title: [Optimal irrigation index for cotton drip irrigation under film mulching based on the evaporation from pan with constant water level].
abstract: A field experiment with two irrigation cycles and two irrigating water quotas at squaring stage and blossoming-boll forming stage was conducted in Urumqi of Xinjiang Autonomous Region, Northwest China in 2008-2009, aimed to explore the high-efficient irrigation index of cotton drip irrigation under film mulching. The effects of different water treatments on the seed yield, water consumption, and water use efficiency (WUE) of cotton were analyzed. In all treatments, there was a high correlation between the cotton water use and the evaporation from pan installed above the plant canopy. In high-yield cotton field (including the treatment T4 which had 10 days and 7 days of irrigation cycle with 30.0 mm and 37.5 mm of irrigating water quota at squaring stage and blossoming-boll forming stage, respectively in 2008, and the treatment T1 having 7 days of irrigation cycle with 22.5 mm and 37.5 mm of irrigating water quota at squaring stage and blossoming-boll forming stage, respectively in 2009), the pan-crop coefficient (Kp) at seedling stage, squaring stage, blossoming-boll forming stage, and boll opening stage was 0.29-0.30, 0.52-0.53, 0.74-0.88, and 0.19-0.20, respectively. As compared with the other treatments, T4 had the highest seed cotton yield (5060 kg x hm(-2)) and the highest WUE (1.00 kg x m(-3)) in 2008, whereas T1 had the highest seed cotton yield (4467 kg x hm(-2)) and the highest WUE (0.99 kg x m(-3)) in 2009. The averaged cumulative pan evaporation in 7 days and 10 days at squaring stage was 40-50 mm and 60-70 mm, respectively, and that in 7 days at blossoming-boll forming stage was 40-50 mm. It was suggested that in Xinjiang cotton area, irrigating 45 mm water for seedling emergence, no irrigation both at seedling stage and at boll opening stage, and irrigation was started when the pan evaporation reached 45-65 mm and 45 mm at squaring stage and blossoming-boll stage, respectively, the irrigating water quota could be determined by multiplying cumulative pan evaporation with Kp (the Ko was taken as 0.5, 0.75, 0.85, and 0.75 at squaring stage, early blossoming, full-blossoming, and late blossoming stage, respectively), which could be the high efficient irrigation index to obtain high yield and WUE in drip irrigation cotton field and to save irrigation water resources.
authors.affiliation: Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences/ Key Laboratory of Crop Water Use and Regulation, Ministry of Agriculture, Xinxiang 453002, Henan, China. shenxiaojun8003@163.com
authors.forename: Xiao-Jun
authors.initials: XJ
authors.lastname: Shen
authors.affiliation: Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences/ Key Laboratory of Crop Water Use and Regulation, Ministry of Agriculture, Xinxiang 453002, Henan, China.
authors.forename: Ji-Yang
authors.initials: JY
authors.lastname: Zhang
authors.affiliation: Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences/ Key Laboratory of Crop Water Use and Regulation, Ministry of Agriculture, Xinxiang 453002, Henan, China.
authors.forename: Jing-Sheng
authors.initials: JS
authors.lastname: Sun
authors.affiliation: Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences/ Key Laboratory of Crop Water Use and Regulation, Ministry of Agriculture, Xinxiang 453002, Henan, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Gao
authors.affiliation: College of Water Conservancy and Architectural Engineering, Shihezi University, Shihezi 832000, Xinjiang, China.
authors.forename: Ming-Si
authors.initials: MS
authors.lastname: Li
authors.affiliation: Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences/ Key Laboratory of Crop Water Use and Regulation, Ministry of Agriculture, Xinxiang 453002, Henan, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Liu
authors.affiliation: lrrigation Experiment Station of Water-conservancy Bureau in Xinjiang Production and Construction Corps, Urumqi 832002, China.
authors.forename: Gui-Sen
authors.initials: GS
authors.lastname: Yang
mesh_terms: D057914:Agricultural Irrigation / Q000379:methods*; D000383:Agriculture / Q000379:methods; D018533:Biomass; D002681:China; D017753:Ecosystem; D003368:Gossypium / Q000254:growth & development*; D018526:Plant Transpiration / Q000502:physiology*; D014867:Water / Q000032:analysis / Q000378:metabolism*
chemical_list: D014867:Water