Effects of burn/low-till on erosion and soil quality

摘要

Burn/low-till management of winter wheat (Triticum aestivum) is being practiced by some growers in the higher rainfall areas of the Pacific Northwestern Winter Wheat Region of the US. Residue burning eliminates the numerous seedbed tillage operations that are normally required to reduce residues and control weeds and diseases in continuous winter wheat production. The detrimental effects of burn and till systems on soil erosion are well documented. However, there is little or no data on the effects of burning with no-till or low-till annual cropping on either erosion or soil quality. A 3-year field study comparing winter season erosion resulting from burn/low-till (BLT) seeded winter wheat following winter wheat and conventionally managed (CM) winter wheat following various crops was completed in 1997. Results indicate soil loss from the BLT fields was not significantly different from that of the CM fields with various crops preceding winter wheat. For the BLT fields, soil loss was as closely related to soil disturbance (number of tillage operations) as to the amount of surface residue. When residue and crop cover did not differ with the number of tillage operations, an increased number of tillage operations after burning loosened the soil and resulted in greater soil loss. No adverse effects on soil loss or soil quality from using the BLT with one or two-pass seeding of winter wheat following winter wheat were found in this study. The results have implications for harvesting wheat stubble as a source of biomass, or as an alternative technique for initiating conversion from a conventional tillage to a no-till seeding system, without high initial investment in new seeding equipment.