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ARS Home » Plains Area » Fort Collins, Colorado » Center for Agricultural Resources Research » Water Management and Systems Research » Research » Publications at this Location » Publication #297469

Title: Quantifying crop water stress factors from soil water measurements in a limited irrigation experiment

item ANAPALLI, SASEENDRAN - Colorado State University
item Trout, Thomas
item Ahuja, Lajpat
item Ma, Liwang
item McMaster, Gregory
item ANDALES, ALLAN - Colorado State University
item CHAVEZ, JOSE - Colorado State University
item HAM, JAY - Colorado State University

Submitted to: Agricultural Systems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/24/2014
Publication Date: 12/14/2014
Citation: Anapalli, S.S., Trout, T.J., Ahuja, L.R., Ma, L., Mcmaster, G.S., Andales, A.A., Chavez, J.L., Ham, J. 2014. Quantifying crop water stress factors from soil water measurements in a limited irrigation experiment. Agricultural Systems. doi: org/10.1016/j.agsy.2014.11.005.

Interpretive Summary: With competing demands for fresh water from various sectors of the burgeoning human enterprises, increasing productivity of the water allocated for irrigation is required for sustained food security on the earth. There is a need and possibility for making agriculture water use less wasteful and more efficient through enhancing and applying the existing irrigation science and technologies. Considerable research is being conducted to see if we can enhance water use efficiency through the implementation of ‘limited irrigation’ water management practices for various crops in the Great Plains of the USA.Like other agro-management practices, the transfer of the developed location-specific short-term limited irrigation technologies across locations has been difficult due to varying precipitation regimes, soils and landscapes. Simulation models can synthesize and integrate data collected from available limited-term field studies, and present a way to extrapolate results to long-term weather conditions and to other soils and climates. However, adequacy of agricultural system models for this application, especially in limited irrigation water management, depends upon accurately simulating the imposed soil water stress effects on crop growth and yield. In this study, soil water measurements that span the whole growing season under corn grown under six irrigation treatments designed to meet 100 to 40% of ETc requirements during the growing season were analyzed for developing water stress factors that explain crop growth responses to the applied water. Potential water stress factor for simulations of corn using the Root Zone Water Quality Model of USDA-ARS was identified as: the ratio of Plant Available Water to its maximum in the root zone and its potential plant evapotranspiration demand.

Technical Abstract: Quantifying crop water stress factors from soil water measurements in a limited irrigation experiment. A correct simulation of crop responses to water stress is essential for a system model. In this study, we investigated three methods of quantifying water deficit stresses based on soil water measurements and their effects on simulating grain yield, biomass and foliage cover of corn (Zea Mays L). Experimental data were collected for six irrigation treatments designed to replace 40 to 100% of potential crop evapotranspiration (ETc) losses during the growing season, from 2008 to 2011 near Greeley, Colorado in a sandy loam soil (Limited Irrigation Research Farm, LIRF). Water available for plant uptake (PAW, plant available water) and the maximum PAW (MAW) in the soil were calculated for a constant 1 m soil profile from 45 days after planting till maturity. Water deficit stress factors were calculated as ratios of (1) PAW to alfalfa reference crop evapotranspiration (ETr ) (WSF1), (2) PAW to MAW (WSF2), and (3) WSF2 to ETr (WSF3). Average WSF1, WSF2 and WSF3 over the growing season were related to end of the season grain yield, biomass, and fraction foliage cover measurements. These stress factors were implemented in the RZWQM2 cropping system model and the calibrated results compared with those obtained from using current stress factors in CERES-maize module in RZWQM2. The best simulation of the measured grain yields, biomass and LAI was obtained using WSF3. The modified model was also tested for simulating dryland and limited irrigation studies at Akron, CO, and irrigated corn in a sandy loam soil at Zaragoza, Spain and in a sandy soil at Gainesville, Florida, USA. In general, WSF3 gave more accurate simulations of grain yields, biomass and LAI than WSF2, WSF1 and the original stress factor.