不同水氮供应对菜地土壤硝态氮累积的影响

通过田间小区和土柱模拟试验相结合的方法研究了不同水氮供应对菜地土壤硝态氮淋溶的影响，结果表明，在田间小区和土柱模拟试验中，硝态氮在1m土层内出现一个累积峰，并且随着灌水量的增加累积峰逐渐下移；在相同灌水量下，随着氮肥施用量增加两个试验1m土壤中硝态氮储量均增多。在田间小区试验中，当施氮量低于270kg/hm^2时，相同的施氮量下，150、250、350mm^3个水平灌水量下1m土体内硝态氮储量多少为250mm〉150mm〉350mm，当施氮量超过270k加m^2时，土体内硝态氮累积量随着灌水量的增加而减少。在土柱模拟试验中，在相同的施氮量下，1m土体硝态氮的储量随着灌水量的增加而增加。

Effect of Water and Nitrogen Supply on Nitrate Leaching in Soil

Field plot and column experiments were conducted for the different water and nitrogen supply scheme on nitrate accumulation in the soil. The results showed there was a peak value of accumulation in the lm soil layer in both field plot and column experiments, which walked down the soil profile with higher water supply. At the same water supply, the accumulation of nitrate in lm soil profile of field plot and column increased with higher nitrogenous fertilizer application. At the same nitrogenous fertilizer supply, when N application was below 270 kg/hm2 in field plot experiments, the order of nitrate accumulation of lm soil layer is 250 mm > 150 mm > 350 mm; when N application was above 270 kg/hm2, the nitrate accumulation of lm soil layer decreased with increased higher water supply. At the same nitrogenous fertilizer supply, the accumulation of nitrate in lm soil profile increased with increased higher water supply.