控释氮肥减量施用对南方丘陵地区春玉米土壤渗漏水氮素动态及其损失的影响

为提高我国南方丘陵地区旱地土壤作物种植的氮肥利用率,减少资源浪费和降低环境污染风险,通过采用田间小区定位试验进行土壤养分渗漏观测,研究比较了不施肥处理(T1)、普通尿素处理(T2)以及不同施氮量的控释氮肥处理(T3~T6)的TN、NO3-—N和NH4+—N的流失浓度变化及其损失负荷特征。结果表明:在168~240kg N/hm~2施氮水平变化内,渗漏水量在3 888~3 948L之间,即施肥量的增加或减少对渗漏体积的影响不显著(P0.05);控释氮肥处理T3的TN、NO3-—N和NH4+—N的平均流失浓度分别是32.66,29.41,0.26 mg/L,比等氮量施用的T2处理分别降低了24.99%(P0.01),25.56%(P0.01)和25.71%(P0.05);同样T3在损失负荷方面TN、NO3-—N和NH4+—N分别为53.07,47.14,0.47kg N/hm~2,较T2分别降低了24.10%(P0.01),25.62%(P0.01)和18.97%(P0.05)。当控释氮肥减氮10%,20%,30%时,其TN损失浓度为28.81,26.50,24.34mg/L,较T3分别降低了11.79%(P0.05),18.86%(P0.05),25.47%(P0.05);损失负荷为41.78,36.62,33.90kg N/hm~2,较T3分别降低了21.27%(P0.01),31.00%(P0.01),36.12(P0.01)。NO3-—N是渗漏氮素损失的关键成分,占TN损失负荷88.83%~92.75%,DON次之。控释氮肥在192kg N/hm~2的投入下能够有效的减少氮素渗漏损失,降低环境污染风险,并且还可以增产增效。

Effects of CRNF Application on Nitrogen Dynamics and Loss of Leachate Water in Spring Maize Soil in Hilly Area of South China

In order to improve the nitrogen use efficiency and reduce the resource waste and the risk of environmental pollution,a study on the leakage loss of controlled release nitrogen fertilizer (CRNF) application in hilly area of South China was conducted.The effects of CRNF (T3 ～ T6) application on nitrogen dynamics and loss of TN,NO3--N and NH4+-N in leachate water under different treatments in spring maize soil were explored.The results showed that the leakage water was 3 888～3 948 L when the nitrogen application rate was 168～240 kg N/hm2,hence fertilizer application rate had no significant effect on the leakage volume (P＞0.05).Average leaching loss concentration of TN,NO3--N and NH4+ N under T3 treatment were as follows 32.66 mg/L,29.41 mg/L,and 0.26 mg/L.Compared with the application of common urea (T2),T3 treatment with the same amount of nitrogen application rate decreased by 24.99％ (P＜0.01),25.56 ％ (P＜0.01) and 25.71％ (P＜0.05),respectively.Meanwhile,the loss load decreased by 24.10 ％(P＜0.01),25.62 ％(P＜0.01) and 18.97 ％(P＞0.05),respectively,and namely 53.07,47.14 and 0.47 kg N/hm2.When the nitrogen fertilizer application rate was reduced by 10％,20％％,30％,the corresponding average TN loss concentration were 28.81,26.50 and 24.34 mg/L,which decreased by 11.79％(P＞0.05),18.86％(P＜0.05),25.47％(P＜0.05)compared to T3.Similarly,the loss load were 41.78,36.62,and 33.90 kg N/hm2,which decreased by 21.27％(P＜0.01),31.00％(P＜0.01),36.12 (P＜0.01),respectively.NO3-N is the major component of leakage nitrogen loss,which accounted for 88.83 ％～92.75％ of TN loss load,and DON was also not negligible.During the planting of spring maize in dry land,the CRNF application rate with 192 kg/hm2 could effectively reduce the loss of nitrogen leaching and the risk of environmental pollution,and even increase yield and efficiency.