TY - JOUR
T1 - High-yield irrigated maize in the Western U.S. Corn Belt
T2 - II. Irrigation management and crop water productivity
AU - Grassini, Patricio
AU - Yang, Haishun
AU - Irmak, Suat
AU - Thorburn, John
AU - Burr, Charles
AU - Cassman, Kenneth G.
N1 - Funding Information:
We are grateful to the Tri-Basin NRD board and staff, especially to Tammy Fahrenbruch for providing access to the crop and water use reports and helping with the survey and the many farmers who collaborated in this study. We also thank Drs Albert Weiss, James Specht, and Shashi Verma for useful comments on an earlier version of the paper. Support for this project comes from the Water, Energy and Agriculture Initiative, made possible with funding from the Nebraska Corn Board, the Nebraska Soybean Board, the Agricultural Research Division (ARD) at the University of Nebraska-Lincoln (UNL) and Nebraska Public Power District through the Nebraska Center for Energy Sciences Research at UNL . The senior author wishes also to acknowledge financial support from the Fulbright Program, UNL, and the ARD for his graduate assistantship.
PY - 2011/1/14
Y1 - 2011/1/14
N2 - Appropriate benchmarks for water productivity (WP), defined here as the amount of grain yield produced per unit of water supply, are needed to help identify and diagnose inefficiencies in crop production and water management in irrigated systems. Such analysis is lacking for maize in the Western U.S. Corn Belt where irrigated production represents 58% of total maize output. The objective of this paper was to quantify WP and identify opportunities to increase it in irrigated maize systems of central Nebraska. In the present study, a benchmark for maize WP was (i) developed from relationships between simulated yield and seasonal water supply (stored soil water and sowing-to-maturity rainfall plus irrigation) documented in a previous study; (ii) validated against actual data from crops grown with good management over a wide range of environments and water supply regimes (n=123); and (iii) used to evaluate WP of farmer's fields in central Nebraska using a 3-y database (2005-2007) that included field-specific values for yield and applied irrigation (n=777). The database was also used to quantify applied irrigation, irrigation water-use efficiency (IWUE; amount of yield produced per unit of applied irrigation), and the impact of agronomic practices on both parameters. Opportunities to improve irrigation management were evaluated using a maize simulation model in combination with actual weather records and detailed data on soil properties and crop management collected from a subset of fields (n=123). The linear function derived from the relationship between simulated grain yield and seasonal water supply, namely the mean WP function (slope=19.3kgha-1mm-1; x-intercept=100mm), proved to be a robust benchmark for maize WP when compared with actual yield and water supply data. Average farmer's WP in central Nebraska was ∼73% of the WP derived from the slope of the mean WP function. A substantial number of fields (55% of total) had water supply in excess of that required to achieve yield potential (900mm). Pivot irrigation (instead of surface irrigation) and conservation tillage in fields under soybean-maize rotation had the greatest IWUE and yield. Applied irrigation was 41 and 20% less under pivot and conservation tillage than under surface irrigation and conventional tillage, respectively. Simulation analysis showed that up to 32% of the annual water volume allocated to irrigated maize in the region could be saved with little yield penalty, by switching current surface systems to pivot, improving irrigation schedules to be more synchronous with crop water requirements and, as a fine-tune option, adopting limited irrigation.
AB - Appropriate benchmarks for water productivity (WP), defined here as the amount of grain yield produced per unit of water supply, are needed to help identify and diagnose inefficiencies in crop production and water management in irrigated systems. Such analysis is lacking for maize in the Western U.S. Corn Belt where irrigated production represents 58% of total maize output. The objective of this paper was to quantify WP and identify opportunities to increase it in irrigated maize systems of central Nebraska. In the present study, a benchmark for maize WP was (i) developed from relationships between simulated yield and seasonal water supply (stored soil water and sowing-to-maturity rainfall plus irrigation) documented in a previous study; (ii) validated against actual data from crops grown with good management over a wide range of environments and water supply regimes (n=123); and (iii) used to evaluate WP of farmer's fields in central Nebraska using a 3-y database (2005-2007) that included field-specific values for yield and applied irrigation (n=777). The database was also used to quantify applied irrigation, irrigation water-use efficiency (IWUE; amount of yield produced per unit of applied irrigation), and the impact of agronomic practices on both parameters. Opportunities to improve irrigation management were evaluated using a maize simulation model in combination with actual weather records and detailed data on soil properties and crop management collected from a subset of fields (n=123). The linear function derived from the relationship between simulated grain yield and seasonal water supply, namely the mean WP function (slope=19.3kgha-1mm-1; x-intercept=100mm), proved to be a robust benchmark for maize WP when compared with actual yield and water supply data. Average farmer's WP in central Nebraska was ∼73% of the WP derived from the slope of the mean WP function. A substantial number of fields (55% of total) had water supply in excess of that required to achieve yield potential (900mm). Pivot irrigation (instead of surface irrigation) and conservation tillage in fields under soybean-maize rotation had the greatest IWUE and yield. Applied irrigation was 41 and 20% less under pivot and conservation tillage than under surface irrigation and conventional tillage, respectively. Simulation analysis showed that up to 32% of the annual water volume allocated to irrigated maize in the region could be saved with little yield penalty, by switching current surface systems to pivot, improving irrigation schedules to be more synchronous with crop water requirements and, as a fine-tune option, adopting limited irrigation.
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U2 - 10.1016/j.fcr.2010.09.013
DO - 10.1016/j.fcr.2010.09.013
M3 - Article
AN - SCOPUS:78249272670
SN - 0378-4290
VL - 120
SP - 133
EP - 141
JO - Field Crops Research
JF - Field Crops Research
IS - 1
ER -