不同灌水和施氮对黄土性土壤中NO_3^--N迁移和淋失的影响

Effect of Different Irrigation Water and Nitrigen Rate on Transfer and Leach Soil NO_3^--N in Loess Soil

通过室内土柱渗透试验,研究了不同灌水和施氮对黄土性土壤中NO3--N迁移和淋失的影响。结果表明:土壤含水量随灌水量增大而增大,大灌水定额时,在近饱和土壤水分条件下,氮素淋失严重;在小灌水定额条件下,0-35 cm土层含水量显著减小,NO3--N未发生淋失;施氮量一定时,土壤剖面NO3--N含量随灌水量增大而减小,随土层深度增加呈显著增加趋势;土壤剖面NO3--N含量随施氮水平的增加有递增趋势、与土壤含水量成消长关系。土壤NO3--N累积量与施氮量、土层深度、渗透时间成正比,与灌水量成反比,符合多元非线性模型。因此,为减小NO3--N淋溶损失,从经济和环境效益方面考虑,黄土性土壤适宜灌水量应小于121 mm,次施氮量不宜高于2.40 mg/cm2。

Soil infiltration experiment was carried out to study the effect different irrigation water and nitrogen rate on transfer and leach soil NO3^--N in loess soil.The results indicated that soil water content increased with irrigation water quantity increase.In large irrigation quota,soil moisture downward migration rapidly in nearly saturated soil layer,nitrogen leach seriously.Under conditions of small irrigation quota,soil moisture in 0-35 cm reduced significantly,not occurring nitrogen leaching.When nitrogen rate is certain,NO3^--N content in soil profile decreases with the increasing of irrigation content and have significantly increasing trend with the increased depth of soil.NO3^--N content in soil profile have an increasing trend with increase of the nitrogen rate,and soil moisture is inversely relation with soil NO3^--N content.There have a positive correlation of soil nitrogen accumulation with the nitrogen rate,soil depth and infiltration time,and have a negative correlation with irrigation water good quantity,which can be described with multiple non-linear model.So in order to reduce nitrogen leaching losses,and consider the economic and environmental benefits,the reasonable rate of irrigation and application N were 80 mm and 1.80 mg/cm^2 respectively in loess soil.