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Some physical characteristics and exposure loss estimates of pea vine silage in a horizontal silo Campbell, William Earl 1959

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SOME PHYSICAL CHARACTERISTICS AMD EXPOSURE LOSS ESTIMATES OP PEA VINE SILAGE IN. A HORIZONTAL SILO by WILLIAM EARL CAMPBELL B.S.A.(Hons.) University of B r i t i s h Columbia, 1953  A THESIS SUBMITTED II  PARTIAL FULFILMENT' OF  THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN AGRICULTURE i n the Department of AGRICULTURAL MECHANICS  We accept t h i s thesis as conforming to the required standard  THE UNIVERSITY OF BRITISH COLUMBIA A p r i l , 1959  i ABSTRACT Reports of large losses from exposed horizontal s i l o s under high f a l l and winter r a i n f a l l were investigated by f i e l d observation on a f u l l scale test s i l o .  Density, dry  matter, permeability and some proximate analyses of the silage are tabulated.  Observed dry matter losses i n order  of magnitude are fermentation losses, sub surface losses, surface losses, and losses i n runoff and effluent l i q u i d s . The value of these losses was computed.  The best method  of reducing the storage losses was a p l a s t i c sheet l a i d over the silage immediately after f i l l i n g and packing.  In p r e s e n t i n g the  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  requirements f o r an advanced degree at the  University  o f B r i t i s h Columbia, I agree that the  L i b r a r y s h a l l make  it  study.  f r e e l y a v a i l a b l e f o r reference  agree that  and  I further  permission f o r extensive copying of t h i s t h e s i s  f o r s c h o l a r l y purposes may  be granted by the  Department or by h i s r e p r e s e n t a t i v e s .  Head of  my  I t i s understood  that  copying or p u b l i c a t i o n of t h i s t h e s i s f o r f i n a n c i a l  gain  s h a l l not be allowed without my  Department  of  A g r i c u l t u r a l Mechanics  The U n i v e r s i t y of B r i t i s h Vancouver 8, Canada. Date  May  4, 1959.  Columbia,  written  permission.  ii TABLE OF CONTESTS Page  Introduction  ,  1  Literature Heview  1  Objectives of the Investigation  3  Materials and Methods Materials  3  Methods  4  Observations  11  Discussion  27  Conclusion  47  Literature Cited  49  Appendix  52  iii LIST OF TABLES Table 1.  Page  Summary of r a i n f a l l by months, 1957-58 and 1959  11  2.  Floor effluent summary by months, 1957-58  13  3.  Floor effluent summary by months, 1958-59  14  4.  "Wall" effluent summary by months, 1958-59  15  5.  Runoff summary by months, 1958-59  16  6.  Protein and ash i n dry matter from f l o o r e f f l u ent and runoff, 1958-59  16  7.  Pea vine and silage sample summary.  17  8.  Proximate composition of 1956-57 silage samples  18  9.  Proximate composition of 1958-59 silage samples  18  10.  Sub surface layer thickness during the storage period.  22  11.  Permeability of core samples, March 6, 1959  23  12.  Calculated storage losses and y i e l d s , 1958-59  25  13.  Percent dry matter surface l o s s , and y i e l d f o r grass silage exposed and covered by a p l a s t i c sheet, January 8, 1959.  26  14.  R a i n f a l l and t o t a l effluent collected by months, 1958-59 32  15.  Calculated l i q u i d balance September 1958 - March 1959 33  16.  Summary of dry matter losses i n effluent l i q u i d s , 1958-59  35  17.  Calculated dry matter balance September 1958 to March 1959  42  iv LIST OF FIGURES Figure  Page  1.  Plan and side elevation of l i q u i d c o l l e c t i o n system, 1957-58  4  2.  Layout of test area, 1957-58  5  3.  Silage sampling: t o o l  7  4.  F i n a l sampling t o o l  7  5.  Piezometer, showing construction  8  6.  Piezometer arrangement  9  7.  C o l l e c t i o n pan on v e r t i c a l face of silage  9  8.  Corer f o r permeability tests  10  9.  Permeability test arrangement  10  10. Method of f i l l i n g the s i l o  12  11. Silage after tractor packing August, 1957  12  12. Silage after tractor packing August, 1958  13  13. Surface conditions November, 1957  19  14. Surface conditions February, 1959  19  15. Surface conditions December, 1957  20  16. Appearance of exposed face, February 1958  24  17. R a i n f a l l and f l o o r effluent collected by months, 1957- 58 18. R a i n f a l l and effluent collected by months,1958-59 19. Dry matter losses i n effluent, by months, 1957-58 and 1958-59 20. Dry matter d i s t r i b u t i o n and y i e l d , 1957-58 and 1958- 59  30 31 34 44  V  APPENDIX Page A.  R a i n f a l l , 1957-58 season  53  B.  R a i n f a l l , 1958-59 season  55  C.  Effluent  flow from f l o o r area, 1957-58  57  D.  Effluent  flow, 1958-59  58  E.  Piezometer performance  63  F.  Permeability equation  64  vi  The author wishes to acknowledge the assistance given by the following individuals: Dr. J.C. Berry, Dr. V.C. Brink, Prof. T.L. Coulthard, and Prof. B.L. Watson.  Be also wishes  to acknowledge the cooperation of the Department of A g r i c u l t u r a l Mechanics, Division of Animal Science, and the D i v i s i o n of Plant Science.  -1INTROIXJCTION A number of enquiries by farmers i n the Fraser Valley suggested that high storage losses, p a r t i c u l a r l y i n drainage l i quids, occurred i n horizontal s i l o s exposed to r a i n .  Since  l i t t l e published work; was available on dry matter losses i n effluent from horizontal s i l o s exposed to high r a i n f a l l , a study of storage losses was  undertaken.  This work was not intended as a chemical or n u t r i t i o n a l study of silage or silage fermentation, but rather as an e s t i mate  of storage losses and physical c h a r a c t e r i s t i c s of silage  during the storage period.  I t was intended to provide data on  storage losses and suggest methods of keeping storage losses to  a minimum. LITERATURE REVIEW A r e l a t i v e l y large number of references were found on the  general topic of silage effluent losses, but nearly a l l r e f e r r ed only to effluent from tower s i l o s .  Only a few mentioned the  approximate dry matter losses i n the e f f l u e n t .  Barnett (3)  gives data on the composition of effluent from tower s i l o s and separates compression  losses from the fermentation losses.  He  also emphasizes the need f o r free drainage from tower s i l o s , to prevent the formation of unpalatable s i l a g e , even though s l i g h t ly higher dry matter losses were observed as a result of free drainage.  S i l l and Sears (17) reported that a roof reduced the  leaching losses i n tower s i l o s . Watson (19) gave some of the factors contributing to e f fluent loss i n tower s i l o s , including the water content and the silage pressures as variables, and noted that no leaching l o s s -  es occurred u n t i l a f t e r r a i n had f a l l e n on the s i l o .  Dry mat-  ter losses i n the effluent of a roofed tower s i l o were given as 1.5%,  and an estimate of losses i n effluent f o r roofed tow-  er s i l o s generally was  given as l e s s than 5% of dry matter i n -  put. Cooper et a l (7) reported storage losses i n small experimental s i l o s as 17.5% 14.5%  of input, and fermentation  (average of 2 years).  ed these losses to 4.5% losses of 32.4%  losses as  The use of p l a s t i c covers reduc-  and 5*5%  respectively.  Total silage  of input material were reported, but no expos-  ure conditions were given. Le Clerc (9) gave dry matter losses i n effluent from tower s i l o s as 47-82 pounds per one hundred gallons e f f l u e n t with the dry matter analysing 17-28% protein, 13-23% ash and amounting to an appreciable l o s s .  B l i s h (5) however, stated that  effluent losses f o r sunflower'silage  i n tower s i l o s were neg-  l i g i b l e , and noted that free drainage was  desirable to prevent  waterlogging and formation of sour s i l a g e . Waterson (18) reports that rainwater silage i n a horizontal s i l o may  soaking through the  cause secondary  fermentation  under the "slimed over" seal which forms after r o l l i n g packing of the silage surface.  and  Nash (18) states that a roof  i s required under S c o t t i s h conditions, and large losses have occurred i n unprotected s i l o s i n wet  years.  He reports that  maintenance of dry matter content i s important to maintain milk y i e l d , s t a t i n g that milk y i e l d s usually f a l l when low  dry  matter silage replaces high dry matter silage i n the r a t i o n . He also reports 20% dry matter silage as being l e s s than op-  timum dry matter. Density of silage has been reported i n some d e t a i l .  Otis and  Pomroy (14) reported very large variations i n silage density across the diameter of a tower s i l o . average l a t e r a l pressure  Esmay et a l (8) reported that  i n a horizontal s i l o was r e l a t i v e l y con-  stant with increasing depth, below two f e e t . OBJECTIVES OF THE INVESTIGATION The objective of t h i s i n v e s t i g a t i o n was to measure the magnitude and d i s t r i b u t i o n of losses due to seasonal r a i n f a l l on an exposed horizontal s i l o .  The volume and dry matter content of  the l i q u i d running o f f the surface, passing down along the walls and draining from the f l o o r of the s i l o was measured.  The den*-  s i t y and permeability of the silage was investigated, as these c h a r a c t e r i s t i c s could a f f e c t the leaching and surface losses. The changes i n t o t a l dry matter and dry matter percent of the silage over the storage period and the dry matter losses i n i n edible or unpalatable preventable  silage was measured.  