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United States Department of Agriculture

Agricultural Research Service

Title: Crop and Soil Response to Long-Term Tillage Practices in the Northern Great Plains

Authors
item Aase J Kristian,
item Pikul Jr, Joseph

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 14, 1994
Publication Date: N/A

Interpretive Summary: Summer fallow -- leaving the land idle for a season -- is common practice in the northern Great Plains; however, annual cropping may be economical. We evaluated feasibility of alternate agronomic management systems in lieu of fallow-crop rotation and effects on soil properties. The study began in 1983 on a sandy loam soil 7 miles north of Culbertson, Montana. Treatments were fallow-crop rotation, no-tillage annual cropping and various tillage practices with annual cropping. Spring wheat was main crop. Barley was included in one rotation. Phosphorous and nitrogen were adequate for crop growth in all 10 years; pH decreased about 0.06 units per year in the top 3 inch soil layer because of nitrogen fertilization. Soil bulk density differences in the surface layer appeared after 7 years. No-tillage annual crop had lowest density. Grain and straw yields with no-tillage were 80% of yields with fallow-crop. Total water-use efficiency was significantly greater with no-tillage than with fallow-crop. Soil organic carbon decreased nearly 0.4 g per kg of soil per year with fallow-crop. There was a negligible decline with no-tillage annual crop. No-tillage annual spring wheat production was the most efficient crop and soil management practice from the standpoint of yield, water-use efficiency, and beneficial soil properties.

Technical Abstract: Fallow-crop rotation is common in the northern Great Plains; with proper management annual cropping may be economical. Our objective was to determine viability of alternate agronomic management systems and soil response in lieu of conventional fallow-crop rotation. The study, begun 1983, was on a Dooley sandy loam 11 km north of Culbertson, Montana. Treatments were 1) fall sweep tillage, spring disk tillage, cropped year to spring wheat; 2) spring sweep tillage, cropped yearly to spring wheat 3) no-tillage, cropped yearly to spring wheat; 4) and 5) same as Treatment 1, except alternate year rotation of barley and spring wheat; 6) and 7) fallow-spring wheat rotation. Phosphorous and nitrogen were non- limiting in all years; pH decreased about 0.06 units per year in the 0-to-8 -cm layer because of nitrogen fertilization. Bulk density differences in 0-to 10-cm layer appeared after 7 years, with lowest density for the no- tillage annual crop treatment. Grain and straw yields with no-tillage were 80% of yields with fallow-crop. Total water-use efficiency was greater with no-tillage than with the fallow-crop. Soil organic carbon decreased nearly 0.4 g kg-1 per year with fallow-crop; there was a negligible decline with no-tillage annual crop. No-tillage annual spring wheat crop production was the most efficient crop and soil management practice from standpoint of yield, water use efficiency, and beneficial soil properties.

Last Modified: 7/31/2014
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