不同灌溉方式和施氮水平对土体硝酸盐累积和淋失的影响

以华北平原冬小麦-夏玉米轮作体系为对象，研究不同灌溉方式（漫灌、喷灌）和施氮水平对土壤NO3^- -N的时空变化的影响.研究结果表明，与漫灌方式相比，喷灌在一定程度上减少了土壤NO3^- -N向土壤深层的累积；玉米季土壤深层累积大量NO3^- -N，漫灌方式和高施氮量（400kg·hm^-2·a^-1和600kg·hm^-2·a^-1）均显著增加了冬小麦－夏玉米轮作体系土壤NO3^- -N的淋洗，当施氮量在200kg·hm^-2·a^-1以下时，土壤中NO3^- -N的淋洗量与不施氮处理差异不显著．因此，合理灌溉和科学施肥是农业可持续发展的重要保证．

EFFECTS OF DIFFERENT IRRIGATION METHODS AND NITROGEN APPLICATION RATE ON SOIL NITRATE ACCUMULATION AND LEACHING IN SOIL PROFILE

This study performed effects of two irrigation （flooding and drip） with four rates application of N （0, 200,400,600 kg·hm^-2·a^-1） on soil NO3^- -N leaching of a winter wheat - svmmer maize rotation system in Huantai, Shandong Province, from Oct. 2003 to Oct. 2004. The results demonstrated drip irrigation increased the accumulation of soil NO3^- -N and minimized its further leaching to soil deep layer. In summer maize season, mass of soil NO3^- -N was accumulated and leached with great precipitation out of 120 cm soil layer. Under low N application （0- 200 kg·hm^-2·a^-1 ）, there was no significant difference tested on soil NO3- - N leaching amount, however, flooding irrigation and high N application （400 and 600 kg·hm^-2·a^-1） increased the leaching amount of soil NO3^- -N significantly （P 〈 0.05）. Our suggestion was that rational irrigation and fertilization were the key strategy for the sustainable development of agriculture.