Large-scale on-farm implementation of soil moisture-based irrigation management strategies for increasing maize water productivity

摘要: Irrigated maize is produced on about 3.5 Mha in the U.S. Great Plains and western Corn Belt. Most irrigation water comes from groundwater. Persistent drought increased competition for resources threaten long-term viability of groundwater resources, which motivated our research to develop strategies increase productivity without noticeable reduction yield. Results previous at University Nebraska-Lincoln (UNL) experiment stations 2005 2006 found that it was possible substantially reduce amounts use efficiency (IWUE) crop (CWUE) (or productivity) with little or no yield using an regime applies less during growth stages are sensitive stress. Our hypothesis a soil moisture-based management approach fields would give similar results large production-scale, center-pivot irrigated Nebraska. To test this hypothesis, IWUE, CWUE, grain yields were compared extensive on-farm located eight locations over two years (16 site-years), representing more than 600 ha area. In each site-year, contiguous topography, properties, practices received different regimes: one managed by UNL researchers, other farmer site. Irrigation farmer-managed relied farmers’ traditional visual observations personal expertise, whereas timing UNL-managed based pre-determined depletion thresholds measured moisture sensors, as well phenology predicted simulation model combination real-time (in-season) historical weather data. The resulted greater depletion, decreased requirements enabled timely both (34% 32% application 2007 2008, respectively). average actual evapotranspiration (ETC) UNL- all sites 487 504 mm, respectively. field had seasonal ETC 511 548 Thus, when considered, 3% 7% respectively, although percentage much higher some fields. years, differences between not statistically significant (p = 0.75). On-farm implementation 38% 30% IWUE On average, CWUE value 4% those years. Reduction withdrawal $32.00 $74.10 ha-1 $44.46 $66.50 2008 energy saving additional net return farm income. study can have positive implications future systems regions practices.