Location: Soil and Water Management ResearchTitle: Sunflower response to irrigation from limited water supplies with no-till management Author
Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/2013
Publication Date: 2/1/2012
Citation: Klocke, N.L., Currie, R.S., Tomsicek, D.J., Koehn, J.W. 2012. Sunflower response to irrigation from limited water supplies with no-till management. Transactions of the ASABE. 56(1):167-175. Interpretive Summary:
Technical Abstract: Limited irrigation necessitates maximizing economic returns by rotating crops, so we conducted a field study during 2005-2009 in southwest Kansas to determine the yield response of sunflower to irrigation and evapotranspiration (ETc) and to measure plant growth parameters and soil water use. Sunflowers were grown in a five-year rotation of corn-corn-wheat-sorghum-sunflower. Six irrigation treatments were imposed by applying 25 mm of irrigation every 4 to 18 days. When sunflowers were planted, sorghum stubble covered 59% to 53% of the surface as irrigation decreased. Similarly, sunflower residue covered 46% to 40% of the surface after planting the following corn crop. The rate at which sunflowers reached growth stages was not affected by irrigation amount. Seed yield (SY) averaged over five years did not differ significantly among the irrigation treatments; however, oil content increased significantly as irrigation decreased. Average annual crop evapotranspiration (ETc) decreased significantly from 481 to 414 mm as irrigation decreased. Because measured ETc for the driest treatment was 86% of fully irrigated ETc, a linear regression of SY data with respect to ETc was not realistic until a threshold value of ETc (ETc required to produce the first increment of seed) from prior field research was added to the dataset. Sunflower SY did not increase with added irrigation, which did not follow the normal pattern of diminishing yield returns as irrigation increases. Sunflowers, traditionally a dryland crop in the region, were able to utilize stored soil water at greater depths than other crops, which contributed to ETc and compensated for decreased irrigation. The soil stored more dormant season precipitation in the lowest irrigation treatment compared with the highest irrigation treatment (116 to 69 mm), and sunflowers receiving the least irrigation were able to use 63 mm more stored soil water during the following growing season. Small year-to-year variations in SY across irrigation treatments indicate that sunflowers can substitute for a crop that uses more water over the whole field or part of a field when water is very limited, which can reduce potential income risk from year to year.