塔里木灌区膜下滴灌的棉花需水量及节水效益

Cotton Water Requirements and Water Saving Benefit Under Mulched Drip Irrigation in Tarim Irrigated Area

为了确定适宜的灌溉制度,2008年通过田间灌溉试验,采用水量平衡法研究了塔里木灌区膜下滴灌棉花需水和耗水规律。以田间试验数据为基础,拟合了棉花的水分生产函数模型,分析评价了膜下滴灌棉花的节水效益。结果表明:塔里木灌区膜下滴灌棉花需水量为543mm,其中苗期252mm,蕾期186mm,花铃期316mm,吐絮期139mm。随滴灌量减小,耗水量减小。滴灌量影响棉花各生育阶段的耗水量及产量,并不影响耗水比例。相应于灌溉水利用效率最高点的滴灌量要低于产量最高点的,因此节水与增产产生矛盾,仅从节水角度考虑,滴灌量为3 091m3/hm2时,可以达到最大灌溉水利用效率,要获得最大产量,滴灌量应满足3 464m3/hm2。与漫灌相比,膜下滴灌节水增产效益明显。在同一灌溉量下,膜下滴灌增产30.2%,灌溉水利用效率提高30.2%,在同一产量水平下,节水29.3%,灌溉水利用效率提高41.5%。

The primary purpose of this research was to give suitable irrigation program according to the growth period and water requirement.A cotton field experiment with mulched drip irrigation was conducted in Tarim Irrigated Area of Xinjiang in 2008.Water balance method was adopted to investigate the water requirement and water consumption pattern of cotton under mulched drip irrigation in Tarim Irrigated Area.Statistical analysis of experimental data of irrigation indicates that the relationship between yield of cotton and irrigation presents a quadratic parabola.We fit the model of cotton water production on the basis of field experimental data of cotton.And the analysis on water saving benefit of cotton under mulched drip irrigation was carried out.Results indicate that water requirements for the irrigated cotton are 543 mm in Tarim Irrigated Area;the water requirement at the seedling stage is 252 mm,it is 186 mm at budding stage,it is 316 mm at bolling stage and it is 139 mm at wadding stage：the irrigation amount determines the spatial distribution of soil moisture and water consumption during cotton life cycle.However,water consumption at different growth stages was inconsistent with irrigation.Quantitatively,the water consumed by cotton decreases upon the increase of irrigation amount.From the perspective of water saving,the maximal water use efficiency can reach to 3 091m3/hm2.But the highest cotton yield demands 3 464m3/hm2 irrigation water.In summary,compared to the conventional drip irrigation,a number of benefits in water saving and yield increase were observed when using plastic mulch.At the same amount of irrigation,the cotton yield with plastic mulch was 30.2% higher than conventional practices,and the efficiency of water utilization increased by 30.2%.While at the same yield level,29.3% of water was saved by using plastic mulch,and the efficiency increased by 41.5%.