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本文报导了1983年以来,连续四年对作物根层(0—100cm)土壤剖面残留无机态氮(一般称为 Nmin)的动态观测。结果表明:旱地 Nmin 中 NO_3-N 比例高,而且其动态趋势与 Nmin 的动态趋势大致相同,可以用 NO_3-N 表征旱地 Nmin动态及土壤速效氮的水平。施用氮磷肥、灌溉、降水及作物吸收都影响 Nmin 含量及动态。施氮肥量低时,NO_3-N 主要在0—60cm 土层上下移动;施氮肥量高时,NO_3-N 主要在0—80cm 土层上下移动。北京地区冬小麦生长期中,NO_3-N 淋浴不强烈,可以用作物根层土壤剖面 NO_3-N 含量作为土壤对小麦氮素供应水平的指标。
This article reports the dynamic observation of the residual inorganic nitrogen (generally called Nmin) in the soil profile (0-100cm) of the crop for three consecutive years since 1983. The results showed that the proportion of NO_3-N in dry land was high, and its dynamic tendency was similar to that of Nmin. NO_3-N could be used to characterize the dynamics of Nmin and soil available nitrogen. Application of nitrogen and phosphorus fertilizer, irrigation, precipitation and crop absorption all affect Nmin content and dynamics. When the amount of nitrogen fertilizer was low, NO 3 -N mainly moved up and down in 0-60 cm soil layer. When the amount of nitrogen fertilizer was high, NO 3 -N mainly moved up and down in 0-80 cm soil layer. During winter wheat growing season in Beijing, the NO_3-N shower is not strong, and the content of NO_3-N in soil profile can be used as an indicator of soil nitrogen supply to wheat.