|Evett, Steven - Steve|
Submitted to: ASA-CSSA-SSSA Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 7/4/2004
Publication Date: 10/5/2004
Citation: Ibragimov, N., Evett, S.R., Kamilov, B. 2004. Soil water balance of wheat and cotton in Uzbekistan by neutron probe [abstract]. Agronomy Abstracts, ASA-CSSA-SSSA Annual Meeting, Seattle, Washington. 2004 CDROM.
Technical Abstract: Investigations of water use and irrigation scheduling of irrigated winter wheat and of drip irrigated cotton were conducted in Uzbekistan on a deep silt loam soil in 2000, 2001, 2002, and 2003. Water use was established using the soil water balance approach on a weekly basis. Deep measurements of the soil profile water content were accomplished using soil moisture neutron probes. Water use was measured by the soil water balance method. Soil water measurements were compared with percentages of field capacity to determine irrigation rates and times during the growing season. The results revealed that drip irrigation of cotton under the given circumstances improved water use efficiency and seed-cotton yield. Under drip irrigation, the optimal mode of cotton irrigation scheduling was to irrigate at 70%,70%,and 70% of field capacity during each of the three major growth stages, respectively. This mode saved 35.3% of the irrigation water in comparison with surface irrigated cotton grown under the same condition. Seed-cotton yield was increased by 17.4% relative to the surface irrigated cotton. Optimal development and high crop productivity of winter wheat was reached when irrigation were scheduled at soil moisture levels of 75% of field capacity. More irrigation did not result in additional yield from the crop.