The cost of the  storage losses was then used to determine what meth-  ods of protecting the surface were f e a s i b l e . MATERIALS AND METHODS Materials This investigation was conducted on pea vine silage since pea vine was a low cost, r e a d i l y available material which had shown high losses i n horizontal s i l o s .  Because i t was a r e l a -  t i v e l y coarse, unchopped material, i t was f e l t that i t would probably be quite susceptible to both surface losses and leaching.  -4-  Methods I t was assumed that the silage would behave very much l i k e a s o i l , where percolation i s primarily v e r t i c a l , and that hori z o n t a l flow i s n e g l i g i b l e except where Impervious layers i n terfered with normal v e r t i c a l flow.  I t was assumed that the  normal flow pattern i n silage would be runoff over silage surface toward the "toe" of the s i l o , and v e r t i c a l percolation of a r e l a t i v e l y small part of the r a i n f a l l to the s i l o f l o o r .  If  the drainage provided under the silage was not adequate to allow removal of the v e r t i c a l percolation, waterlogging could occur. In order to measure the volume and source of l i q u i d reaching the f l o o r of the s i l o , a test area f i f t e e n feet long was prepared near the ramp end of a f i f t e e n foot wide s i l o  (Fig.l).  r "Toe" silo  Floor  15'  of  Area >Wall D r a i n  To  15»—  s  Guard Length v Guard Ramp  Drain  Tanks  Percolation Test Pea  Gravel'  '--Floor Plastic  Length  Drains  •—,'  Guard Length .Guard  Drain.  Sheet  F i g . l . Plan and side elevation of l i q u i d c o l l e c t i o n system, 1957-58.  A c o l l e c t i o n system designed to allow separate c o l l e c t i o n of l i q u i d s from d i f f e r e n t areas was i n s t a l l e d .  Any effluent c o l l -  ected from the f l o o r area, f i f t e e n feet long and fourteen feet wide from wall drain to wall drain, was designated " f l o o r " e f fluent.  Any l i q u i d collected by the pipes l a i d p a r a l l e l to  the walls beside the f l o o r area was designated "wall" e f f l u e n t . Drain pipes were also i n s t a l l e d i n the seven foot long guard area at the ends of the test area to reduce "edge e f f e c t s " . The pea gravel and sand layer was intended to simulate a w e l l drained s i l o . Pig.  2 i s a picture of the s i t e before the c o l l e c t i o n  pipes were completely  covered.  F i g . 2. Layout of test area, 1957-58. A similar system was prepared i n 1958, and a p l a s t i c sheet long enough to extend the f u l l length of the s i l o was ed with a drain at the "toe" end of the s i l o .  install-  Any l i q u i d c o l l -  ected from this "toe" drain, combined with the l i q u i d from the guard area drains, was designated "runoff", since most of the l i q u i d came from surface runoff over the s i l a g e .  F i l l i n g of the s i l o was done c a r e f u l l y to prevent damage to the drainage c o l l e c t i o n apparatus. R a i n f a l l f o r the area during the period from f i l l i n g to the end of tests was obtained from the weather records of the Vancouver (U.B.C.) Station, located within one eighth of a mile from the s i l o . Samples of the f r e s h pea vine, effluent l i q u i d s and silage were taken.  Pea vine "grab" samples were taken as the s i l o  was  being f i l l e d and oven dried at 100°G f o r twenty-four hours or to constant weight.  E f f l u e n t samples were taken at the s t a r t  of effluent flow, and as required to follow changes i n percent dry  matter i n the e f f l u e n t .  The effluent samples taken p r i o r  to October 1, 1958, were oven dried at 70°G. E f f l u e n t samples taken a f t e r October 1st were dried under vacuum to reduce the charring noted i n oven dried samples.  Protein and ash analys-  es by A.O.A.C. methods were done on "runoff" and " f l o o r " effluent collected i n October and at the end of the exposure period. Silage samples were taken near September 1st and January 31st,  and as deemed neoessary from surface or feeding require-  ments.  Since the o r i g i n a l volume and weight of the samples  was known, the density was e a s i l y calculated. were oven dried to constant weight at 70°C.  Silage samples Proximate analys-  es of the September 1958 and March 1959, and some 1956-57 samples were done by A.O.A.C. methods. Successive silage samples were taken from selected adjacent undisturbed parts of the percolation test area of the  Fig,  3. Silage sampling t o o l .  Fig.  4. F i n a l sampling t o o l ,  A r e l a t i v e l y undisturbed s o l i d core, similar to the core i n the l e f t i n F i g . 3 can be obtained from silage up to s i x feet i n depth with the longer sampler used after December 1957 as shown i n F i g . 4.  The hole l e f t after sampling was packed f u l l  of silage from an adjacent  s i l o , to maintain the o r i g i n a l con-  d i t i o n s of density, moisture movement, and aeration during the storage  period.  For the purpose of t h i s study, to d i s t i n g u i s h fermentation and storage losses, the storage period was  defined a r b i t r a r i l y  as the period between one month from f i l l i n g to the end of servations.  The silage losses observed were separated  " s p o i l layer" losses and "sub face or " s p o i l layer" was  surface layer" l o s s e s .  ob-  into The  sur-  defined as the material above the  o r i g i n a l l y properly fermented s i l a g e , and included a p a r t l y decomposed surface layer, a slimy rotted layer which i s the actual seal layer, and a very t h i n p a r t i a l l y decomposed l a y er below t h i s seal l a y e r .  The "sub  surface" layer was  that  layer of material under the " s p o i l layer" which had been prope r l y fermented, but had subsequently been contaminated by surface products or had undergone other changes making i t unpal a t a b l e to c a t t l e .  LEAD  WIRE ANCHOR BLOCK  CONTACT WIRE  PLUG  F i g . 5. Piezometer, showing construction.  -9Several other experimental techniques were t r i e d .  Since ob-  servations i n 1957-58 suggested that the sub surface" layer n  might be saturated, e l e c t r i c piezometers which could indicate saturation were i n s t a l l e d at d i f f e r e n t depths i n the silage ( F i g . 5 and 6).  \>  yL fm  Floor 'j  10'  -*  10-  H  O  Ground h Rod 3^  !  w  Area  1  <  |  _"Toe 'of the silage "* Ditch and Dam for the "Runoff" System  .4  lie ads brought to the wall - Subscripts indicate depth i n feet F i g . 6. Piezometer  arrangement.  F i g . 7. C o l l e c t i o n pan on v e r t i c a l face of s i l a g e .  M  -13Another technique was  used to measure horizontal movement  of water i n the "sub surface" layer at the exposed face of the silage.  A c o l l e c t i o n pan one foot square was  fixed into the  v e r t i c a l face so that any effluent flow from the silage could he measured (Pig.  7).  S o i l permeability techniques were used to measure the perme a b i l i t y of core samples taken horizontally and v e r t i c a l l y from adjacent positions i n the silage (Pig. 8 and  COREP.  9).  -11Some other observations were made during the investigation. The unpacked depth after f i l l i n g , the packed depth, s e t t l i n g rates, surface conditions, " s p o i l " and "sub surface" layer depths and any other relevant information was recorded. Some observations and one p a i r of samples were drawn from an adjacent s i l o , one half of which was protected by a sawdust covered p l a s t i c sheet, to estimate the effect of the surface protection. OBSERVATIONS The r a i n f a l l , by months, from f i l l i n g to the end of observations, i s summarized i n Table 1, from Tables A and B i n the appendix. Month  R a i n f a l l In Inches 1957-58 1958-59  August  0.29*  1.86  September  1.16  2.16  October  3.24  4.26  November  3.67  7.29  December  6.72  8.11  11.25  6.78  5.77  5.74  32.10  36.20  January February Total  * records started August 20th. Table 1. Summary of r a i n f a l l by months from August to February i n c l u s i v e , 1957-58 and 1958-59. In both 1957 and 1958 the s i l o was f i l l e d and packed by a tractor equipped with a front end loader, which carried the mate r i a l into the s i l o from truckloads dumped nearby (Fig. 10). In 1957, the pea vine was very wet, as low as 15% dry matter, and  -12some showers occurred during f i l l i n g .  During packing, the com-  paction pressures under the wheels of the packing tractor were high enough to express moisture from the wet pea vine. vine packed s o l i d l y and showed l i t t l e "spring back"  The pea  ( F i g . 11).  In 1958 the pea vine was considerably d r i e r , averaging 21.7% dry matter, and did not pack w e l l . The surface remained r e l a t i v e l y loose even after packing ( F i g . 12). Showers just a f t e r packing did not improve the surface compaction.  Fig.  10. Method of f i l l i n g the s i l o .  Fig.  11. Silage after tractor packing August, 1957.  -13-  Fig.  12. Silage after tractor packing August, 1958.  The very wet pea vine ensiled i n 1957 started l o s i n g e f f l u ent almost immediately after f i l l i n g (Table 2 ) . The " f l o o r " effluent amounted to nearly one gallon per day the f i r s t ten days, then decreased to about two gallons per week f o r the next two weeks.  After September 5, " f l o o r " effluent losses were very  small . The percent dry matter i n the 1957 " f l o o r " effluent rose s l i g h t l y over the storage period. A summary of " f l o o r " effluent observations i s presented i n Table 2, from Table C i n the appendix. Month  Volume Gallons  August 14.69 September .75 October .75 November 1.60 December 2.30 January 50 Total 20.59 g a l . * estimated  Percent Dry Matter 3.72 4.05 4.35* 4.65* 4.95* 5.27  Dry Matter i n Pounds 5.5 .3 1.1 .2 8.1 lbs,  Table 2. Floor effluent summary by months, 1957-58.  