不同灌排调控模式下水肥流失规律

Study of moving and transforming law of water and fertilizer under different treatments of irrigation and drainage

针对我国灌排面积不断增加、水资源利用效率不高、化肥流失严重等问题,结合田间对比试验,考虑节水灌溉与控制排水的协同效应,通过控制变量法研究灌排因素对农田排水量和作物产量的影响以及不同模式下土壤水中氮磷的迁移转化规律,发现控制排水-浅灌深蓄(G_1L_1)灌排组合下的排水量分别比控制排水-浅勤灌溉(G_1L_2)、自然排水-浅灌深蓄(G_2L_1)、自然排水-浅勤灌溉(G_2L_2)灌排组合下的排水量减少5.76%、2.80%、12.70%,G_1L_1的灌排组合更有利于控制田间排水量;G_1L_1模式下的作物产量分别比G_1L_2、G_2L_1、G_2L_2模式下的产量高7.59%、44.2%、48.91%,G_1L_1的调控模式更有利于提高作物产量.由此可知,G_1L_1的灌排调控模式为优选模式,其合理地调控了土壤水分,高效地利用了水分和养分,促使了水稻植株合理生长,实现了节水高产.

A series of field contrast experiments were conducted in southern rice area because irrigation and drainage area increases constantly,water efficiency is not high,fertilizer losses are so severe that downstream rivers and lakes are contaminated.Based on these experiments,this paper investigates the drainage situation,crop production,and the moving and transforming law of nitrogen（N）and phosphorus（P）under different treatments of irrigation and drainage,which considers the synergistic effects of water-saving irrigation and controlled drainage as well as uses control variate method.The results show that compared with uncontrolled drainage and shallow-irrigation and deep-sluice mode（G_1L_2）,controlled drainage and shallow-wet irrigation mode（G_2L_1）,uncontrolled drainage and shallow-wet irrigation mode（G_2L_2）,the discharge of controlled drainage and shallow-irrigation and deep-sluice mode（G_1L_1）decreases 5.76%,2.80%,12.70% respectively;and the yield increases 7.59%,44.2%,48.91%.Therefore,the irrigation and drainage combination of G_1L_1 is the best mode;that controls the soil moisture reasonably,uses the moisture and nutrient efficiently,encourages rice growing,and realizes water-saving and high-yield.