Persistent Link:
http://hdl.handle.net/10150/203773
Title:
Water Use Efficiency of Forage Sorghum Grown with Sub-optimal Irrigation, 2009
Author:
Ottman, Michael J.
Issue Date:
Sep-2010
Publisher:
College of Agriculture, University of Arizona (Tucson, AZ)
Journal:
Forage and Grain: A College of Agriculture and Life Sciences Report
Abstract:
A forage sorghum irrigation study was conducted at Maricopa, AZ to determine water use and if sub-optimal irrigation increases water use efficiency and profitability. Sorghum was planted on July 10 with a row spacing of 40 inches and irrigated three times with a total of 8.7 inches of water to establish the crop. Variable amounts of irrigation water were applied commencing on Aug 12 based on 25, 50, 75, and 100% of estimated crop water use (evapotranspiration, ET). The plots were 53.3 ft wide (16 rows) and 40 ft long. ET was estimated from soil water measurements using a neutron probe. The total amount of water applied was 15.5, 19.8, 23.7, and 27.8 inches for the 25, 50, 75, and 100% ET treatments, respectively. The forage was harvested on Oct 28 near the soft dough stage. Forage yields adjusted to 70% moisture were 11.3, 16.4, 21.5, and 23.1 tons/acre for the 25, 50, 75, and 100% ET treatments, respectively. Yield produced per inch of water used by the crop (WUEET, water use efficiency of water used in ET) increased with water application. Yield produced per inch of water applied to the crop (WUEirr, water use efficiency of irrigation water applied plus rainfall) also increased with water application, but then decreased from the 75 to 100% ET treatments. Nevertheless, sub-optimal irrigation strategies are not economical using the results from this study assuming a water cost of $45 per acre-foot and a sorghum silage value of $20 per ton. For sub-optimal irrigation strategies to be economical, water costs would have to increase, sorghum silage value would have to decrease, or the differences in the irrigation efficiencies of the strategies being compared would have to be greater than measured in the present study.
Keywords:
Agriculture -- Arizona; Grain -- Arizona; Forage plants -- Arizona; Sorghum -- Arizona; Sorghum -- Irrigation
Series/Report no.:
AZ1526; Series P-160

Full metadata record

DC FieldValue Language
dc.titleWater Use Efficiency of Forage Sorghum Grown with Sub-optimal Irrigation, 2009en_US
dc.contributor.authorOttman, Michael J.en_US
dc.date.issued2010-09-
dc.publisherCollege of Agriculture, University of Arizona (Tucson, AZ)en_US
dc.identifier.journalForage and Grain: A College of Agriculture and Life Sciences Reporten_US
dc.description.abstractA forage sorghum irrigation study was conducted at Maricopa, AZ to determine water use and if sub-optimal irrigation increases water use efficiency and profitability. Sorghum was planted on July 10 with a row spacing of 40 inches and irrigated three times with a total of 8.7 inches of water to establish the crop. Variable amounts of irrigation water were applied commencing on Aug 12 based on 25, 50, 75, and 100% of estimated crop water use (evapotranspiration, ET). The plots were 53.3 ft wide (16 rows) and 40 ft long. ET was estimated from soil water measurements using a neutron probe. The total amount of water applied was 15.5, 19.8, 23.7, and 27.8 inches for the 25, 50, 75, and 100% ET treatments, respectively. The forage was harvested on Oct 28 near the soft dough stage. Forage yields adjusted to 70% moisture were 11.3, 16.4, 21.5, and 23.1 tons/acre for the 25, 50, 75, and 100% ET treatments, respectively. Yield produced per inch of water used by the crop (WUEET, water use efficiency of water used in ET) increased with water application. Yield produced per inch of water applied to the crop (WUEirr, water use efficiency of irrigation water applied plus rainfall) also increased with water application, but then decreased from the 75 to 100% ET treatments. Nevertheless, sub-optimal irrigation strategies are not economical using the results from this study assuming a water cost of $45 per acre-foot and a sorghum silage value of $20 per ton. For sub-optimal irrigation strategies to be economical, water costs would have to increase, sorghum silage value would have to decrease, or the differences in the irrigation efficiencies of the strategies being compared would have to be greater than measured in the present study.en_US
dc.subjectAgriculture -- Arizonaen_US
dc.subjectGrain -- Arizonaen_US
dc.subjectForage plants -- Arizonaen_US
dc.subjectSorghum -- Arizonaen_US
dc.subjectSorghum -- Irrigationen_US
dc.identifier.urihttp://hdl.handle.net/10150/203773-
dc.relation.ispartofseriesAZ1526en_US
dc.relation.ispartofseriesSeries P-160en_US
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