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ARS Home » Pacific West Area » Pendleton, Oregon » Columbia Plateau Conservation Research Center » Research » Publications at this Location » Publication #250561
Title: One-pass tillage for summer fallow under arid summer conditions

Author
item Wuest, Stewart
item CORP, MARY - Oregon State University

Submitted to: Crop Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/10/2011
Publication Date: 12/23/2011
Citation: Wuest, S.B., Corp, M.K. 2011. One-pass tillage for summer fallow under arid summer conditions. Crop Management. DOI: 10.1094/CM-2011-1223-03-RS.

Interpretive Summary: Millions of hectares of cropland with as low as 6 inches annual precipitation are used for production of winter wheat in the Pacific Northwest, USA. Despite soil conservation advances, erosion continues to be a problem. This on-farm study analyzed soil water data under six farmer-implemented fallow tillage practices. Statistical tools were used to separate year-to-year weather effects from the performance of the treatments. Soil bulk density differences were adjusted for also. Except where weeds were a problem, tilled fallow produced 1% better seed-zone water compared to no-till at an average soil water content of about 8%. A low disturbance, wide-blade undercutter sweep treatment was similar or superior to the farmer’s more intensive conventional tillage system. We measured an increase of over 0.5% using a two-pass sweep–rodweed treatment compared to the conventional multiple-pass tillage. These results indicate that very low disturbance, low erosion tilled summerfallow systems are possible while maintaining or improving economic performance.

Technical Abstract: Millions of ha of cropland with as low as 150 mm (5.91 in) annual precipitation are used for production of winter wheat (Triticum aestivum L.) in the Pacific Northwest, USA. Despite soil conservation advances, erosion continues to be a problem. This on-farm study analyzed soil water data under six farmer-implemented fallow tillage practices. An incomplete block design in a mixed model was used to adjust treatment effects so that new treatments added in the third and fourth years of the four-year study could be compared to treatments present in all four years. Soil water content data was adjusted to depths of equivalent mass so that conclusions concerning water content would not be confounded with differences in soil bulk density. Except where weeds were a problem, tilled fallow produced 0.01 g g^1 (1%) better seed-zone water compared to no-till (at an average soil water content of about 0.08 g g^1 (8%)). A low disturbance, wide-blade undercutter sweep treatment was similar or superior to the farmer’s more intensive conventional tillage system. While not statistically significant, a measured increase of over 0.005 g g^1 (0.5%) using a two-pass sweep–rodweed treatment compared to the conventional multiple-pass tillage is incentive to further investigate and develop low disturbance systems.