滴灌技术参数对南疆棉花生长和土壤水盐的影响

Effects of drip irrigation technical parameters on cotton growth, soil moisture and salinity in Southern Xinjiang

为确定最适宜南疆棉花生长的滴灌技术参数,于2018和2019年4-10月在新疆库尔勒31团(86°56′58″E,40°53′03″N)开展大田试验,试验设置3个灌溉定额(W1:60%ETc,W2:80%ETc,W3:100%ETc,ETc为作物蒸发蒸腾量)和2个滴头流量(D(1.8):1.8 L/h,D2.4:2.4 L/h),研究不同灌溉定额和滴头流量对棉花株高、茎粗、叶面积指数、干物质累积量等生长指标、产量及其构成要素(有效铃数、百铃质量)和土壤水盐分布的影响。结果表明:1)同一滴头流量下,W3处理棉花生长指标、产量及其构成要素显著高于W1和W2处理;W1处理灌溉水分利用效率和水分利用效率显著高于其他灌水处理。2)同一灌溉定额下,D2.4处理棉花生长指标、产量及其构成要素、水分利用效率和灌溉水分利用效率显著高于D1.8处理。2018和2019年,W1、W2和W3处理下,D2.4处理的产量比D1.8分别增加4.81%、8.39%、4.69%和4.98%、7.23%、11.06%。D2.4处理土壤含水率均匀性高于D1.8处理;0~40cm土壤含盐量随生育期推进呈上升趋势,随灌溉定额和滴头流量增加而降低。综合分析,灌溉定额为100%ETc、滴头流量为2.4 L/h时棉花生长较好,产量较高,2年最高产量分别为7 361.44和7 837.91 kg/hm2,是南疆棉花适宜的滴灌技术参数组合。研究结果可为指导该地区棉花节水控盐高效生产提供理论依据。

An optimal irrigation management needs to clarify the effects of technical parameters on the crop growth,dry matter accumulation,seed yield,and the distribution of water and salt in soil.In this study,a two-year field experiment was conducted from April to October in 2018 and 2019,to investigate the effects of various amount of drip irrigation and emitter discharge rate on cotton growth at the 31 st Regiment in Korla of Southern Xinjiang(86°56′58″E,40°53′03″N).Three levels of drip irrigation were designed,including the full irrigation(W3:100%ETc,ETc is the crop evapotranspiration),moderate irrigation(W2:80%ETc),and low irrigation(W1:60%ETc).Two of emitter discharge rate(1.8 and 2.4 L/h)were applied to explore the optimal combination of drip irrigation amount and emitter discharge rate for cotton production,resulting in a total of six treatments with three replicates.Cotton growth indexes were measured,including the yield and its components,soil water moisture,and soil salinity.The main results were as follows:1)There were significant effects of irrigation amount and emitter discharge rate on plant height,stem diameter,leaf area index,dry matter accumulation,yield and its components.In the bolling opening stage of 2018 and 2019,the plant height in the W1 treatment decreased by 10.40%and 11.22%,compared with that in the W3,respectively.The leaf area index in the W1 treatment was 22.52%and 44.16%lower than that in the W3.The plant height in the W1 treatment was 11.38%and 4.64%lower than that in the W3,when the emitter discharge rate was D2.4.The leaf area index in the W1 treatment was 24.55%and 53.83%lower than that in the W3.At the same rate of emitter discharge,the growth indexes,yield and its components of cotton increased with the increase of irrigation amount.Specifically,the cotton growth indexes,seed cotton yield and its components of W3 were significantly higher than those of W1 and W2.Under the same irrigation amount,the plant height,stem diameter,leaf area index,dry matter accumulation,effective boll number,100-boll weight,and seed cotton yield were higher at the emitter discharge rate of D2.4,compared with those of D1.8.In 2018 and 2019,the yields of three irrigations amount under D2.4 increased by 4.81%,8.39%,4.69%and 4.98%,7.23%and 11.06%,compared with those under D1.8.The corresponding water use efficiency under D2.4 was 13.48%,5.44%,8.99%and 5.61%,5.36%,0.84%higher than that under D1.8,respectively.2)The water use efficiency and irrigation water use efficiency decreased with the increase of irrigation amount.In W1 treatment,there was significantly higher than those of other irrigation treatments,at the same emitter discharge rate.The water use efficiency and irrigation water use efficiency at the emitter discharge rate of D2.4 were significantly higher than those D1.8 under the same irrigation amount.3)The irrigation amount and emitter discharge rate had significant effects on soil water content and salinity distribution.The soil water content in the W3 was higher than those of W1 and W2 at the same emitter discharge rate.The distribution of soil water content in the D2.4 was more uniform than that in the D1.8 under the same irrigation amount.In the salinity of 0-40 cm soil layer,a gradual accumulation trend occurred during the whole growing season of cotton.The soil salinity decreased with the increase of irrigation amount at the same emitter discharge rate.The soil salinity in the D2.4 was lower than that of D1.8.When the irrigation amount was 100%ETc and the emitter discharge rate was D2.4,the soil water content was higher,the horizontal distribution of soil profile was more uniform,and the soil salinity was lower,indicating an optimal combination of parameters for the cotton growth.These results demonstrate that the irrigation amount of W3(100%ETc)combined with emitter discharge rate of 2.4 L/h can be the optimal irrigation strategy for the cotton production in Southern Xinjaing,with the highest seed cotton yield of 7361.44 kg/hm2 in 2018,and 7837.91 kg/hm2 in 2019,respectively.This finding can provide a theoretical basis to guide the efficient cotton production with water saving and salt control in the Korla region of Southern Xinjiang,China.