稻麦两熟农田稻季养分径流流失特征

采用田间小区定位试验研究了自然降雨条件下江苏稻麦两熟农田稻季养分径流流失规律。结果表明：稻季径流水量可达5705.55m3·hm-2;常规施肥（T0）条件下,稻田径流流失全N（TN）、全P（TP）和速效K（AK）的总量分别为11.29、0.19和13.22kg·hm^-2,流失率分别为3.8%、0.21%和9.8%;径流水中全N和速效K质量浓度随距施肥时间的延长而呈逐渐下降趋势;较常规施肥处理而言,秸秆还田（T1）和还田减肥（T2）处理不仅能够有效降低径流水中TN、TP和AK质量浓度,而且能够减少稻季养分径流流失总量,分别减少13.48%、17.55%,25.00%、31.25%和22.69%、53.48%,并降低养分流失率,分别达13.16%、-2.63%,23.81%、14.29%和22.45%、41.84%。

The Characteristics of surface runoff losses of soil nitrogenand phosphorus during rice season in intensiverice-wheat rotation field

Field plot experiment was carried out to study the characteristics of surface runoff of nutrients losses during the paddy season of intensive rice-wheat double-cropping season of Jiangsu province under natural rainfall conditions.The results showed that the total volume of runoff water reached 5 705.55 m3·hm^-2 during the whole paddy season.Under conventional fertilization condi-tions（T0）,the total runoff losses of TN,TP and AK reached 11.29,0.19 and 13.22 kg·hm^-2,and the rates of nutrients losses reached 3.8%,0.21% and 9.8%,respectively.The concentrations of TN and AK in the runoff water showed a gradual downward trend along with the extension of time from the fertilizer.Compared with T0 treatment,wheat straw returning（T1）,wheat straw returning and reducing fertilizer（T2）not only effectively reduced the concentrations of TN,TP and AK,but also reduced the quantities of TN,TP and AK losses in the runoff water during the paddy season,decreased 13.48%,17.55%（TN）,25.00%,31.25%（TP）and 22.69%,53.48%（AK）,respectively;furthermore,these treatments reduced the rate of nutrients losses,which decreased 13.16%,-2.63%（TN）,23.81%,14.29%（TP）and 22.45%,41.84%（K）,respectively.