The percent dry matter estimated f o r October, November, and Deeember were based on l i n e a r interpolation between September and January observed percent dry matter i n the f l o o r e f f l u e n t . The "wall" effluent was less than two gallons f o r the whole period from August 1st to January 31st and the "guard" effluent volume, though not measured, was observed to be very small. In 1958 effluent flow from the " f l o o r " area was n e g l i g i b l e u n t i l September 8.  From September 8 to September 28, a consid-  erable effluent flow was measured.  After September 28, only a  very small volume of effluent was collected as shown i n Table 3, summarized from Table D i n the appendix. Month August September October November December January February  Volume Gallons 0.1 29.33 4.5 .98 .84 .62 .46  Percent Dry Matter 10.7* 10.7 8.06 6.63 5.1* 3.7* 2.2  Total 36.83 g a l . * estimated  Dry Matter i n Pounds 0.1 30.9 .36 .06 .04 .02 .01 31.49 l b s .  Table 3. Floor effluent summary by months, 1958-59. A considerable volume of wall effluent was collected i n 1958, but the d i s t r i b u t i o n was very uneven (Table 4 ) . The connecting pipe to the measuring tank appeared to be plugging at i r r e g u l a r i n t e r v a l s , and e f f o r t s to keep i t operating d i d not make any difference to effluent flow.  A sudden very high rate  of flow was observed between October 13 and October 18, when 119 gallons of effluent was collected i n f i v e days.  Another  period of high flow r a tes occurred November 11 to 16th, a f t e r  -15which flow rates became almost uniform, with no sudden changes i n rate (Table 4).. Month August September October November December January February Total  Volume Gallons 1.40 3.20 121.0 57.85 12.0 32.5 73.2  Percent Dry Matter 10.0  Dry Matter i n Pounds 1.4 3.2 73.5 35.2 7.3 19.7  6.06 Use 6.06 as average  44-4  304.15 gal.  184.7 l b s .  Table 4. "Wall" effluent summary by months, 1958-59. The weight of dry matter i n the effluent was calculated using a value of 6.06$, which was observed during the period of maximum flow. In 1958 "runoff" was collected from the "toe" of the s i l o . This l i q u i d was collected from a t o t a l exposed area f o r t y feet long by f i f t e e n feet wide.  The volume of l i q u i d was high.  A  considerable amount of "runoff" was l o s t by overflow from the "toe"  area i f r a i n f a l l exceeded an average of 0.3 inches per  day f o r several days, and some l i q u i d was l o s t from the c o l l ection tanks overflowing.  Whenever possible, conservative est-  imates of the losses were made. The i n i t i a l high dry matter percent i n the "runoff", 10$ on September 1, dropped to 1.39$ October 13 and 0.53$ by February 4th.  The percent dry matter f o r lovember, December, and Janu-  ary were estimated by interpolation between the October 13th and February 4th observed percent dry matter i n the "runoff". This gives a dry matter loss about twenty-one pounds greater  -16than the product of observed "runoff" times average percent dry matter f o r the period October 13 to February 4 i n c l u s ive.  The observed dry matter losses were highest i n Aug-  ust and September, and were appreciable every month. Month  Volume o f "Runoff" 154.6 237.5 299.1 533.2 933. 748.6 404. 3310.0 g a l .  August September October November December January February Total * estimated  Percent Dry Matter  Dry Matter i n Pounds  10.0 5.7* 1.39 1.20* 0.96* 0.75* 0.525  154.0 135.0 41.2 64.0 89.0 56.1 21.2 560.5 l b s .  Table 5. "runoff" summary by months, 1958-59.  Dry matter from "runoff" and " f l o o r " effluent was analysed f o r protein and ash (Table 6). Sample Date Description  Oct. 13  Oct. 13  Runoff  Floor Effluent  Dry Matter per 100 g a l . M x 6.25$ Ash Percent Balance  13.9 31.4 22.2 46.4  80.6 27.2 24.0 48.8  Feb. 4 Runoff 5.25 26.0 38.2 35.8  Mar. 6 Floor Effluent 22.0 30.8 32.3 36.9  Table 6. Protein and ash i n dry matter from " f l o o r " effluent and "runoff", 1958-59. The t o t a l observed dry matter losses, August 1958 to February 1959, i n the effluent l i q u i d s are shown i n F i g . 19 i n the discussion. Silage samples were taken f o r observation during the  -17storage period both years.  A summary showing sampling dates  and physical characteristics of the samples i s given i n Table 7. Sample  Depth i n Inches  Dry Matter Percent of Wet Weight  Density (wet weight) l b . per cu. f t .  Dry Matter l b . per cu. f t .  19.3  47.3*  9.2*  20.1  48,6  9.8  0-6 6-18 18-30 30-42 42-52  17.2 19.0 15.0* 14.3 15.2 15.0 16.7  20.0* 27.8 39.7 57.5 45.0  3.0* 3.97 6.03 8.61 7.50  Average  15.3  39.7  6.05  0-12 12-24 24-36 36-41  21.7 23. 21.4 19.3 21.6  45.0** 11.0 34.3 48.1 43.2  9.8** 2.38 7.32 9.1 9.1  20.6  33.7  6.95  17.7 16.9 15.5 17.2  13.8 34.0 44.6 55.1 37.9 37.3 29.6 41.7 44.4 49.2  2.44 5.75 6.91 9.45 5.40  1956-57 Hov. 27 Jan. 14 l i - frozen 11  1957-58 July 29-30 pea vine Oct. 14 Jan. 28  1958-59 July 29-30 pea vine Sept. 3  Jan. 31  Average 0-12 12-24 24-36 36-40  av.3*** 16.4 av.2 5.83 15.7 Mar. 7 0-11 2.81 9.5 7.06 16.9 11-23.5 23.5 -35 15.5 6.69 15.8 35-39 7.79 Average 5.86 14.7 39.7 •estimated ••calculated from packed volume and t o t a l weight of packed s i l a g e , •••including samples from very s o f t , deeply rotted area Table 7. Pea vine and s i l a g e sample summary.  -18Proximate analysis of selected samples from 1956-57 and 1958-59 was done and the proximate composition observed i s l i s t e d i n Tables 8 and 9. Sample Date Nov.27,1956 Percent Dry Matter 18.7 Density 471bs. per cu,. f t . Dry Matter Analysis Protein 13.1 Pat 3.7 Fiber 30.7 Ash 11.8 N.F.E. 38.7 Silage Analysis (wet basis) Protein 2.3 Fat 0.7 Fiber 5.7 Ash 2.6 N.F.E. 6.9  Jan. 14» 1957 20.2 48.71bs,. per c u . f t . 13.2  3.8  30.4  10.3 42.3  2.7 0.8 6.2 2.3 8.7  Table 8. Proximate <composition of 1956-57 silage samples. Sample Date Percent Dry Matter Density Dry Matter Analysis Protein Fat Fiber Ash N.P.E. Silage Analysis (wet Protein Fat Fiber Ash N.F.E.  Sent.3.1958 20.6 33.7 9.8  2.9  Jan.31.1959 16.4 37.3  9.3 3.4  24.6  25.8  17.5  17.5  45.2 basis) 2.01 0.60  5.06 3.62 9.34  43.7  Mar.6.1959 14.7 39.7  9.4  3.4 26.4 18.0 42.8  1.52 0.56 4.23 2.88 7.17  1.38 0.50 3.89 2.65 6.30  Table 9. Proximate composition of 1958-59 silage samples from percolation test area. The silage depth decreased between packing and the end of the storage both seasons.  In 1957-58, the silage settled about  three inches i n the f i r s t month, and a further three inches following a period of heavy r a i n Movember 10-14th. s e t t l i n g i n 1957-58 was f i v e to s i x inches.  The t o t a l  In 1958-59, con-  -19siderably more s e t t l i n g occurred.  S e t t l i n g between August 1  and September 3 was approximately  f i v e inches, and from Sept-  ember 3 to February 1 f i v e inches, f o r a t o t a l of ten inches from f i l l i n g to feeding.  The silage along the walls settled  two to f i v e inches more than the silage i n the middle of the silo. Observations  of the ensiled material after f i l l i n g sugg-  ested that considerable losses occurred, both i n 1957 and 1958 (Fig. 13 and 14).  Fig.  Fig.  13. Surface conditions November, 1957.  14. Surface condition February, 1959. Metal piezometer tags can be seen on the silage surface.  -20Surface changes after f i l l i n g were s l i g h t l y d i f f e r e n t i n 1957 and 1958.  In 1957, the very wet pea vine packed t i g h t l y  right to the surface, and a d e f i n i t e seal layer formed within a week.  The exposed silage above the seal layer dried out  somewhat, and the seal layer increased three weeks.  i n depth f o r about  By September 1, the t o t a l " s p o i l " layer averag-  ed about s i x inches deep. The " s p o i l " layer appeared almost impervious to water. Surface water from r a i n f a l l remained i n depressions on the surface almost continuously from November 12th u n t i l the end of the test.  Some surface mold and plant growth i n the " s p o i l " layer  started i n l a t e November(Fig. 15)•  F i g . 15. Surface condition, December, 1957. The f i n a l depth of the " s p o i l " layer varied from four to eleven inches and averaged about seven inches on January 28, 1958. The d r i e r , less t i g h t l y packed pea vine ensiled i n 1958 developed a r e l a t i v e l y deep, incompletely rotted layer within  a week a f t e r packing.  This seal layer was about f i v e  inches  thick, under a two inch surface layer of dried pea vine. This seal layer did not prevent some further decomposition of the silage under i t , and by September 3, the " s p o i l " layer was eight inches deep.  A t h i n layer of very hot, r o t t i n g s i -  lage was observed at the bottom of the " s p o i l " layer, where the temperature was 110°F.  This r o t t i n g layer had cooled o f f  completely by October 6, and appeared as a greyish paste l a y er about one h a l f to one inch deep.  The " s p o i l " layer depth  was s t i l l eight inches October 6 and January 31. The f i n a l " s p o i l " layer depth March 6 ranged from f i v e to eleven  inches  and averaged eight inches. As i n 1957-58, the " s p o i l " layer was very wet, and often had water l y i n g i n the surface depressions after heavy r a i n s .  f o r several days  Mo plant growth was observed on the s i -  lage surface. In both years another layer of material which could not be used developed under the " s p o i l " layer during the storage period.  