Open Collections

Singfield, Corine

University of British Columbia

Cover crops are routinely used on farms to increase soil fertility, protect from erosion, and improve productivity. These green manure crops are predominantly managed with mechanical implements, which can cause adverse impacts on soil properties such as compaction, erosion, organic matter losses. The objective of this study was to investigate the viability of replacing tillage by using strip grazing pigs to manage cover crops (terminate and re-seed via trampling) and compare their impacts on cover crop growth and soil health to a system using typical tractor tillage. The experiment was conducted twice on two different areas of the same farm, one left fallow for 5 years, the other under previous organic market crop production. It was observed that cover crop coverage was 48% higher on average in the grazing system during the summer season and 35% more higher after a winter of growth. The proportion of weed cover varied according to the preceding land use; significantly more weeds were found in the tillage system where cropping activities had taken place before. Penetration resistance was significantly lower in the grazing system at the 15-30 cm depth which suggests it helped mitigate the plough pan layer. Mean aggregate stability was higher in the tillage system due to a higher fraction of macroaggregates even though there was a significantly higher fraction of microaggregates in the grazing system. Bulk density was not found to be significantly different between systems, but volumetric water content was significantly lower in the grazing plots. Nitrate levels were significantly higher in the grazing system, but grazing did not affect levels of ammonium, phosphorous, and permanganate oxidable carbon. Soil respiration was found to be significantly higher in the grazing system and mean earthworm count and weight were also 41% and 86% respectively. Overall, this study indicates that using grazing pigs to manage cover crops is a promising strategy that may help to prevent some of the negative impacts of tillage, even if used only over one growing season.  

Text

2024-01-10

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/87194

Soil Science

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/