Crop water use requirements and water use efficiency

Presented at the 15th annual Central Plains irrigation conference and exposition proceedings on February 4-5, 2003 at the City Limits Convention Center in Colby, Kansas.Includes bibliographical references

MF2471

Daniel M. O'Brien, et al, The economics of converting from surface to sprinkler irrigation for various pumping capacities, Kansas State University, November 2000

Corn and grain sorghum response to limited irrigation, drought, and hail

A field study was conducted for eight years in southwest Kansas near Garden City to measure the response of corn and grain sorghum to limited irrigation in the region. An irrigation variable was imposed on each crop, with six irrigation treatments from full irrigation scheduled to minimize soil water deficits to minimal or no irrigation. To create differences in the amount of irrigation across treatments, the time between 25-mm irrigation events increased as irrigation decreased. A historic drought occurred during 2011 and 2012 when cropping season precipitation, the precipitation occurring from the harvest of the prior crop through the harvest of the next crop, was 60% of the 30-year average. Except for 2008, average cropping season precipitation was 8% above average during the prior six years. Linear regressions of corn and sorghum grain yields (GY) and dry matter yields (DMY) versus crop evapotranspiration (ETc) from all years combined, except hail damaged sorghum in 2005, produced R2 values from 0.71 to 0.79. One hailstorm during 2005 damaged sorghum to the extent that yields did not vary with respect to ETc or irrigation. Hail events in 2005 and 2006 occurred at nearly the same growth stage for corn caused lower leaf area and yields than during other wet years with no hail. Using quadratic regressions, corn yields during wet years with no hail, wet years with hail, and dry years had distinctly different dependence on irrigation. Although sorghum yields during wet years tended to increase as irrigation increased, sorghum’s response to irrigation was less than for corn during the same years. During dry years, sorghum and corn were highly dependent on irrigation. Net economic returns (NR) of continuous corn, continuous sorghum, cornsorghum, corn-wheat, and sorghum-wheat rotations were each higher with a year receiving average precipitation (460 mm) than a year receiving 60% of average precipitation (280 mm). The NR of continuous corn dominated the rest of the rotations when irrigation was more than 230 to 330 mm in the dry year and 90 to 180 mm in wet year. As farmers choose crop rotations, they need to consider management factors and crop tolerance to soil water stress in addition to potential NR

Using livestock wastewater with SDI: a status report after three seasons

Presented at the Central Plains irrigation short course and exposition on February 5-6, 2001 at the Holiday Inn in Kearney, Nebraska.Using subsurface drip irrigation (SDI) with lagoon wastewater has many potential advantages. The challenge is to design and manage the SDI system to prevent emitter clogging. A study was initiated in 1998 to test the performance of five types of driplines (with emitter flow rates of 0.15, 0.24, 0.40, 0.60, and 0.92 gal/hr-emitter) with lagoon wastewater. A disk filter (200 mesh, with openings of 0.003 inches) was used and shock treatments of chlorine and acid were injected periodically. Over the course of three seasons (1998-2000) a total of approximately 52 inches of irrigation water has been applied through the SDI system. The flow rates of the two smallest emitter sizes, 0.15 gal/hr-emitter and 0.24 gal/hr-emitter have decreased approximately 30% during the three seasons, indicating some emitter clogging. The three largest driplines (0.40, 0.60, and 0.92 gal/hr-emitters) have had less than 5% reduction in flow rate. The disk filter and automatic backflush controller have performed adequately with the beef livestock wastewater in all three years. Based on these results, the use of SDI with beef lagoon wastewater shows promise. However, the smaller emitter sizes normally used with groundwater sources in western Kansas may be risky for use with lagoon wastewater and the long-term (> 3 growing seasons) effects are untested

Proceedings of the 24th annual Central Plains irrigation conference

Presented at Proceedings of the 24th annual Central Plains irrigation conference held on February 21-22 in Colby, Kansas.Includes bibliographical references