This "sub surface" layer was n e g l i g i b l e i n early  September, and the normal t r a n s i t i o n from "slimy" seal materi a l , through partly rotted, dark material, to l i g h t o l i v e green silage usually took place i n one inch or l e s s of depth. With Increasing storage time, a d e f i n i t e layer of darkened, sour or moldy smelling silage was observed, under the " s p o i l " layer(Table 10). This "sub surface" layer had a d e f i n i t e top boundary of partly rotted silage i n the " s p o i l " layer, but the lower  boundary was  less c l e a r l y defined.  The colour and odour of  tne material gradually changed to that of palatable s i l a g e over a depth of two to four inches, so the actual depths given were a r b i t r a r y . Date Sept. 1-3  1957-58 Percolation "Toe" Test Area Area* 0 0  Oct. 13  1"  4"  Jan.28-31 Mar. 6  3"  12"  1958-59 Percolation "Toe" Test Area Area** 0 1" 1"  1-3"  4-8" 6-8" * 30 feet from percolation t e s t area ** 20 feet from percolation t e s t area  8" 10"  Table 10. Thickness of the "sub surface" layer during the storage period. The investigation of saturation i n the "sub surface" l a y er using e l e c t r i c piezometers was unsuccessful, and no conclusive saturation condition was  revealed  (Table B).  Observation of the exposed end of the silage during feeding i n 1957-58 showed some l i q u i d was draining from the v e r t i c a l face of the s i l a g e . The l i q u i d appeared to be coming primarily from the darker "sub surface" layer, and no measurable flow occurred from the light-coloured s i l a g e . The l e c t i o n of horizontal flow from the v e r t i c a l face of the  col"sub  surface" layer i n March 1958 showed a measurable flow occurred.  This flow was  estimated to be not less than twenty-two  gallons through the "toe" end of the "sub surface" layer during the storage  period.  Pairs of core samples f o r permeability tests were taken from near the f l o o r of the s i l o .  V e r t i c a l cores could be  taken at any depth, but undisturbed h o r i z o n t a l cores could only be taken from the r e l a t i v e l y dense, uniformly packed s i lage.  The f i r s t pair of core samples were from a section  where the silage was tangled, and the horizontal core obtained gave exceptionally high permeability values (Table 11). Core Direction Description Diameter  #1 #2 vert. horiz. paired with #2 3.188" 3.188"  #3 #4 #5 vert. horiz. vert. #4 paired with #3and #5 3.188" 3.188" 3.188"  Length Head Volume per hr. Calculated K Density  6.125" 1" 24cc.  3.5" 1/2" 6720cc.  5.&9" 1/4" 408cc.  .10  30.4 46.1  Ratio %  :%  Average EU £ Average Ky  304  2.3 44.2  5.69" 4.81" 1/4" 1/4" 1065cc. 37.5cc. 6.0 45.3  2.6  .21 29.6  _ 21*1 *L,x  Table 11. Permeability of core samples, March 6,1959. The horizontal and v e r t i c a l permeabilities, Kg and  re-  spectively were calculated from the relationship Q= A K i , where i , the hydraulic gradient = h, the head d i f f e r e n t i a l divided by L, the length of the sample through which the water moves(,Appendix F ) . Some other observations were made after the s i l o was open ed to the c a t t l e .  In 1957, 1958, and 1959, the c a t t l e showed  strong preference f o r silage from some areas of the feeding face.  Some silage, was rejected completely while adjacent s i  -24lage was  eaten up to the l i m i t of a v a i l a b i l i t y  ( F i g . 16).  F i g . 16. Appearance o f exposed f a c e , February, In most cases the r e j e c t e d s i l a g e was c o l o u r , and appeared very wet.  1958.  s l i g h t l y darker i n  There was no d i s c e r n a b l e d i f -  ference i n s m e l l between acceptable and unacceptable  silage  i n most cases, but some r e j e c t e d s i l a g e d i d s m e l l s l i g h t l y moldy.  The unacceptable areas ranged r i g h t from f l o o r  to the base of the "sub s u r f a c e " l a y e r . appeared  The r e j e c t e d  level silage  somewhat l i k e the m a t e r i a l i n the "sub s u r f a c e "  l a y e r i n some p l a c e s . The p o s i t i o n of the r e j e c t e d s i l a g e areas was  apparently  random at any one time, but as the exposed f a c e advanced duri n g f e e d i n g , these areas tended to i n d i c a t e i r r e g u l a r volumes along the l e n g t h of the s i l o .  The arrangement o f the s i l a g e  remaining i n the r e j e c t e d areas suggested t h a t these areas occurred between the separate f o r k loads of pea v i n e f i l l e d i n t o the  silo.  -25The f i n a l t o t a l dry matter y i e l d i n 1957-58 was calculated from estimated dimensions and observed density f i g ures, since exact weight i n the test s i l o was not known. The maximum dry matter y i e l d of palatable silage was calculated as 35%, and the minimum as 25%, depending on the exact weight and average percent dry matter of the input material for the whole s i l o .  The calculated " s p o i l " plus "sub sur-  face" layer loss was estimated at between 6% and 8.5% of the t o t a l input dry matter. The calculated storage losses and y i e l d s , f o r the 195859 season are given i n Table 12. Weight of silage put into the s i l o ........ 130,5501bs. Dry matter 21.7% of wet weight. T o t a l dry matter input  28,3001bs.  Sept. 3,1958 Pounds Percent of input Total dry matter 11,800 loss of dry matter Dry matter i n " s p o i l " layer 830 Dry matter i n "sub surface" layer 110 Net edible dry matter 10,860 Loss of edible dry matter during storage period  41.7  Mar. 6,1959 Pounds Percent of input 9,700  34.3  2,100  7.4  2,9  1,010  3.6  0,4  2,400  8.5  38.4  6,290  22.2  4,570  16.2  Table 12. Calculated storage losses and y i e l d s , 1958-59.  Observation of grass silage i n an adjacent s i l o with one h a l f i t s length covered by a p l a s t i c sheet and held down with four inches of sawdust were also made.  The surface loss was  n e g l i g i b l e under the p l a s t i c sheet but amounted to about s i x inches i n the unprotected s i l a g e .  However, the t o t a l depth  of silage adjacent to the p l a s t i c sheet was two inches less than the depth under the sheet, and the t o t a l dry matter per square foot of surface was only f i v e sixths as great as the t o t a l dry matter per square foot under the p l a s t i c sheet (Table 13). Silage from protected area Percent dry matter Average density pounds per c u . f t . Dry matter per c u . f t . i n pounds Dry matter, pounds per sq. f t . of surface Surface l o s s , pounds per sq. f t . of surface Net dry matter, per sq. f t . of surface Comparative y i e l d of dry matter Table 13.  Silage from exposed area  21.2  19.4  37.6  35.0  7.96  6.78  35.4  31.6  0  1.7  35.4  29.9  6  :  5  Percent dry matter, surface l o s s , and y i e l d f o r grass silage (a) exposed and (b) covered by a p l a s t i c sheet, January, 1959.  One effect of the p l a s t i c sheet was undesirable.  Since  most of the r a i n f a l l ran towards the w a l l of the s i l o and the p l a s t i c sheet was not carried up the wall at a l l , a large volume of water was s p i l l e d into the silage near the w a l l . A d e f i n i t e loss by molding and r o t t i n g occurred along the walls. This can e a s i l y he prevented by extending the p l a s t i c sheet  -27up the wall about s i x inches. The cost of p l a s t i c sheets f o r use as s i l o covers was $,02 per square foot.  The f i f t y foot by t h i r t y foot sheet which  was used i s i n f a i r l y good condition, and can be reused a f t e r repairs estimated at $5.00,  I t s useful l i f e i s estimated as  two or three years. The cost of applying, covering, and removing the p l a s t i c sheet were not known, but were estimated as comparable t o , or s l i g h t l y less than, the cost of stripping the " s p o i l " and "sub surface" layers from pea vine s i l a g e . Pea vine cost $5.00 per ton delivered, to the s i l o .  The  t o t a l pea vine ensiled i n 1957-58 was 397 tons i n two s i l o s , and i n 1958-59 65.2 tons.. DISCUSSIOM Samples taken by the core sampler were used whenever possible to provide data f o r density calculations.  The den-  s i t i e s so obtained are probably less accurate than cubic foot examinations, since the samples are smaller and more subject to l o c a l v a r i a t i o n .  Otis and Pomroy reported t h e i r  four inch core sampler gave density values s l i g h t l y lower than cubic foot sampler values (14). The f a c t that impact must nearly always be used suggests some error may be i n t r o duced into both density and moisture determinations by water loss caused by the impact pressure.  Por this reason a l l  samples were taken with as nearly i d e n t i c a l procedure as possible, and cores were removed a f t e r each foot of depth had been penetrated as estimated from sampler penetration and checked by measurement of the hole depth.  Errors i n  -28surfaee density due to trampling etc. were not compensated f o r , but a minimum of inspection and sampling i n the percol a t i o n test area was done from September to February to keep these errors to a minimum. The density calculated from cores from the deep sampler (Fig. 3) was compared to the density of short cores, from the same location made with the permeability corers and showed good agreement, 44.4 and 45.2 l b s . per cubic foot respectively. The " f l o o r effluent" collected from the " f l o o r " area each season was very small compared to t o t a l r a i n f a l l ( F i g . 17 and 18).  In 1957 the very wet material l o s t two thirds of the  t o t a l " f l o o r effluent" collected i n the f i r s t month, before any s i g n i f i c a n t r a i n f a l l occurred.  The r e l a t i v e l y dry pea  vine ensiled i n 1958 did not show an appreciable l i q u i d loss u n t i l after at least two inches of r a i n had f a l l e n on the s i lage surface.. The r e l a t i v e l y small loss of l i q u i d from the f l o o r drainage system i s emphasized when the t o t a l collected " f l o o r effluent" f o r 1957-58 over s i x months, was equivalent to inches or .55$ of the t o t a l r a i n f a l l .  