|Baumhardt, Roland - Louis|
|JONES, ORDIE - Retired ARS Employee|
|SCANLON, BRIDGET - University Of Texas|
|REEDY, ROBERT - University Of Texas|
Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/10/2016
Publication Date: 2/28/2017
Citation: Baumhardt, R.L., Schwartz, R.C., Jones, O.R., Scanlon, B.R., Reedy, R.C., Marek, G.W. 2017. Long-term conventional and no-tillage effects on field hydrology and yields of a dryland crop rotation. Soil Science Society of America Journal. 81(1)200-209.
Interpretive Summary: Dryland farming will be a more common land use as water for irrigation from the Ogallala Aquifer declines. However, a broad knowledge of field hydrology for contrasting tillage paradigms is needed to improve sustainable dryland cropping systems. ARS scientists from Bushland, Texas and scientists from University of Texas Bureau Economic Geology quantified tillage effects on soil water, runoff, and deep drainage in relation to the yield of wheat and sorghum grown in a 3-year rotation. The long-term (1983 to 2013) runoff and deep drainage from a clay loam soil were greater with NT than SM tillage. Less evaporation with NT increased stored soil water and summer crop yield over SM tillage. Results of the comprehensive field hydrology show dryland cropping systems depend on evaporation control to increase water for growth. These findings will help farmers and crop consultants optimize future cropping practices for sustained semiarid dryland production.
Technical Abstract: Semiarid dryland crop yields with no-till, NT, residue management are often greater than stubble-mulch, SM, tillage as a result of improved soil conditions and water conservation, but information on long-term tillage effects on field hydrology and sustained crop production are needed. Our objective was to quantify the effects of NT and SM on stored soil water, runoff, and deep drainage through a clay loam soil in relation to crop growth and yield. Wheat (Triticum aestivum L.) and grain sorghum [Sorghum bicolor (L.) Moench] were grown using the 3-year wheat-sorghum-fallow (WSF) rotation from 1983 to 2013. We measured crop growth and yield factors, precipitation, runoff, and chloride concentration to depths of 10 to 20 m. Improved infiltration with residue cover was not reflected in the observed NT runoff during fallow (57 mm) that was greater than runoff with SM tillage (33 mm). Annual deep drainage averaged 2mm for SM and 14 mm for NT dryland crop production based on chloride displacement compared with no drainage below the root zone of adjacent native rangeland. Despite greater runoff and drainage, available soil water for the 1.8 m profile at wheat and sorghum planting averaged 194 mm for NT compared with 166 mm for SM. Although wheat growth and grain yield did not vary with tillage, NT significantly (P less than 0.05) increased sorghum grain yield 17% to 3,420 kg per ha over the lower 2,920 kg per ha for SM tillage. We attributed the greater sorghum yield with NT to increased crop water use.