Submitted to: Intl Conference on Sustainable Agriculture for Food, Energy and Industry
Publication Type: Abstract Only
Publication Acceptance Date: June 30, 2005
Publication Date: December 1, 2005
Citation: Sainju, U.M., Lenssen, A.W., Evans, R.G., Caesar, T., Waddell, J.T. 2005. Tillage, crop rotations, and cultural practices effects on dryland soil and crop residue carbon and nitrogen. In: Proceedings of the International Conference on Sustainable Agriculture for Food, Energy and Industry, August, 22-27, 2005, St. Catharines, Canada. Available online at http://www.icsagr-fei.org/conference/2005/stcath/papers/a-sainj.doc Technical Abstract: Sustainable soil and crop management practices are needed to conserve soil C and N and to improve dryland soil quality and productivity in Northern Great Plains. The effects of two tillage [conventional till (CT) and no-till (NT)], four crop rotations [continuous spring wheat (CW), spring wheat-pea (W-P), spring wheat-barley-pea (W-B-P), and spring wheat-barley-corn-pea (W-B-C-P)], and two cultural practices [conventional (as practiced by local producers) and ecological (higher seed rates, delayed planting, wider spacing, different fertilizer placement, and straw management than in conventional practices)] were examined on dryland soil and crop residue C and N in eastern Montana in 2004. Crop residue cover, amount, and C and N contents were not influenced by tillage and cultural practices but residue cover and C content were higher in CW than in W-B-P and W-B-C-P. Soil NH4-N content at 0- to 5-cm depth was greater in ecological than in conventional practice, regardless of tillage and crop rotation, but at 5- to 20-cm it was greater in conventional than in ecological practice in NT. Soil NO3-N content at 0- to 5- and 0- to 20-cm was greater in ecological than in conventional practice in CT. Soil total N at 5- to 20- and 0- to 20-cm cm was greater in W-P than in CW in CT. Similarly, soil organic C at 5- to 20- and 0- to 20-cm was greater in conventional than in ecological practice. Crop residue and soil C and N contents varied between tillage, crop rotations, and cultural practices, probably due to quality, quantity, and rate of decomposition of crop residues in the soil.