This compares to  0.17 0.31  inches or 0.8 per cent of the t o t a l r a i n f a l l i n the 1958—59 season when a s l i g h t l y shallower silage mass was  present.  In 1957-58, the amount of "wall effluent" collected negligible after August 3.  was  The amount collected i n 1958-59  was appreciable, and showed a flow rate similar to the r a i n f a l l graph u n t i l October 17th.  Then and p e r i o d i c a l l y during  -29-  the remainder of the storage period the "wall effluent" flow became e r r a t i c and unpredictable.  Apparently an a i r lock  formed somewhere i n the wall drain l i n e , perhaps due to gases produced by fermentation i n the l i q u i d during periods of slow drainage.  E f f o r t s to blow out the l i n e by a i r pressure  and  to f i l l up the l i n e s with water did not prevent recurrence of the apparent blockage.  After the l i n e was dug up and r e -  buried i n December the "wall effluent" flow was more even, but never attained the high values observed i n early October. I t i s possible that overflow from the wall area may have influenced the " f l o o r " effluent volume, but since r e l a t i v e l y small volumes are involved, no serious errors should r e sult even i f some interchange occurred.  There was  quid loss through the wooden walls of the s i l o . surface was  some l i -  The silage  sloped more steeply towards the sides than to-  ward the low end of the s i l o , and the silage depth along the walls was uneven.  Considerable surface runoff went to the  wall and was unable to run p a r a l l e l to the wall towards the "toe" and "runoff" c o l l e c t i o n l i n e s .  Some leakage was  ob-  served along the unbacked north w a l l , but no leakage was evident through the earth hanked south w a l l .  Ho estimates  of  t h i s loss were made. The "runoff" and end guard area drains were combined since guard area volume was assumed to be too small to a f fect the "runoff" volume appreciably.  The observed "runoff"  was related to r a i n f a l l , but only accounted f o r from 30-49 percent of the observed r a i n f a l l (Table 14).  I i i > o  17, R a i n f a l l and F l o o r E f f l u e n t by Months, 1957-1958  Collected,  0  1  Augo  Septp  1  1  1  1  1  Oct.  Nov.  Dec.  Jan.  Feb.  Fig.  1 8 . R a i n f a l l and E f f l u e n t by  Rain i n Inches  Months,  Collected,  1958-1959.  Effluent i n Gallons  Augc  Sept.  Oct.  Nov.  Dec.  Jan.  Feb.  -32Month  Rainfall i n gallons  Total effluent i n gallons  August September October November December January February  490 550 1130 1940 2160 1805 1530  156 270 425 592 946 782 479  Total  9605  3650  Percent of rainfall collected 31.8 49.1 37.6 30.5 43.8 43.4 31.1 38.  Table 14. R a i n f a l l and t o t a l effluent collected by months, 1958-59. Ponding i n the dam at the "toe" of the s i l o tended to average out the d a i l y r a i n f a l l readings by allowing a carryover from day to day or while the tanks were being drained.  Drain-  ing had to be done by hand pump or compressed a i r , when the water l e v e l i n the f i e l d drains was high enough to prevent gravity drainage of the tanks.  Maximum capacity of the run-  off c o l l e c t i o n system was about 130 gallons per day f o r three f i l l i n g s and three drainings at s i x hours per cycle.. This was equivalent to about 1.0 inches of r a i n i n two days.  At  the start of the winter t h i s was f e l t to be adequate, as the surface roughness of the s i l o delayed surface runoff considerably.  However, t h i s capacity was found to be inadequate  for the highest observed r a i n f a l l s ,  and estimates of the v o l -  ume flowing over the dam were made to compensate f o r t h i s loss. No calculations of evaporation loss were made because low mean temperature  and high humidity prevailed through  most of the storage period and evaporation losses were therefore assumed to be small.  A l i q u i d balance f o r the 181 day storage period from September 3, 1958 to March 6, 1959 revealed a 4541 gallon shortage i n the t o t a l volume of l i q u i d measured compared to calculated volume of water i n r a i n f a l l on the s i l o f o r the same period.  This unmeasured l i q u i d was 49.8 percent of the t o t a l  r a i n f a l l during the storage period (Table 15). Total r a i n f a l l 34.34 inches  9115 g a l .  Total i n effluent  3494 g a l .  Retained i n silage  1080  Total measured  4574  Not measured  4541  Total  9115 gal.9115 g a l .  Percent of t o t a l r a i n f a l l not located  Table 15.  49.8%,  Calculated l i q u i d balance September 1958March 1959.  A part of the l i q u i d loss was overflow from the c o l l e c t ion tanks.  Other small losses, occurred by wall leakage, but  these were not considered to be appreciable. of error i n the l i q u i d c o l l e c t i o n  The main source  system was the inadequate  capacity of the "runoff" measuring system.  Sustained heavy  r a i n t o t a l l i n g more than 1,0 inches per forty-eight hours overloaded the "runoff" c o l l e c t i o n  system so that a large  part of the ensuing runoff overflowed and was l o s t .  Por t h i s  reason, the t o t a l uncollected l i q u i d was assumed to be "runoff" . The dry matter losses i n the effluent from September 3, 1958 to March 6, 1959 are summarized i n Table 16.  F i g . 19. Dry Matter Losses i n E f f l u e n t 19b7-58 and 1956-59  by Months,  200 Dry Matter i n " W a l l " Monthly Dry  Effluent  Dry Matter i n " R u n o f f " 150  Dry Matter i n " F l o o r "  Effluent  Matter l  Losses In  I  LOO  Pounds v • /.  50+ //A  /57  /58  Aug.  /57  /58  Sept.  /57  /58  Oct.  /59  /58  Nov.  /57  /58  Dec.  /57  /58  /58  Jan.  Feb,  -35Effluent  Dry Matter i n Pounds  Floor effluent  Percent of Input Dry Matter  31.4  0.11  Wall effluent 183.3 Runoff (measured) 406.5 Total calculated dry matter 621.2 Runoff (estimated) 650. Total estimated dry matter loss i n e f fluent 1271.2  0.65 1.45 2.21 2.3 4.5  Table 16. Summary of dry matter losses i n effluent l i q u i d s , 1958-59. The t o t a l dry matter i n the measured effluent during the storage period was 621.2 pounds, or 2.2% of the input dry matter.  The estimated l i q u i d not collected, at the October  dry matter content of 1.39%, was calculated to contain 650 pounds dry matter or 2.3% or input dry matter.  The correct-  ed dry matter loss f o r the storage period was 1271 pounds or 4.5%. The dry matter losses i n the " f l o o r " effluent were f o r an area of 210 square feet of the 504 square feet of the tota l f l o o r area.  The"wall"effluent came from 30 feet of the  72 foot wall length.  The corrected  losses f o r the whole  " f l o o r " and "wall" areas respectively, were 0.27% and 1.55% of the input dry matter.  These corrections do not a f f e c t  the t o t a l dry matter loss as this dry matter was theoretica l l y collected i n the "runoff" l i q u i d .  Total estimated dry  matter losses i n effluent from August to February inclusive were 1286 pounds or 4.55 percent of input dry matter.  -36The protein and ash i n the " f l o o r " effluent and "runoff" was considerably higher than the reported protein and ash f o r effluent from tower s i l o s (9). The protein remained f a i r l y constant at 26-31% during the storage period, and was lowest i n the dry matter from "runoff" l i q u i d i n February (Table 6). This i s above the 17-28% range given f o r dry matter i n e f f l u ent from tower s i l o s .  The percent ash i n dry matter i n Oct-  ober was nearly equal at 22.2 and 29.0% i n "runoff" and " f l o o r " effluent respectively, and near the top of the range of 13-23% reported f o r dry matter i n effluent from tower s i l o s .  At the  end of the storage period the ash content was 38.2 and 32.3% respectively f o r the dry matter i n "runoff" and " f l o o r " e f f l u ent. The t o t a l loss of protein i n the effluent dry matter was estimated as 372 pounds or nearly 9% of the estimated 4200 pounds protein i n the pea vine.  For ash, the t o t a l loss i n the  effluent was estimated as 370 pounds or 18% of the estimated 2100 pounds ash i n the pea vine.  This r e l a t i v e l y important loss  was more important than the small t o t a l dry matter loss of 4.5%. This was similar to reports by Watson (19) that 4% of mineral and 3.5% of protein were contained i n l e s s than 1.5% of the t o t a l dry matter l o s t as effluent from a tower s i l o . I t i s i n t e r e s t i n g to note that the "runoff" from the end of the s i l o September 3rd had very nearly the same dry matter eontent, 10.0%, as the "wall" e f f l u e n t , 10.7%. was i n s u f f i c i e n t f o r sampling.  The " f l o o r e f f l u e n t "  This suggests that l i t t l e dry  matter loss due to r a i n had occurred p r i o r to September 2rd. This contrasts with the percent dry matter on October 13, when "run-  -37off" contained 1.39 percent, "wall" effluent 6.06 percent and " f l o o r " effluent 8.06 percent dry matter a f t e r approximately four inches of r a i n had f a l l e n onto the s i l a g e . The d i s t r i b u t i o n of the dry matter losses i s indicated i n F i g . 19. The very high dry matter losses i n September "runoff" are due to the high observed percent dry matter, and moderate volume, not to a large volume of e f f l u e n t . The November, December, and January "runoff" dry matter came from larger volumes of effluent and much lower percent dry matter contents. The silage samples taken at d i f f e r e n t times over the s t o r age period showed some changes i n composition with time.  