Biowaste usage for soil erosion control and soil physical improvement under potatoes (Solanum tuberosum) in Atlantic Canada

Abstract

Using potatoes (Solanum tuberosum L) as a test crop and standard erosion plots, a long-term study was done to assess the overall effects of straw mulch, compost (potato culls + manure + sawdust) and liquid pig manure (LPM) on soil physical properties, soil organic matter (SOM), erosion amounts and crop yield on a fine sandy loam in Prince Edward Island. The study occurred in two experimental phases separated by fallow periods. Phase 1 assessed treatment effects of straw mulch and compost during 1996-1999, and Phase 2 assessed treatment effects of LPM and compost during 2001-2002 and 2005-2006. Soil physical properties, mostly compaction-related, were penetration resistance, shear strength (TO), bulk density (BD), saturated hydraulic conductivity (HC), water content (SWC) and aggregate stability (AgSt), which, overall, were improved up to 27% with compost, the outstanding amendment. In Phase 1, compost significantly increased potato yield 9%. Runoff and sediment were, respectively, reduced with compost by 15 and 33%, and with mulching by 42 and 73%. Potato yield showed significant negative relations to soil compaction, whereby BD and TO, respectively, accounted for up to 89 and 70% of variation attributable to regression. In Phase 2, compost and LPM significantly increased yield by 23 to 38%. Compost alleviated soil compaction significantly, reducing BD by 14% and TO by 15 to 22%. It increased SOM almost 30%, AgSt almost 10%, SWC about 6% and HC more than twofold. Pig manure did not affect soil compaction for the most part or SOM, but increased AgSt and HC by 5 and 67%, respectively.Key words: Compost usage, straw mulching, liquid pig manure, soil organic matter, land degradation, soil erosion, soil conservation, soil improvement