experiment (Table 13 and 14); consequently, an e x t e n s i v e i n v e s t i g a t i o n on the e f f e c t of pH on the ammonia v o l a t i l i z a t i o n was not p o s s i b l e i n our study. T h e o r e t i c a l l y , an aqueous form of ammonia i n s o l u t i o n e x i s t s i n e q u i l i b r i u m with ammonium i o n s , as shown: ^ ( a q . ) + H 2 ° — N H4 + 0 H ' As the pH of the system i s i n c r e a s e d above 7, the e q u i l i b r i u m i s s h i f t e d to the l e f t ; and the ammonium ion i s converted to ammonia, which i s h i g h l y s u s c e p t i b l e t o v o l a t i l i z a t i o n (Reddy et a l . , 1979). Because the above r e a c t i o n i s pH dependent, the percentage d i s t r i b u t i o n of 63 Table 13 Soil pH during summer over 5 day sampling period. Manure pH Farm Type day 0 day 1 day 2 day 5 A Swine 6.56 6.49 6.27 6.07 Dairy 7.19 7.13 7.16 7.00 B Swine 6.96 6.82 6.92 6.85 C Dairy 6.64 6.81 6.37 6.17 Table 14 Soil pH during winter over 5 day sampling period. Manure pH Farm Type day 0 day 1 day 2 day 5 A Swine 6.53 6.28 6.23 5.84 Dairy 6.69 6.51 6.41 6.05 B Swine 6.82 6.88 — 6.74 C Dairy 6.70 6.81 6.58 6.66 64 ammonia and ammonium ion can be computed using the f o l l o w i n g equation (Metcalf and Eddy, 1979): NH 100 % ammonia = * 100 = NH3 + NH+ 1 +• ( KjH 4"]/ K W ) where: K = ionization constant for water w = ionization constant for ammonia [H +]= hydrogen ion concentration The above equation was p l o t t e d i n F i g u r e 17 us i n g the i o n i z a t i o n c o n s t a n t s of water and ammonia at 25 °C. F i g u r e 17 i n d i c a t e s that f o r the pH range of 5 to 7 (as i n t h i s s t u d y ) , the vast m a j o r i t y of the t o t a l ammoniacal-N e x i s t s as ammonium i o n s . T h e r e f o r e , an i n c r e a s e i n the r a t e of ammonia l o s s due to a pH s h i f t from 5 to 7 would be minimal; i n other words, at low and n e u t r a l pH, changing pH may not a f f e c t the r a t e of ammonia l o s s . 6. N i t r o g e n Balance Ammonia, TKN and n i t r a t e c o n c e n t r a t i o n s of the s o i l samples (dry weight b a s i s ) from 0 to 5 days a f t e r manure a p p l i c a t i o n are presented i n Table 15 and 16. An attempt was made to assess whether these measurements were u s e f u l 65 Figure 17. Percentage of ammonia in solution at equilibrium at various pH's. Table 15. Changes in ammonia, TKN, and nitrate concentration in s o i l over 5 days following an application of liquid manure in summer. Farm B C B C B C Manure Type Swine Dairy Swine Dairy Swine Dairy Swine Dairy Swine Dairy Swine Dairy day 0 213 + 39 313 + 51 472 + 32 1200 + 119 3.53 + 0.16 3.88 + 0.35 6.17 + 0.23 5.79 + 0.13 11.7 + 1.8 11.8 + 1.4 14.8 + 2.6 8.40 + 0.85 day 1 day 2 Ammonia Concentration (ppm) 150 + 29 142 + 25 272 + 20 700 + 124 84.1 + 15.0 47.5 + 14.9 169 + 37 441 + 55 TKN Concentration (ppm) *10 3.47+0.41 3.40+0.28 3.69+0.50 3.58+0.51 5.97 + 0.44 5.85 + 0.34 5.39 + 0.29 5.13 + 0.29 Nitrate Concentration (ppm) 23.7 + 3.2 33.2 + 4.3 17.0 + 1.6 23.0 + 1.8 16.2 +1.8 28.0 + 4.5 13.9 + 1.2 30.2 + 4.1 day 5 20.5 + 3.5 19.2 + 4.1 125 + 21 74.0 + 20.0 3.30 + 0.14 3.50 + 0.32 5.76 + 0.26 4.74 + 0.15 61.4 + 6.6 60.3 + 7.2 48.5 + 5.1 71.0 + 12.5 Table 16. Changes in ammonia, TKN, and nitrate concentration in s o i l over 5 days following an application of liquid manure in winter. Farm B C B C B C Manure Type Swine Dairy Swine Dairy Swine Dairy Swine Dairy Swine Dairy Swine Dairy day 0 282 + 10 381 + 61 738 + 137 564 + 98 2.94 + 0.21 3.46 + 0.35 4.39 + 0.65 4.79 + 0.28 14.6 + 2.2 15.6 + 2.3 26.1 + 4.3 10.6 + 1.9 day 1 day 2 Ammonia Concentration (ppm) 216 + 37 229 + 29 463 + 62 418 + 77 160 + 28 146 + 13 272 + 26 TKN Concentration (ppm) *10' 2.84 + 0.18 3.18 + 0.31 4.24 + 0.50 4.62 + 0.41. 