Thursday, 5 January 2006 - 4:30 PM

Evaluation of late season irrigation strategies

Jeffrey C. Silvertooth, Russell Tronstad, and Abraham Galadima. University of Arizona, SWES Dept., Shantz 429, Bldg. #38, Tucson, AZ 85721-0038

A field experiment was conducted in 2004 and 2005at the University of Arizona Maricopa Agricultural Center (1,175ft. elevation) to evaluate the effects of five irrigation termination (IT1, IT2, IT3, IT4, and IT5) dates on yield and fiber micronaire of several Upland cotton varieties. In addition, the economic relationships of IT treatments were also evaluated. The first IT treatment (IT1) was made with the intention of terminating irrigations somewhat pre-maturely. Based upon current UA recommendations for IT to complete a single cycle fruit set, the more optimal date of IT would have included one or two additional irrigations (beyond IT1). In this experiment, IT2 was structured to provide an additional (one) irrigation before the more optimal date. For the IT3 plots, the intention was to attempt to time termination to match the conventional growers optimal date. The IT4 and IT5 were imposed to attempt to produce a second cycle fruit set and irrigations continued until 27 August and 21 September respectively. In general, lint yield and micronaire results revealed significant differences among the IT treatments. In a similar fashion to 2000-2002 IT experiments, micronaire and lint yield values consistently increased with later IT dates. The best micronaire and lint yield results were achieved with IT4 date, which received 12 in. less irrigation water than IT5. The 12 in. water saved equates to approximately 20% of the total water used under the conventional practice.

[ Recorded presentation ] Recorded presentation

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