灌溉对土壤硝态氮淋吸效应影响的研究

在陕北米脂县无定河谷地沙壤质土壤上进行了灌水量对土壤硝态氮的淋失和作物吸收效应影响的研究( 简称淋吸效应) 。结果表明,灌水量在0～4000m3/hm2范围内,与玉米产量和玉米吸N 量之间的关系均呈线性相关。土壤剖面中NO3--N 遗留量主要集中分布在0 ～60cm土层内,出现的高峰在40cm ;在0 ～80cm 土层内的NO3--N 遗留量随灌水量的增加而降低;80 ～320cm 土层内的NO3--N 与灌水量之间无明显相关,320 ～400cm 土层内NO3--N 是随灌水量的增加而增高。不同深度的土壤剖面中NO3--N 遗留量与灌水量之间均呈双曲线相关;氮素损失率以未灌溉和灌水量4000m3/hm2处理的为最低,据此提出了土壤NO3--N 淋吸效应的概念。

STUDY ON EFFECT OF IRRIGATION ON SOIL NITRATE LEACHING AND UPTAKE

The effect of irrigation on soil nitrate leaching and uptake was conducted with sandy loam soil in the valley of Wudian River. The main results showed as follows: there is a linear relationship between the amount of irrigation water and corn yield, and between the amount of irrgation water and uptake N by corn crop within the range of 0～4000m 3/hm 2 irrigation water. The NO₃^--N mainly concentrated in 0～60cm soil layer, the peak of which was at 40cm. The remained NO₃^--N in 0～80cm soil layer was decreased with the increase of irrigation water, and there is no relationship between the remain NO₃^--N and amount of irrigation water in 80～320cm soil layer, but the remain NO₃^--N was increased with the increase of irrgation water in 320～400cm soil layer. The relationship between the remained NO₃^--N and amount of irrigation water was hyperbola at the different depth of soil profile. The N lost from treatment without irrigation and with 4000m ³/hm² irrigation was lowest. The leaching loss of NO₃^--N could be decreased with the increase of large amount of irrigation water in right way, the main reasons of which were analysed and gave out the concept of NO₃^--N leaching and uptake effect.