2.68 + 0.14 3.11 + 0.29 4.51 + 0.29 Nitrate Concentration (ppm) 27.2 + 3.9 23.6 + 2.5 49.0 + 8.7 23.1 + 4.3 ; 40.9 + 4.3 41.8 + 4.3 35.5 + 8.5 day 5 141 + 25 148 + 10 434 + 84 196 + 34 2.63 + 0.15 3.20 + 0.22 3.83 + 0.51 4.39 + 0.50 32.4 + 4.3 35.2+6.1 19.0 + 1.5 64.5 +9.8 68 i n e s t i m a t i n g v o l a t i l i z a t i o n l o s s e s f o l l o w i n g manure a p p l i c a t i o n . The amount of n i t r a t e formation was s u b t r a c t e d from the t o t a l r e d u c t i o n i n TKN to o b t a i n the amount of ammonia l o s t due to v o l a t i l i z a t i o n . Crane et a l . (1981) r e p o r t e d that i n an e n v i r o n m e n t a l l y c o n t r o l l e d chamber with minimal l e a c h i n g allowed, a l l TKN r e d u c t i o n i n a soil-manure system was due to the sum of v o l a t i l i z a t i o n of ammonia and the n i t r a t e f o r m a t i o n . In Table 17 and 18, measured val u e s of ammonia l o s s i n 5 days were compared to the c a l c u l a t e d v a l u e s . In the summer study, the c a l c u l a t e d estimates of ammonia v o l a t i l i z a t i o n were very c l o s e ( w i t h i n about 10%) to the measured data (Table 17), i n d i c a t i n g that these c a l c u l a t e d v a l u e s may be u s e f u l i n p r o v i d i n g a check f o r the .ammonia v o l a t i l i z e d . However, as expected, the r e s u l t s from the winter study (Table 18) that was c a r r i e d out under the 30 cm snow cover were very i n c o n s i s t e n t . Some l a r g e d i f f e r e n c e s between the measured and c a l c u l a t e d v a l u e s were observed (Table 18). Leaching of n i t r a t e due to the snow m e l t i n g may have accounted f o r some of the l a r g e d i f f e r e n c e s observed between the measured and c a l c u l a t e d v a l u e s . Table 17. Comparison of calculated and measured value of ammonia loss in 5 days in summer. Farm Manure T y P e Swine Dairy TKN l o s s i n 5 days (ppm) 230 380 N i t r a t e gain i n 5 days (ppm) 49.7 48.5 Ammonia l o s s i n 5 days (ppm) C a l c u l a t e d 180 Measured 192 332 294 Swine 410 81.2 329 347 Dairy 1050 62 .6 997 1129 * Caculated ammonia loss = TKN loss - nitrate gain Table 18. Comparison of calculated and measured value of ammonia loss i n 5 days in winter. Farm Manure Type TKN l o s s i n 5 days (ppm) N i t r a t e gain i n 5 days (ppm) Ammonia l o s s i n 5 days (ppm) * C a l c u l a t e d Measured Swine Dairy 310 260 17 . 8 19 .6 292 240 141 233 Swine 560 -7.1 567 304 o Dairy 400 73.9 326 368 * calculated ammonia loss = TKN loss - nitrate gain 71 VI. SUMMARY Increased awareness of the p o t e n t i a l of manure n i t r o g e n , both as a f e r t i l i z e r and as a environmental p o l l u t a n t , has i n t e n s i f i e d i n t e r e s t i n the e f f i c i e n t u t i l i z a t i o n of the n u t r i e n t s i n farm manure. In t h i s study, v o l a t i l i z a t i o n of ammonia d u r i n g and f o l l o w i n g land a p