不同间歇时间灌溉对水稻产量及水分利用效率的影响

Experimental Study on the Effects of Different Intermittent Irrigations on Yield and Water Use Efficiency of Rice

【目的】研究易推广、适宜江淮地区的水稻高产水分高效利用的节水灌溉模式,有利于当地水稻生产的可持续发展。【方法】于2015年和2016年在固定式水泥测坑内设置不同间歇灌溉时间处理W1(穗分化前水层落干后3~5 d,穗分化后水层落干1~3 d的补充灌溉)和W2(穗分化前水层落干后7~9 d,穗分化后水层落干3~5 d的补充灌溉),以常规淹灌(W0)为对照,研究间歇灌溉条件下补充灌溉的间歇时间及其对水稻产量及水分利用效率的影响。【结果】W0处理产量为8.01~9.40 t/hm2,W1、W2处理与W0处理无显著差异。与W0处理相比,W1、W2处理总需水量分别减少了3.64%~4.74%、5.63%~8.72%;W2处理的需水量低于W1、W0处理不同灌溉方式主要是通过影响穗分化期和灌浆结实期的需水量来影响总需水量,与W0处理相比,W1、W2处理穗分化期的需水量分别下降了0.66%~10.72%、4.54%~7.33%,灌浆结实期的需水量分别下降了4.67%~18.47%、20.76%~25.95%,且在2016年达到显著水平(P<0.05)。W1、W2处理较W0处理分别显著减少了7.50%~41.85%、31.00%~43.94%的灌水量,分别减少了1、1~2次灌水。2 a的灌水利用效率以W2处理下的最高(3.79~12.66 kg/m^3),分别较W0和W1处理提高了43.02%~98.74%、5.59%~22.26%;降水利用率也显著高于W0和W1处理。【结论】穗分化前水层落干后7~9 d,穗分化后水层落干3~5 d的补充灌溉方式能有效减少灌水量、灌排水次数,提高灌溉水利用效率和降水利用率,稳定水稻产量,是较为适合江淮地区的稻田高产水分高效利用的间歇灌溉方式。

【Objective】Improving irrigation water use efficiency has become increasingly pressing for developing sustainable irrigation,and the objective of this paper is to investigate experimentally the impact of different intermittent irrigations on yield and water use efficiency of rice.【Method】The field experiment was conducted at Jianghuai region in southeast China,in which we compared two intermittent irrigations:supplemental irrigation by keeping a water layer over the soil surface for 3~5 days prior to the panicle initiation and then another 13 days after the panicle initiation(W1),supplemental irrigation by keeping a water layer over the soil surface for 7~9 days before the panicle initiation and then another 3~5 days after the panicle initiation(W2).In each treatment,we measured grain yield and water use efficiency in both 2015 and 2016;the conventional flooding irrigation served as the control(W0).【Result】The rice yield in W0 was 8.01~9.40 t/hm2,not differing significantly from that in W1 and W2.Compared to W0,W1 and W2 reduced total evapotranspiration(ET)by 3.64%~4.74%and 5.63%~8.72%respectively,with the discrepancy between W1 and W2 caused mainly by their different impact on ET in the panicle initiation and gain-filling stages.Compared with W0,W1 and W2 reduced ET by 0.66%~10.72%and 4.54%~7.33%during the panicle stage,and by 4.67%~18.47%and 20.76%~25.95%during the gain-filling stage,respectively;the reduction in ET was significant in 2016.Compared to W0,W1 and W2 saved irrigation amount by 7.50%~41.85%and 31.00%~43.94%and irrigation times by 1 and 1~2,respectively.Apart from efficacy in using precipitation,W2 was also most efficient in using irrigation water(3.79~12.66 kg/m^3)and was 43.02%~98.74%and 5.59%~22.26%higher than W0 and W1,respectively.【Conclusion】Supplemental irrigation by keeping a water layer over soil surface for 7~9 days prior to the panicle initiation and then another 3~5 days after the panicle initiation can effectively reduce irrigation amount and frequency without compromising rice yield.It also improved use efficiency of both irrigation water and precipitation and is thus the optimal intermittent irrigation method for rice in Jianghuai region.