Dur-  ing 1958-59 the r e l a t i v e l y small decreases i n protein, and N.F.E., and r e l a t i v e l y small increases i n f a t , f i b e r , and ash on a dry basis were not as important as the general decrease on a wet basis of a l l constituents with increasing water content over the storage period.  The reduction i n the quality  of the silage was primarily a reduction i n the dry matter available per one hundred pounds of s i l a g e , which decreased from 20.6 pounds on September 3rd to 14.7 pounds on March 6th. The r i s e i n percent dry matter observed i n 1956-57 was due at least i n part to an i c e layer on the surface of the s i l o for some weeks, so that l i t t l e water was able to get into the silage, and probably i n part to v a r i a t i o n i n the material. The silage samples also showed some changes i n density with time and depth.  The observed density of the silage i n -  creased with both increasing depth and increasing time (Table 7).  In a l l cases the surface density was the lowest.  -38The increase i n density with depth was associated with higher dry matter content per cubic foot i n almost a l l cases. However the increase i n density with time i s primarily an increase i n water content, with the actual average dry matter i n pounds per cubic foot decreasing with time.  The aver-  age dry matter per cubic foot could be expected to decrease s l i g h t l y , as the decrease i n volume over the storage period was r e l a t i v e l y small, and the calculated dry matter losses i n the t o t a l collected effluent l i q u i d s totaled 0.35 pounds per cubic foot of s i l a g e . The storage losses observed were over a storage period of about 180 days which i s comparable to farm p r a c t i c e . The most prominent loss was i n the " s p o i l " layer, but i n fact this loss was almost constant over the storage period (Table 12).  The increase i n the surface loss over the storage per-  iod as a percent of the t o t a l input dry matter was only 0.7 percent i n 1958-59.  The t o t a l " s p o i l " layer loss on March  6th was 3.6 percent as compared to 2.9 percent on September 3rd, only one month from f i l l i n g .  This layer showed consid-  erable v a r i a t i o n i n depth from area to area, but the v a r i a t i o n did not form any predictable pattern. The most important dry matter loss during the storage period was i n the "sub surface" l a y e r .  This layer was neg-  l i g i b l e or indistinguishable on September 3rd, but amounted to 2400 pounds or 8.5 percent of the dry matter input by March 6, 1959.  The storage losses from September 3rd to  March were "sub surface" layer 8.5 percent, observed dry matter i n effluent 2.2 percent, estimated dry matter i n  -39unmeasured effluent 2.3 percent, and " s p o i l " layer loss of 0.7 percent.  The t o t a l exposure loss d i r e c t l y attributable  to exposure f o r 180 days was 8.1 percent i n "sub surface" layer, 7.4 percent i n dry matter l o s t from the s i l a g e , and 0.7 percent i n surface loss or 16.2 percent of input dry matter. The 1957-58 observations suggested that the "sub surface" layer was formed by l i q u i d from the surface contaminating the silage under the " s p o i l " layer with decomposition products, and perhaps changing the conditions of aeration, water content, and even acidty to the point where secondary fermentation occurred.  The depth of the "sub surface" layer  increased toward, the "toe" of the s i l o , and was least i n the area around the highest point of the s i l o surface.  The  thickness of t h i s layer also increased with time, but the thickness at the "toe" end of the s i l o was always greater than at the upper end. The 1958-59 observations are similar to the 1957-58 observations.  The "sub surface" layer developed only a f t e r at  least four inches of r a i n had f a l l e n , and increased i n depth with time, and toward the "toe" of the s i l o .  I t also i n -  creased i n thickness s l i g h t l y toward the walls, as the slope toward the walls was greater than the slope toward the "toe" of the s i l o . urred.  Relatively large variations i n thickness occ-  One very dense hump i n the s i l o had less than three  inches of "sub surface" layer l o s s , while a low area along the wall near the "toe" had nearly eighteen inches loss f o r several f e e t .  The development of the "sub surface" layer  -40appears to be related to the amount of water passing through the " s p o i l " l a y e r and into the s i l a g e , and to the mode of water  movement. The use of e l e c t r i c piezometer c e l l s to t r y to detect  saturation of the mass, p a r t i c u l a r l y the "sub surface" layer, appears to he a useful t o o l f o r further moisture studies, a l though they were not too satisfactory i n t h i s study.  The  p r i n c i p l e i s satisfactory and responses are fast (Table E, appendix). Failures were apparently caused by minute cracks i n the p l a s t i c insulation on the wires, which allowed the silage l i q u i d to contact the wires.  The small area of contact and  of conducting f l u i d kept the reading much lower than that of a submerged c e l l , but allowed a small "leak" reading. The ammeter readings were related to the distance between the test c e l l and the ground rod, but t h i s v a r i a t i o n was small and did not interfere with other readings.  The area  of electrode i n contact with the silage i s more important than the spacing from c e l l to ground electrode, but t h i s area could be e a s i l y increased i f necessary.  Scale readings  decreased f a i r l y rapidly a f t e r about two seconds of current flow, apparently as a r e s u l t of polarization of the e l e c t rodes.  The o r i g i n a l maximum reading could be duplicated  after waiting about two minutes, or by reversing the polari t y of the system, or by very short successive reading i n tervals.  This " f a l l i n g o f f " of the scale readings did not  interfere with separation of c e l l saturation and "leak" readings.  -41Although the piezometer c e l l s did not indicate saturation at the twelve inch l e v e l , a measurable volume of effluent was collected from the v e r t i c a l face of the "sub surface" layer at the "toe" end of the s i l o .  This estimated flow, 22 g a l l -  ons over 180 days, i s very small, and i s hardly enough to account f o r the s p o i l i n g of 2400 pounds of s i l a g e .  It i s  probable that much higher flow rates exist at certain places over the v e r t i c a l face, and that some higher flow rates may be observed at different times as r a i n f a l l v a r i e s .  This small  flow, was calculated from the very conservative assumption that the flow rate observed was twice the average flow rate, and that the average conducting area of the "sub surface" layer was one h a l f the f i n a l end area of f i f t e e n square f e e t . This flow was nearly as great as the t o t a l flow from the two hundred and ten square foot " f l o o r " area. Since the p o s s i b i l i t y that appreciable horizontal flow occurred had been suggested i n 1957 by observations at the exposed v e r t i c a l face, some tests of horizontal and v e r t i c a l permeability were done. The values of permeability i n a h o r i z o n t a l d i r e c t i o n (Kg) were i n every case higher than the values f o r v e r t i c a l permeability (Ky.) through the mass (Table 11).  The f i r s t  pair of samples gave extremely different values of K^ and K^.. The very high K^ was probably due to channelling i n the horizontal core sample, which was d i f f i c u l t to get without damaging the silage structure. The next set of samples s t i l l had a considerable v a r i a t i o n between the Kg values. A l l the Kjg; values were larger than the largest K^- value. The  -42average K^ to average Ky r a t i o i s 21 : 1. Since the K value i s a measure of the rate of flow of water through a mass, a high K value indicates high possible flow rates.  The Kg to Kg r a t i o indicates that water w i l l flow  horizontally more readily than i t w i l l v e r t i c a l l y under the same hydraiulic head.  The development of the "sub surface"  layer, which increases i n depth with increasing storage time, and also increases i n depth towards the "toe" or low end of the s i l o can apparently be explained i n part by the Kg ^ (  Kg r a t i o .  Considerably more work could be required to es-  t a b l i s h a d e f i n i t e relationship between the shape of the "sub surface" layer and the observed Kg to Kg r a t i o s . The cores used f o r the K determinations were taken from the t h i r t y inch depth, since t h i s was the only l o c a t i o n at which a satisfactory horizontal core could be obtained. %  The  to Kg relationship i s probably less d e f i n i t e as the den-  s i t y of the silage decreases, and may not, i n f a c t , be determinable by t h i s technique i n the " s p o i l " and "sub surface" layers. A dry matter balance from September 3 to March 5 showed f a i r agreement (Table 17) September 3, 1958 March 6, 1959 Total estimated dry matter i n effluent Not accounted f o r  Calculated Dry Matter i n PoundP 11,800 9,700 11,800  1.271 10,971 829  Table 17. Calculated dry matter balance, September 1958 to March 1959.  -43The calculated dry matter loss from the s i l o over the storage period, as given by the difference i n dry matter i n the September 3 and March 6 samples, was 2100 pounds or 7.4 percent of the input dry matter.  The dry matter not accounted  for i n the effluent during the storage period, was 829 pounds, or 2.9 percent of the input dry matter.  