p l i c a t i o n of l i q u i d manure was measured under f i e l d c o n d i t i o n s . If n i t r o g e n c o n s e r v a t i o n i s the primary goal of a farmer, manure should be a p p l i e d with a low spray system to minimize the l o s s e s d u r i n g a p p l i c a t i o n and fo l l o w e d with immediate i n c o r p o r a t i o n of manure i n t o the s o i l to minimize the l o s s e s f o l l o w i n g a p p l i c a t i o n . Although a hig h spray system tended t o spread manure much more u n i f o r m l y than a low spray system, the l o s s of ammonia from manure a p p l i e d with the high spray system was about 5% higher than t h a t from the low spray system. However, i f the manure i s not plowed i n t o the s o i l w i t h i n a s h o r t p e r i o d of time t h i s d i f f e r e n c e i s n e g l i g i b l e as up to 50% of the ammonia-N i n the s u r f a c e a p p l i e d manure may be l o s t w i t h i n 24 hours of a p p l i c a t i o n . I f there i s to be any delay i n i n c o r p o r a t i n g manure f o l l o w i n g a p p l i c a t i o n , i t may be a good management p r a c t i c e to a v o i d spreading on hot days and days f o l l o w i n g a r a i n f a l l ( I t would have i n c r e a s e d the s o i l moisture content) because the r a t e of 72 ammonia l o s s from manure i s d i r e c t l y p r o p o r t i o n a l to the i n c r e a s e i n ambient temperature and s o i l moisture content. In a d d i t i o n , a higher r a t e of manure a p p l i c a t i o n appears to r e s u l t i n reduced percentage l o s s of the N a p p l i e d . T h i s must be balanced a g a i n s t a p o t e n t i a l o v e r - a p p l i c a t i o n of manure which may b u i l d up the n u t r i e n t content of the s o i l beyond the crop requirements and have a d e t r i m e n t a l e f f e c t on the crop. 73 V I I . CONCLUSIONS A. Ammoniacal-N l o s s d u r i n g a p p l i c a t i o n The percentage of ammonia l o s t d u r i n g the a p p l i c a t i o n of manure with a high spray system v a r i e d from 9.0 to 12.0 % i n the summer. The percentage of ammonia l o s t d u r i n g the a p p l i c a t i o n of manure with a low spray system v a r i e d from 4.0 to 7.0 % in the summer. The d i f f e r e n c e i n l o s s e s i s a t t r i b u t e d to d r o p l e t s i z e and f l i g h t time. The percentage of ammonia l o s t d u r i n g a p p l i c a t i o n of manure d u r i n g summer was always g r e a t e r than the percentage l o s t d u r i n g winter. Over the temperature range of 4 to 25 °C, each i n c r e a s e of 10 °C r e s u l t e d i n an i n c r e a s e i n ammonia l o s s of 2.4%. B. Ammoniacal-N l o s s f o l l o w i n g a p p l i c a t i o n The percentage of ammonia l o s s d u r i n g the f i r s t 24 hours a f t e r a p p l i c a t i o n was a f u n c t i o n of temperature, manure type, s o i l moisture content, and manure a p p l i c a t i o n r a t e . the percentage of ammonia l o s t a f t e r a p p l i c a t i o n d u r i n g summer was always g r e a t e r than the percentage l o s t d u r i n g winter. Losses i n 24 hours v a r i e d from 25 74 to 40 % f o r the winter study (4 to 9 °C) and from 30 to 55 % f o r the summer study (18 to 27 ° C ) . the percentage of ammonia l o s t i n 24 hours from d a i r y manure was higher than that from swine manure by a f a c t o r of about 