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ARS Home » Plains Area » Bushland, Texas » Conservation and Production Research Laboratory » Soil and Water Management Research » Research » Publications at this Location » Publication #307777
Title: Replacing fallow with continuous cropping reduces crop water productivity of semiarid wheat

Author
item AIKEN, R - Kansas State University
item O'BRIEN, D - Kansas State University
item OLSON, B - Kansas State University
item MURRAY, L - Kansas State University

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/7/2012
Publication Date: 1/1/2013
Citation: Aiken, R.M., O'Brien, D.M., Olson, B.L., Murray, L. 2013. Replacing fallow with continuous cropping reduces crop water productivity of semiarid wheat. Agronomy Journal. 105(1):199-207.

Interpretive Summary:

Technical Abstract: Water supply frequently limits crop yield in semiarid cropping systems; water deficits can restrict yields in drought-affected subhumid regions. In semiarid wheat (Triticum aestivumL.)-based cropping systems, replacing an uncropped fallow period with a crop can increase precipitation use efficiency but reduce wheat productivity. Our objective was to analyze crop sequence and environmental effects on water use, components of water productivity, and net returns of winter wheat in a semiarid region. A field study was established to evaluate eight 3-year crop sequences, including a wheat phase followed by a feed grain phase (corn [Zea mays L.] or grain sorghum [Sorghum bicolor (L.) Moench]) and an oilseed phase (OS; spring canola [Brassica napus L.], soybean [Glycine max (L.) Merr.], sunflower [Helianthus annuus L.], or none [fallow]). Standard measurements included crop water use, canopy leaf area index at anthesis, biomass, grain yield, and yield components. Net return was calculated as the difference between crop revenue and total operating costs. Replacing an uncropped fallow period with an oil seed crop reduced water productivity responses of winter wheat (biomass, grain yield, and net returns) by 18, 31, and 56%, respectively, relative to that of winter wheat grown after fallow. These responses to continuous cropping corresponded to reductions in all components of a water-limiting yield production function. The modest water productivity observed (0.28 to 0.62 kg per cubic meter), relative to a reported global range of 0.6 to 1.7 kg per cubic meter, indicates opportunity to improve wheat water productivity through management and genetic gain.