花铃期减量施肥对棉田径流养分流失的影响

Reducing Fertilization at the Blooming Stage Can Alleviate Nitrogen Loss with Surface Runoff in Cotton Field

为更好制定雨季棉田养分管理措施,以当地常规施肥量为对照(CK),设置80%常规施肥量(T1)和60%常规施肥量(T2)2个处理,探讨减量施肥对棉田地表径流养分流失的影响。结果表明,与CK相比,T1和T2处理下随强降雨产生的棉田地表径流中,TN、NH4+-N、NO3--N、TP、DP、DRP平均质量浓度均显著降低,其中T1处理的TN、TP平均质量浓度减少了2.50 mg/L和0.183 mg/L,T2处理分别减少了3.41 mg/L和0.234 mg/L。CK、T1和T2处理的棉花产量分别为3 500、3 364、3 242 kg/hm^2,其中T1处理的棉花产量与CK无显著性差异,而T2处理的棉花产量与CK相比显著降低。故建议棉花花铃期施肥量应为常规追肥量的80%,即505 kg/hm^2,以减轻由养分流失所造成的农业面源污染。

Field experiment was conducted to investigate the impact of fertilization on nitrogen loss from surface runoff in attempts to improve nutrient management during rainy season in cotton field. Conventional fertilization used by local farmers was taken as the control （CK）, and twofertilization treatments, oneusing 80% of CK （T1） and the other using 60% of CK （T2）, were examined. The results showed that, compared with the CK, T1 and T2 significantly reduced the average concentration of total nitrogen （TN）, NH4~, NO3-, total P, DP and DRP in the sur- face runoff after heavy rainfalls. The decrease in TN and TP was 2.50 and 0.183 mg/L respectively under T1, and 3.41 and 0.234 mg/L respectively under T2. The yield under CK, T1 and T2 was 3 500, 3 364 and 3 242 kg/hm2, respectively. The yield in T1 and CK was comparable, but there was a yield loss in T2. Therefore, reducing fertil- ization at the blooming and the boll-forming stages by 20% （505 kg/hm2） from the conventional fertilization could alleviate nitrogen loss from the surface runoff without scarifying yield.