2. The d i f f e r e n c e i n l o s s e s i s a t t r i b u t e d to manure s o l i d s c o n c e n t r a t i o n . an i n c r e a s e i n s o i l moisture content by a f a c t o r of two i n c r e a s e d the percentage of ammonia l o s s i n 24 hours by approximately the same f a c t o r . a much t h i n n e r manure cover at 52 t ha" 1 r e s u l t e d i n a gr e a t e r percentage of ammonia l o s s (54.7%) i n 24 hours than that of 138 t ha" 1 (42.0%). The percentage of ammonia l o s t 48 hours a f t e r a p p l i c a t i o n v a r i e d from 43.3 to 84.8%. The d i f f e r e n c e s i n l o s s are a t t r i b u t e d to temperature, manure type, and manure a p p l i c a t i o n r a t e . The percentage of ammonia l o s t 5 days a f t e r a p p l i c a t i o n v a r i e d from 50.0 to 93.9%. Temperature and a 30 cm snow cover d u r i n g the winter study were the primary f a c t o r s f o r the d i f f e r e n c e s i n ammonia l o s s a f t e r 5 days. 75 V I I I . RECOMMENDATIONS A number of gen e r a l recommendations r e g a r d i n g n i t r o g e n c o n s e r v a t i o n d u r i n g and f o l l o w i n g a p p l i c a t i o n of manure can be put f o r t h based on the r e s u l t s of t h i s study. 1. Manure should be a p p l i e d with a low spray system and fol l o w e d with immediate i n c o r p o r a t i o n of manure i n t o the s o i l . 2. I f the manure i s not plowed i n t o the s o i l w i t h i n a short p e r i o d of time, the f o l l o w i n g management p r a c t i c e s are recommended: a. Since ammonia v o l a t i l i z a t i o n i s s t r o n g l y a f f e c t e d by ambient temperature, manure spreading should be ' avoided on hot days. b. To prevent manure ponding, manure should not be a p p l i e d on s o i l with low i n f i l t r a b i l i t y ( i e . s a t u r a t e d or compacted s o i l s ) . c. Manure with high s o l i d s c o n c e n t r a t i o n should be d i l u t e d before a p p l i c a t i o n to i n c r e a s e the r a t e of movement through a v e g e t a t i v e cover and i n t o s o i l . d. A higher r a t e of manure a p p l i c a t i o n i s b e n e f i c i a l (as d i s c u s s e d on page 58). However, manure should not be o v e r - a p p l i e d to a p o i n t where the n u t r i e n t c o ntents b u i l d i n g up i n the s o i l exceeds the crop requirements. 76 LITERATURE CITED A d r i a n o , D. C , A. C. Chang, and R. S h a r p l e s s . 1974. N i t r o g e n l o s s from manure as i n f l u e n c e d by m o i s t u r e and t e m p e r a t u r e . J . E n v i r o n . Q u a l . , V o l . 3, no. 3, pp 258-161. B r i t i s h Columbia M i n i s t r y of A g r i c u l t u r e and Food. Farm and Food S t a t i s t i c s , A p r i l , 1984. Beauchamp, E. G., G. E. K i d d , and G. T h u r t e l l . 1978. Ammonia from sewage s l u d g e a p p l i e d i n the f i e l d . J . E n v i r o n . Q u a l . , V o l . 7, no. 1, pp 141-146. Beauchamp, E. G., G. E. K i d d , and G. T h u r t e l l . 1982. Ammonia v o l a t i l i z a t i o n from l i q u i d d a i r y c a t t l e manure i n t h e f i e l d . Can. J . S o i l S c i . 