There i s no way of  demonstrating whether the whole 2100 pounds of calculated dry matter l o s t from the silage was a l l i n the effluent  li-  quids or whether some dry matter was l o s t by surface oxidat i o n and decomposition.  The presence of the very hot, almost  ash l i k e layer under the " s p o i l " layer i n September suggests surface losses may have contributed to the storage dry matter l o s s . 1957-58 observations showed a moderate " s p o i l " plus "sub surface" loss during storage and a negligible dry matter loss i n l i q u i d collected from the " f l o o r " area.  More data on dry  matter content i n the s i l o i n September 1957 would be needed to accurately measure the dry matter losses.  The maximum  net y i e l d and the maximum dry matter at the end of the storage period, as estimated from photographs and other data, was 35 percent and 40 percent respectively, of the t o t a l dry matter input (Fig. 20). The net dry matter y i e l d from the 65 tons of pea vine s i lage was approximately 6290 pounds or 22,2 percent of the t o t a l dry matter delivered to the farm.  The net dry matter  y i e l d on September 3 was 38.4 percent of the gross dry matter input.  Total losses i n the f i r s t month by fermentation  and surface losses were calculated as 61.6 percent as com-  100  T  Fig.  HQ.  Dry M a t t e r D i s t r i b u t i o n and 1957-1958 and 1958-1959.  Yield,  Percent of 80 '\\\  Input Dry Matter 60  Estimated MaXo Total Dry Matter  "Spoil"  "Sub s u r f a c e " Net  Edible  /5c Filling  /57 /58 Sept.1-3  Dry M a t t e r I  £0 --  /57  Layer  l  40 --  At  Layer  /58 /D9 J a n . Feb,  pared to a storage loss of 16.2 percent f o r the remaining 180  days. The largest part of the t o t a l loss from f i l l i n g to feed-  ing  took place i n the f i r s t month a f t e r f i l l i n g .  The  subse-  quent storage losses were much less important, although they amounted to over 40 percent of the y i e l d . In 1958-59 the t o t a l cost of a l l loss at $5.00 per ton pea vine delivered, no labour included, was to the o r i g i n a l cost of  $325.  $253»  compared  The cost of the t o t a l loss  per square foot of silage surface was 46.8 cents.  The  ini-  t i a l cost of the p l a s t i c sheet was 2 cents per square foot. The loss i n the "sub surface" layer alone was  approximately  6.1 cents per square foot of exposed surface f o r the storage period.  Storage losses were estimated at 12.3  cents  per square foot of exposed surface from September 3 to March 6th. The effect of a p l a s t i c cover over part of the mature grass silage i n the adjoining s i l o indicated much lower losses from the p l a s t i c protected area.  The calculated  " s p o i l " layer loss from the exposed sample was 6.7 percent of the t o t a l dry matter present.  The apparent effect of the  p l a s t i c was to reduce the surface loss almost to zero, and also to reduce the dry matter l o s t by fermentation, as reported f o r experimental metal s i l o s (7). The  combination  of higher density and higher dry matter content per pound of wet silage under the p l a s t i c sheet as compared to the adjacent area resulted i n a net .yield from an adjacent unprotected area.  The exposed silage contained approxi-  mately 85 percent of the net y i e l d of the protected area i n almost the same volume, made from the same material at the same time, under s i m i l a r conditions' of packing and sprinkling.  The p l a s t i c sheet was applied shortly a f t e r packing  and covered with sawdust to hold i t down and protect i t . The depth of silage i n a horizontal s i l o affects i t s storage e f f i c i e n c y considerably.  In general, the e f f i c i -  ency of storage increases as the depth increases, since both unit building cost and percent loss of silage decrease with increasing depth.  The net yields at shallow depths are very  low, and f o r most outdoor storage any f i n a l settled depth under four feet i s l i k e l y to be disappointing.  The B.C. De-  partment of Agriculture F i e l d Crops Branch i n a b u l l e t i n issued March 1958 recommend a minimum width of 16 feet and a minimum settled depth of 6 feet f o r horizontal s i l o s . Surface protection against r a i n f a l l by any means during the storage period would have to be done f o r a small cost, much less than would provide a roof, and amounting to less than $34.00 f o r a 36 foot by 15 foot silage surface  area.  A p l a s t i c sheet would more than pay f o r i t s e l f under such conditions, but no roof could be constructed and maintained for  t h i s cost.  The roof would prevent most of the "sub sur-  face" loss and the runoff l o s s , but would not a f f e c t the large losses i n the fermentation period, nor the development of the " s p o i l " layer. A p l a s t i c sheet to seal the surface of the silage can be j u s t i f i e d f o r lower Fraser Valley f a l l and winter exposure  -47conditions, on the basis of reduced storage losses alone. A considerably greater feeding y i e l d could be expected i f the p l a s t i c sheet was used to seal the silage surface immediatel y after packing was completed.  In practice, p l a s t i c sheets  used to seal horizontal s i l o s and stack s i l o s  immediately  after packing have resulted i n t o t a l dry matter losses which are negligible under English exposure conditions (4, 16). A further unmeasured value of both a roof and an impervious surface cover i s the maintenance of the o r i g i n a l percent dry matter with the associated higher dry matter i n take by animals s e l f feeding from the s i l a g e .  Hash consid-  ered that any silage with dry matter under twenty percent was low dry matter silage (18). CONCLUSIONS The t o t a l loss of dry matter i n pea vine silage i n an unprotected horizontal s i l o from f i l l i n g to feeding was very high.  The losses during the f i r s t month after f i l l i n g were  the most important, and any method of reducing the losses during  the fermentation period would be more important than pro-  tection during subsequent storage. with time and r a i n f a l l .  Storage losses increased  The major storage loss resulted from  the formation of an unpalatable "sub surface layer" under the " s p o i l layer", apparently from translocation of material from the " s p o i l layer" and some secondary fermentations.  The dev-  elopment of the "sub surface" layer was apparently related to l i q u i d movement through the " s p o i l layer" into the s i l a g e . A second important loss was the disappearance  of dry matter  -48from the s i l o during the storage period.  This l a t t e r loss was  greater than the calculated dry matter loss i n a l l the e f f l u ent l i q u i d s f o r the same period. The dry matter l o s t i n a l l effluent l i q u i d s during the s t orage period was only 4»5 percent of the input dry matter, but i t contained an estimated 9 percent of the protein and 18 percent of the ash.  The greatest part of the dry matter loss i n  the effluent l i q u i d s was i n the"runoff"liquids collected from the "toe" of the s i l o .  The dry matter l o s t i n l i q u i d pass-  ing down along the walls was small and the dry matter l i q u i d draining from the f l o o r of the s i l o was n e g l i g i b l e . The density of the silage increased with time but the dry matter per cubic foot and dry matter per pound of silage decreased during the storage period. The use of a p l a s t i c sheet to seal the top of the silage immediately after packing appears to be the best and most economical method of reducing the dry matter losses during storage. The cost of the p l a s t i c and handling costs are much less than the value of the silage conserved by the sheet during the storage period. A further advantage when the sheet i s used to seal the s i l o immediately a f t e r packing, are the lower fermentation loss and the maintenance of the dry matter content per pound of s i l a g e .  -49LITERATURE CITED 1.  A l l r e d , K.R. & Kennedy, W.K., "The Use of Small S i l o s to Determine Dry Matter Loss During E n s i l i n g . " Agronomy Journal, Y o l . 48, Pages 308-313, July, 1956.  2.  Archibald, J.G. & Gunness, C.I., "Seepage Losses Prom a S i l o . " Journal of Dairy Science, Y o l . 28, Pages 321-324, A p r i l 1945.  3.  Barnett, A.J.G., "Silage Fermentation." Butterworths S c i e n t i f i c Publications, London 1954. Drainage, Pages 57-62.  4.  Beaucourt, D.F., " P l a s t i c S i l o s , A Mew Way to Make Silage From Grass Crops."  Implement and Tractor Trade  Journal, 1957 (Abstract). 5.  B l i s h , M.J., "Factors Affecting Quality and Composition of Sunflower Silage."  Montana A g r i c u l t u r a l  Experimental Station B u l l e t i n Ho. 74, 1921. 6.  Bobsledt, G., "Hutrient Yalues of Hay and Silage As Affected By Harvesting, Processing and Storage." A g r i c u l t u r a l Engineering (Journal of American Society of A g r i c u l t u r a l Engineers) Y o l . 25, Pages 337-340, Sept. - Oct. 1944.  7. Cooper, D.J., Gordukes, W.E. & K a l b f l e i s c h , W., "A Test S i l o and Apparatus For E n s i l i n g Studies." Canadian Journal of Plant Science V o l . 38, Pages 181-183, A p r i l 1958. 8. Esmay, M.Li , Brooker, D.B. & McKibben, J.S., "Lateral Pressures on Horizontal S i l o s . "  Agricultural  Engineering (Journal of American Society of A g r i c u l t u r a l Engineers) October 1955, V o l . 36, Pages 651-653. 9.  Le C l e r c , J.A., "Losses i n Making Hay and Silage." U.S. A g r i c u l t u r a l Yearbook 1939. Pages 992-1016.  10* "Making Good Silage i n Horizontal S i l o s . " A g r i c u l t u r a l Research Report V o l . 6 No. 8, Feb. 1958, Page IE U.S. Department of Agriculture, Washington, D.C. 11.  Monroe, C.F. & Others. "Losses of Nutrient i n Hay and Meadow Crop Silage During Storage."  