控制灌水对华北高产区土壤硝态氮累积的影响

在长期水分试验的基础上,研究了不同灌溉处理下小麦—玉米两季作物收获后的土壤含水量和剖面硝态氮的累积分布。结果表明:不同的灌溉量对小麦季0~200cm土层含水量产生明显影响,而玉米季和深层土壤含水量没有显著差异。相同的肥料施入水平下,不同灌溉量会造成土壤NO3--N的累积差异,硝态氮的累积量随着灌溉降水量的增加呈下降趋势。灌溉量的多少决定了土壤剖面硝态氮的分布,高灌水量使得各土层硝态氮的含量均低于15mg/kg,且在土壤剖面中的分布没有明显差异;中等程度灌溉水平下,260cm以下土壤硝态氮含量最高;低的灌溉量使得土壤硝态氮大量累积在0~260cm土层。

Effects of Controlled Irrigation on Nitrate Accumulation in North China

Based on the long-term field experiment, the effects of different water input on the soil water content after the harvest of crop, the distribution and accumulation of NO~-_3-N were studied. The results showed th at different water input only influenced soil water content in the depth of 0~20 0 cm in 2003 wheat season, there was no distinct difference between different tr eatments on deep soil layer and in 2003 corn season. Under the same fertilizer i nput level, different water input made different nitrate accumulation: a large a mount of water input made a little NO~-_3-N accumulate in the soil profile an d the amount of NO~-_3-N accumulated in the soil profile will be increased wi th amount of water input decreased. Commonly, the nitrate distribution in the so il profile were according with the amount of irrigation. Lots of irrigation made the content of nitrate in the soil were less than 15 mg/kg. Low irrigation made lots of nitrate accumulated in the layer of 0~260 cm, under 260 cm soil depth the nitrate content of middle irrigation w ere the highest.