62:11-19. B l a c k , C. A. 1965a. Methods of s o i l a n a l y s i s - P a r t 1. P h y s i c a l and m i n e r a l o g i c a l p r o p e r t i e s , i n c l u d i n g s t a t i s t i c s of measurement and s a m p l i n g . American S o c i e t y of Agronomy, I n c . M a d i s o n , W i s c o n s i n . P 92. B l a c k , C. A. 1965b. Methods of s o i l a n a l y s i s - P a r t 2. Chemical and m i c r o b i a l p r o p e r t i e s . American S o c i e t y of Agronomy, I n c . M a d i s o n , W i s c o n s i n . P 801 B u l l e y , N. R. And N. Holbek. 1982. N i t r o g e n mass b a l a n c e s f o r d a i r y farms from f e e d t o f i e l d . Can. A g r i c . Eng. 24:19-23. Crane, S. R., P. W. Westerman, and M. R. Overc a s h . 1981. S h o r t - t e r m c h e m i c a l t r a n s f o r m a t i o n s f o l l o w i n g l a n d a p p l i c a t i o n of p o u l t r y manure. T r a n s a c t i o n s of the ASAE 24:382-390. Denmead, 0. T., J . S. Simpson, and J . T. F r e n e y . 1974. Ammonia f l u x i n t o t h e atmosphere from a g r a z e d p a s t u r e . S c i e n c e 185:609-610. De V r i e s , J . 1983. D e g r a d a t i o n e f f e c t s of s o i l c o m p a c t i o n . P r o c e e d i n g s of the 8 t h B.C. S o i l S c i e n c e Workshop. P 91-121. Donovan, W. C. And T. J . Logan. 1983. F a c t o r s a f f e c t i n g ammonia v o l a t i l i z a t i o n from sewage s l u d g e a p p l i e d t o s o i l i n a l a b o r a t o r y s t u d y . J . E n v i r o n . Q u a l . , V o l . 12, no.4, pp 584-590. E l l i o t , L. F., G. E. Schuman, and F. G. V i e t s , J r . 1971. V o l a t i l i z a t i o n of n i t r o g e n c o n t a i n i n g compounds from beef c a t t l e a r e a s . S o i l S c i . Soc. Am. P r o c . 35:752-755. 77 E r n s t , J . W. And H. F. Massey. i 9 6 0 . The e f f e c t s of s e v e r a l f a c t o r s on v o l a t i l i z a t i o n of ammonia formed from urea i n the s o i l . S o i l S c i . Soc. Am. P r o c . 24:87-90. Fenn, L. B. And D. E. K i s s e l . 1976. The i n f l u e n c e of c a t i o n exchange c a p a c i t y and d e p t h of i n c o r p o r a t i o n on ammonia v o l a t i l i z a t i o n from ammonium compounds a p p l i e d t o c a l c a r e o u s s o i l s . S o i l S c i . Soc. Am. J . 40:394-398. Har p e r , L. A., V. R. C a t c h p o o l e , R. D a v i s , and K. L. W e i r . 1983. Ammonia v o l a t i l i z a t i o n : s o i l , p l a n t , and m i c r o c l i m a t e e f f e c t s on d i u r n a l and s e a s o n a l f l u c t u a t i o n s . Agron. J . 75:212-218. H o f f , J . D., D. W. N e l s o n , and A. L. S u t t o n . 1981. Ammonia v o l a t i l i z a t i o n from l i q u i d swine manure a p p l i e d t o c r o p l a n d . J . E n v i r o n . Q u a l . , V o l . 10, no.1, pp 90-95. H u t c h i n s o n , G. L. And F. G. V i e t s , J r . 1969. N i t r o g e n enrichment of s u r f a c e water by a b s o r p t i o n of ammonia v o l a t i l i z e d from c a t t l e f e e d l o t s . S c i e n c e 166:514-515. K o e l l i k e r , J . K. And J . R. M i n e r . 1973. D e s o r p t i o n of ammonia from a n a e r o b i c l a g o o n s . T r a n s a c t i o n s of the ASAE 16:148-150. L a u e r , D. A., D. R. B o u l d i n , and S. D. K l a u s n e r . 1976. Ammonia V o l a t i l i z a t i o n from D a i r y Manure Spread on t h e S o i l S u r f a c e . J . E n v i r o n . Q u a l . , V o l . 5, no. 2, pp 134-141. Luebs, R. E., K. R. D a v i s , and A. E. Laag. 1973. Enrichment of t h e atmosphere w i t h n i t r o g e n compounds v o l a t i l i z e d from a l a r g e d a i r y a r e a . J . E n v i r o n . Q u a l . , V o l . 