Journal of Dairy Science,  V o l . 29, Pages 239-256. Bibliography Pages 252-256, A p r i l 1946. 12.  Moore, H.I., " S i l o s and Silage." Farmer and Stockbreeder Publications, London 1950.  13.  O t i s , C.K. & L i e u , R.C., "Here's Where You Are Getting Silage Losses."  Minnesota A g r i c u l t u r a l Experimental  Farm and Home Service. V o l . 13, Pages 12-13, 1955.  -5114.  Otis, O.K.  & Pomroy, J.H., "Density, a Tool i n S i l o  Research." A g r i c u l t u r a l Engineering (Journal of American Society of A g r i c u l t u r a l Engineers)  Mov-  Dec. 1957, Y o l . 38, Mo.. 11-12, Page 806. 15.  Perkins, A.E., "Losses i n Silage Making." Ohio A g r i c u l t u r a l Experimental Bimonthly B u l l e t i n . Y o l . 220, Pages 32-34. Jan. 1943.  16.  "Silage With a P l a s t i c Skin", Power Farming i n A u s t r a l i a and Mew  17.  Zealand, 1957  S i l l , J.T. & Sears, R.,  "Roofing a S i l o to Reduce Stor-  age Losses." Mew  Zealand Journal of Science  and Technology. A p r i l 18.  (Abstract).  1942.  Waterson, H.A. & Mash, M.J., "Silage Making i n Scotland" Scottish Agriculture, Y o l . 36, Mo. 1, Summer 1956.  19.  Watson, S.J., "The Science and Practice of Conservation Grass and Forage Crops." The F e r t i l i z e r and Feeding Stuffs Journal, London 1939. Y o l . 1 and 2.  20.  Watson, S.J. & Ferguson, W.S.., "Losses i n Dry Matter and Digestive Mutrients i n Low Temperature Silage With and Without Molasses and Mineral Acids." Journal A g r i c u l t u r a l Science, Y o l . 27, Page 270107, Jan. 1937.  APPENDIX  TABLE A RAIMFALL 1957-1958 Month & Date  Precipitat ion  Aug./57 22 .20 .09 23 Month t o t a l Cumulative  .29 .29  Sept./57 1 5 6 17 26 Month t o t a l Cumulative  1.16 1.45  .04 .80 .17 .04 .11  Gct./57 .01 7 12 .73 .04 13 .40 22 23 1.02 .20 24 .20 25 .20 28 .44 29 Month t o t a l Cumulative Hov./57 9 10 11 12 13 14 15 17 18 21 22 23 25 27 29 30 Month t o t a l Cumulative  .05 .44 .91 .33 .59 .11 .12 .24 .01 .05 .04 .05 .12 .33 .09 .29  3.24 4.69  3.67 8.36  Month & Date Dec./57 1 2 3 4 5 6 7 10 11 13 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 Month t o t a l Cumulative  Precipi tation .17 .16 .02 .25 .52 .05 .04 .05 .09 .37 .33 .20 .28 .38 .08 .26 .09 .11 .48 .31 .50 .60 1.12 .11 .15  -54TABLE A (cont'd) RAINFALL 1957-1958 Month & Date Jan./58 1 2 3 7 8 9 10 11 13 14 15 16 20 21 22 23 24 25 26 27 28 29 30 Month t o t a l Cumulative  Precipitation .05 .11 .17 1.01 .22 .63 .33 .47 .90 .86 .36 .63 .17 .27 2.07 1.87 .18 .06 .04 .27 .76 .22 .02  11.25 26.33  Month & Date Feb./58 3 5 6 7 8 9 12 14 15 16 17 18 20 21 22 23 24 25 Month t o t a l Cumulative Mar./58 4 6 7 8 Month t o t a l (to 15th) Cumulative  Precipitation. .14 .02 .25 .35 .40 .41 .23 .12 .54 .27 .57 .15 .08 .59 .17 .43 .45 .01 5.77 32.10 .04 .32 .06 .12 .54 32.64  TABLE B RAINFALL 1958-1959 Month & Date Aug./58 2 6 26 28 31 Month t o t a l Cumulative Sept./58 8 10 15 16 17 18 19 20 24 25 26 Month t o t a l Cumulative 0ct./58 6 7 8  9  10 11 12 14 17 18 30 31 Month t o t a l Cumulative  Precipitation .37 .23 .02 .94 .30  .04 .02 .59 .36 .03 .44 .07 .29 .27 .04 .01  .09 .15 .13 1.15 .28 1.18 .18 .07 .46 .17 .06 .34  Month & Date Nov./58 1 2  3 5  1.86 1.86  2.16 4.02  7  9  10 11 13 17 18 19 20 21 22 23 30 Month t o t a l Cumulative Dec/58 1 2  5  4.26 8.28  6 7 8 9 10 11 14 15 16 17 19 20 21 23  24  25 26 28 29 30 31 Month t o t a l Cumulative  Precipitation .10 .06 .61 .51 .40 .03 .53 .50 .01 .52 .68 .56 .09 .53 .06 .14 1.96  7.29 15.57  .53 .38 .26 .96 .13 .24 .38 .31 .17 .04 .09 .36  1.45  .28 .64 .03 .01 .38 .26 .21 .43 .48 .04 .05  8.11 23.68  -56TABLE B (cont'd) BAINPALL 1958-1959 Month & Date Jan./59 4 5 6 7 8 9 10 11 12 14 15 16 17 18 21 22 23 24 25 26 28 Month t o t a l Cumulative  Precipitation .25 .42 .25 .16 .08 .29 .04 .33 .05 .09 .90 .14 .13 .02 .68 1.63 .58 .26 .03 .44 .01  Month & Date Feh./59 1 2 3 4 5 6 12 13 16 19 22 23 24 25 26 27 28 Month t o t a l Cumulative  6.78 30.46  Precipitation^ .01 .02 .04 .20 .44 .20 .11 .33 .36 .18 .18 .43 2.01 .08 .05 .93 .07  5.74 36.20  -57IABLE C EFFLUENT PLOW PROM "FLOOR" AREA Percent Dry Matter  Date  1 9 5 7 - 1 9 5 8  July 31 Aug. 2 4 7  10  Sept.l 14 25 28 Oct. 14 26 Nov. 4  2.00 1.35 1.78 1.98 1.98 5.60  3.72  4.05  JZT .25  .25  .25 •50 .10 1.00  13  15 20 Dec. 2 9 21 Jan. 1 6 14 21 Feb. 3  Gallons  .50  Gallons Per Month  14.69 0.75 0.75  1.60  .75 1.35 .25  5.27  .25 Total  20.59  2.30  .50  -58TABLE D RUNOFF AND EFFLUENT LOSSES 1958 - 1959 Date  Effluent from Test Area  Aug. 1 .05 g a l . 3 5 6 .05 7 8 9 10 11 12 13 14 17 21 24 26 29 .10 L total .12 ,1 2 .05 1.00 8 1.00 15 16 .83 17 .83 18 1.00* 2.00* 19 20 1.00* 22 2.00* 17. 23 24 .5 25 26 28 2. 30 Month t o t a l 29.3  Effluent from "Wall" Area .75 g a l . .65  1.40  Effluent from Guard & "Runoff 10.0* g a l . 3.7 12.0* 14.6* 2.5 (plugging) 22.5 10.0 23.0 20.0* 3.5 7.1 1.5 3.5 4.0 8.0* 4.5 8.2* 154.6 10.0  .70  1. .5 .5 1.0 .5 3.2  39.8(airlocked) 0.7 24. 32. 17. 19. 29. 34. 2. 8.. 7. 3.5  l?-5  237.5  * some losses Volumes recorded are t o t a l accumulation since previous readings.  -59TABLE D (cont'd) RUNOFF AID EFFLUENT LOSSES 1958 - 1959 Effluent from Test Area  Date Oct. 7 8 9 10 11  .  13  2.0 2.0 .5  Effluent from "Wall" Area  Effluent from Guarda*Runoff* 3.5 22.0* 30. 40. 40.  .5  1.0* 45.0* ( l i n leaned)40.* 45* 15. 8. 27. 2.6 30. 1. 2.5 17. 12. 9. 6. 2. 5. 16. 299.10 121.0 :  14 15 16 17 19 21 22 24 26 28 30 Month t o t a l 43" 6, Nov. 1 18. 2 10. 3 4 25 5 18. 7 .25 21. 9 17. 10 2.5 .125 15. 11 13. 25. .06 12 7.1 5.2 14 2.0 .06 5.0 .75 16 .125 25. 17 15.5 .06 10. 18 .06 9.2 55. 19 2.6 .125 55.* 20 5.2 .06 58. 22 28. 23 25. 24 40. 25 14. 26 12.5 27 9. 29 .06 2.5 30 ?4 * Month t o t a l 7985 gal. 57.85 gal, 533.2 g a l . * some losses Volumes recorded are t o t a l accumulation since previous readings.  -60TABLE D (cont'd) EUNOFF AND EFFLUENT LOSSES 1958 - 1959 Effluent from Test Area  Date  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 L total  Effluent from "Wall" Area  .06  1.  .06 .06 .12 .06  1.  .06  .06  .06  .06 .12 .06 .06 .84  2.5 1. 1.  1.  1.  1. 1.5 1. 12.0  Volumes recorded are t o t a l accumulation since previous readings.  Effluent from Guard&Eunoff 80. 32. 32. 21. 26. 30. 50. 32. 18. 21. 18. 12. 14. 11. 6. 6. 64. 61. 35. 46. 35. 28. 31. 16. 31. 26. 21. 28. 41. 35. 26. 933.  -61TABLB D (cont*d) RUNOFF AND EFFLUENT LOSSES 1958 - 1959 Date  Jan. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Month t o t a l  Effluent from Test Area  Effluent from "Wall" Area  .06  1. 1.5  .06  2.5  .06 .20  16 11 7 7 26 35 35 26 35 21 35 5.6  1. 2. 2.5  3.5 .12 .06  1.5  lost  1. 1.  .06  3.5 1. 10.5  .62 g a l .  Effluent from Guard&" Runoff"  32.5 gal..  * some losses Volumes recorded are t o t a l accumulation since previous readings.  20 19 25* 35 26 21 35* 38 35* 75 35* 40 34 43 8  748.6 g a l .  -62TABLE B (cont'd) RUNOFF AID EFFLUENT LOSSES ' 1958 - 1959 Date  Effluent from Test Area  Effluent from Wall Area  Feb. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28  .06  .06  .06  20. 2.4 1.5 1.  Month t o t a l  .42 gal.  73.2 gal,  Mar. 1 2 Month t o t a l  .06  2.6 6.0 8.6 g a l .  2.3 5.0  10. 10. 3.2 1.0 23. 13. 9. 32.. 19.  2.5  7.  1.2 1.2 1.2  .06 .06  .06  2.5 2.6 2.6 11.0 10. 1.0 3.1 2.1  .06  706  Effluent from Guards"Runoff"  * some losses Volumes recorded are t o t a l accumulation since previous readings.  37. 15. 2.5 4.. 12. * 14. 5.6 9. 2.6 10. 45., 58. 35. 19. 9. 404.9 g a l . 37. 21  707gal.  -63xABLB E PIEZOMETER PERFORMANCE 1958 - 1959 November 29 Three piezometers i n s t a l l e d near "toe" of s i l o at 12 inches, 24 inches, and f l o o r l e v e l . Tested to ground when immersed i n effluent i n dam approximately equal to 2.3 amps.(high scale) December 1 3 4 7 January  24 inch c e l l read 0.2 i n d i c a t i n g i n s u l a t i o n failure 12 inch c e l l read 0.6 - surface water leak 24 inch, 12 inch c e l l s , both read 0.2 - i n s u l ation f a i l u r e A l l wires missing.  31 New piezometers i n s t a l l e d i n test area and near "toe" of silage at 12 inches, 24 inches and floor level. Ground put i n s i l o h a l f way between piezometers. Wet reading approximately equal to 2.0  February 0-4Nothing 5  24 inch test area c e l l flooded - surface leakage repacked hole  17 12 inch "toe" c e l l 0.2 - been wet or "leaking" 21 12 inch "toe" c e l l reading down to approximately 0.05 23 Floor c e l l , "toe" - 0.9 - flooded by backed up pool behind dam. 25 Floor c e l l i n test area 0.05 - "leaking" Floor c e l l , "toe" area 0 reading.  -64-  APPENDIX F PERMEABILITY EQUATION Tne  h y d r a u l i c concept  of water movement i n a mass uses the  p r i n c i p l e of flow as a r e s u l t of d i f f e r e n c e s i n water p r e s s u r e at d i f f e r e n t  p o i n t s i n the mass.  The  d e s c r i b e d by the g e n e r a l equation Q, of l i q u i d f l o w i n g through  a  flow of l i q u i d can  be  AV where Q, i s the volume  a plane s u r f a c e i n the mass i n a  g i v e n time; A i s the conducting a r e a and V i s the average v e l o c i t y o f flow through  the conducting a r e a .  In a s o i l or s i m i -  l a r mass, n e i t h e r the conducting area nor the average can be e a s i l y  velocity  computed.  T h e r e f o r e , the g e n e r a l flow equation i s m o d i f i e d to Q=AKi. The  t o t a l a r e a of the sample p e r p e n d i c u l a r to the d i r e c t i o n  flow i s taken as A.  of  The h y d r a u l i c g r a d i e n t i i s taken as the  head h d i v i d e d by the l e n g t h of t r a v e l , L , through Then the constant K can be determined h, L , and A can be measured.  the  sample.  e x p e r i m e n t a l l y s i n c e Q,  

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