2, no. 2, 137-141. M e t c a l f , L. And H. P. Eddy. 1979. Wastewater E n g i n e e r i n g : t r e a t m e n t , d i s p o s a l , r e u s e . 2nd ed. M c G r a w - H i l l Book Co. P735. M i l l s , H. A., A. V. B a r k e r , and D.N. Maynard. 1974. Ammonia v o l a t i l i z a t i o n from s o i l s . Agron. J . 66:355-358. P e r r y R. H. And C. H. C h i l t o n . 1973. C h e m i c a l E n g i n e e r s ' Handbook. M c G r a w - H i l l Book Co. 3-67. P e t e r s , R. E. And D. L. R e d d e l l . 1973. Ammonia v o l a t i l i z a t i o n and n i t r o g e n t r a n s f o r m a t i o n s i n h i g h pH s o i l s used f o r beef manure d i s p o s a l . ASAE Paper no. 73-428. 78 Pote, J . W., J . R. Miner, and J . K. K o e l l i k e r . 1980. Ammonia l o s s e s d u r i n g s p r i n k l e r a p p l i c a t i o n of animal wastes. T r a n s a c t i o n s of the ASAE- 23 :1 202-1 21 2. Reddy, K. R., R. K h a l e e l , M. R. Overcash, and P. W. Westerman. 1979. A nonpoint source model f o r land areas r e c e i v i n g animal wastes: I I . Ammonia v o l a t i l i z a t i o n . T r a n s a c t i o n s of the ASAE 22:1398-1405 St a n l e y , F. A. And G. E. Smith. E f f e c t of s o i l moisture and depth of a p p l i c a t i o n on r e t e n t i o n of anhydrous ammonia. S o i l S c i . Soc. Am. Proc. 20:557-561. Steenhuis, T. S. And J . C. Converse. 1976. Ammonia v o l a t i l i z a t i o n of winter spread manure. ASAE Paper no. 76-4514. Sutton, A. L. 1981 Maximizing the v a l u e of swine manure, P i g American, A Watt P u b l i c a t i o n , May, 1981, pp 14-16 Vl e k , P. L. And J . M. Stumpe. 1978. E f f e c t s of s o l u t i o n chemistry and environmental c o n d i t i o n s on ammonia v o l a t i l i z a t i o n l o s s e s from aqueous systems. S o i l S c i . Soc. Am. J . 42:416-421. Technicon Auto Analyzer II manual. 1971. I n d u s t r i a l Method No. 98-70W, Ammonia i n Water and Wastewater; Method No. 103-70A, TKN i n Water and Wastewater; Method No. 100-70W, N i t r i t e and N i t r a t e i n Water and Wastewater. Technicon I n d u s t r i a l System, Tarrytown, N.Y. Wagner, G. H. And G. E. Smith. 1958. N i t r o g e n l o s s e s from s o i l s f e r t i l i z e d with d i f f e r e n t n i t r o g e n c a r r i e r s . S o i l S c i . 85:125-129. Wahhab, A., M. S. Randhawa, and S. Q. Alam. 1956. Loss of ammonia from ammonium s u l f a t e under d i f f e r e n t c o n d i t i o n s when a p p l i e d to s o i l s . S o i l S c i . 84:249-255. Watkins, S. H., R. F. Strand, D. S. D e b e l l and J . Esch, J r . 1972. F a c t o r s i n f l u e n c i n g ammonia l o s s e s from urea a p p l i e d to northwestern f o r e s t s o i l s . S o i l S c i . Soc. Am. Proc. 36:354-357. 79 APPENDIX A The ammonia concentration of manure from nine trays which were placed on the f i e l d in 3 by 3 matrix. 0C"ay tray number © © © © © © © © © Dairy manure applied with the high spray system ammonia concentration of manure (ppm) Tray no. Farm A Farm C Summer Winter Summer Winter 1 1120 1660 1440 2150 2 1130 1730 1330 2190 3 1160 1770 1420 2230 4 1220 1770 1430 2210 5 1170 1730 1470 2270 6 1160 1630 1400 2090 7 1150 1730 1400 2100 8 1190 1700 1430 2330 9 1190 — — Average 1160 1720 1410 2200 Std. Dev. 30 50 70 80 80 II. Dairy manure applied with low spray system. ammonia concentration of manure (ppm) Tray no. Farm A Farm C Summer Winter Summer Winter 1 1130 — 1540 2230 2 1290 — 1450 2270 3 1350 — 1490 2250 4 1270 — 1460 2150 5 1350 — 1540 2430 6 1320 -- 1550 2310 7 1260 — 1540 2250 8 1286 -- 1460 2370 9 1220 — 1500 — Average 1300 — 1500 2280 Std. Dev. 50 70 90 III. Swine manure applied with the high spray system ammonia concentration of manure (ppm) Tray no. Farm A Farm B Summer Winter Summer Winter 1 1170 2050 1870 2870 2 1170 2340 1750 2850 3 1130 2100 1750 2910 4 1180 2300 1920 2950 5 1170 1980 1920 2930 6 1050 2450 1810 2800 7 1150 2560 1870 2840 8 1170 2530 1870 2580 9 1130 2550 1840 — Average Std. Dev. 1150 2320 40 230 1820 110 2840 120 81 APPENDIX B Stat i s t i c a l Analysis I. To test whether the loss of ammonia from a high spray vacuum tanker during applicationis significantly higher than that from a low spray vacuum tanker. a. Ammonia loss during application (ppm) - Farm A (summer) Tray Ammonia Loss during Application (ppm) High Spray System Low Spray System ) 1 200 60 2 190 80 3 160 20 4 100 100 5 150 20 6 170 30 7 170 110 8 130 90 9 130 160 Mean 160 75 Standard Deviation (S) 30 50 82 Null Hypothesis ( H Q ) : Mean^ = Mean. Alternative Hypothesis (Ha) : Meai Mean. L ( ijjj - 1 ) s j + ( - 1 )s£ "H + n L " 2 = 41 T = = 4.40 L At = 0.05, theoretical T = 2.12 Since calculated T value i s greater than the theoretical T value, the null hypothisis (HQ) i s rejected. Therefore, the loss of ammonia from the high spray system i s significantly higher than that from the low spray system. 83 b. Ammonia loss during application (ppm) - Farm C (summer) Tray Ammonia Loss during Application (ppm) High Spray System Low Spray System 1 120 30 2 240 120 3 150 80 4 140 110 5 190 30 6 170 20 7 170 30 8 150 110 9 150 60 Mean 170 70 Standard Deviation 40 40 S = 40 P T = 5.30 At =0.05, theoretical T = 2.12 is less than the calculated T of 5.30. Therefore, the loss of ammonia from the high spray system i s Significantly higher than that from the low spray system. 84 Statistical Analysis (continued) II. To test whether the rate of ammonia loss following application is significantly higher i n summer than in winter. Farm % ammonia loss in 24 hours Summer Winter A 29.8 23.4 54.7 39.9 B 42.4 25.9 C 41.8 37.3 A randomized block design i s used to decrease the uncontrolled variation caused by four different experimental sites. The data i s transformed using a log transformation to meet the requirement of normal distribution. 85 Treatments Block Summer Winter Total a 1.47 1.36 2.83 b 1.74 1.60 3.34 c 1.63 1.41 3.04 d 1.62 1.57 3.19 Total 6.46 5.94 12.40 ANOVA Source df SS MS F C r i t i c a l F Block 3 0 .0711 0 .0237 8.46 9. 28 Treatment 1 0 .0338 0 .0338 12.07 10. 13 Error 3 0 .0080 0 .0028 Total 7 0 .1129 Since the computed value of F exceeds the c r i t i c a l value, there i s sufficient evidence to conclude that a significant difference exists between the rate of ammonia loss in summer and in winter. 86 Stat i s t i c a l Analysis (continued) III. To test.whether ammonia loss at day 1 from farm B is significantly higher than that from farm A. % ammonia loss after 24 hours  Samples Farm A Farm B 1 31.8 44.4 2 30.2 42.1 3 44.1 38.5 4 16.9 27.8 5 28.2 52.9 6 14.4 42.3 7 22.2 51.1 8 35.5 37.9 9 39.6 37.0 A randomized block design i s used to decrease the uncontrolled variation caused by two different experimental sites. The data i s transfromed using a log transformation to meet the requirement of normal distribution. 87 Block Treatment a. _b Total 1 1.50 1.65 3.15 2 1.48 1.62 3.10 3 1.64 1.59 3.23 4 1.23 1.44 2.67 5 1.45 1.72 3.17 6 1.16 1.63 2.79 7 1.35 1.71 3.06 8 1.55 1.58 3.13 9 1.60 1.59 3.17 Total 12.96 14.49 27.45 Anova Source df SS MS F C r i t i c a l F Block 1 0.130 0.130 8.125 5.32 Treatment 8 0.210 0.026 1.625 3.44 Error 8 0.130 0.016 Total 17 0.470 Since the computed value of F exceeds the c r i t i c a l value, there i s sufficient evidence to conclude that a significant difference exists between the rate of ammonia loss in summer and in winter. 88 APPENDIX C Comparison of S o i l Ammonium E x t r a c t i o n Method  O b j e c t i v e : to compare r e s u l t s from the standard s o i l ammonium e x t r a c t i o n method (Black, 1965b) and the blender method (Lauer et a l , 1976). to determine the e f f e c t of u t i l i z i n g 1N KC1 e x t r a c t i o n s o l u t i o n r a t h e r than recommended 2N KC1 s o l u t i o n (Black, 1965b) f o r e x t r a c t i n g ammonium from s o i l sample. to determine the b e n e f i t of u s i n g low pH e x t r a c t i o n s o l u t i o n d u r i n g b l e n d i n g . Procedure A. S o i l Sample P r e p a r a t i o n 50 ml of swine manure was poured on to the 400 gm of s o i l i n a 30 cm diameter t r a y (4 cm deep). Swine manure from the John V i e t s farm was used f o r t h i s study. The s o i l which was c l a s s i f i e d as B-horizon of s i l t y c l a y loam of Ladner s e r i e s , was o b t a i n e d from the Boundary Bay Water Management S i t e . The manure-soil sample was l e f t at room temperature f o r 24 hours and w e l l mixed before the a n a l y s i s . 89 B. A n a l y t i c a l Method 1. Standard s o i l ammonium e x t r a t i o n method. 10 g of manure sample was p l a c e d i n t o 250 ml f l a s k and mixed with 100 ml of 2N KC1. 4 r e p l i c a t e s were used f o r t h i s study. the f l a s k were p l a c e d i n shaker (New Brunswick S c i e n t i f i c , model no. G24) and shaked f o r 1 hour at the speed s e t t i n g of 250. the mixture was then c e n t r i f u g e d f o r 10 minutes at 3500 rpm (Western S c i e n t i f i c , H-103N s e r i e s ) and the supernatant was a n a l y s e d f o r ammonia d i r e c t l y on a Technicon Auto A n a l y s e r II (Technicon, 1973). 2. Blender Method 50 g of w e l l mixed manure-soil was p l a c e d i n a blender ( O s t e r i z e r b l e n d e r ) and 500 ml of 1N KC1 was added to g i v e 1:10 (wt/vol) suspension. the mixture was blended f o r 5 minutes, decanted i n t o a a i r - t i g h t p l a s t i c b o t t l e and kept i n the r e f r i g e r a t o r f o r 24 hours. the mixture was then c e n t r i f u g e d f o r 10 minutes at 3500 rpm and the supernatant was a n a l y s d f o r ammonia d i r e c t l y on a Technicon Auto An a l y s e r II (Technicon, 1973). 90 3. The procedure 2 was repeated but used 2N KC1 i n s t e a d of IN KC1 to e x t r a c t the ammonium from the sample. 4. The procedure 2 was repeated but added IN KCl s o l u t i o n which was s p i k e d with HC1 a c i d to b r i n g down the pH to 2.0. Results: 1. Standard Method No. of Samples Average Ammonia Content in Soil Sample (ppm) 412 + 14 2. Blender Method 3. 2N KCL Solution 4. Acidified Solution 406 + 13 430 + 19 424 + 17 

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