渭北旱塬苹果园土壤矿质氮累积与分布研究

Mineral N accumulation and distribution of apple orchard soil on the Weibei dryland

对渭北早塬6～37龄苹果园土壤剖面中硝态氮和铵态氮的含量进行了分析测定，以了解不同树龄，不同剖面深度土壤矿质氮累积与分布状况。结果表明，不同种植年限苹果园0～400cm剖面土体中，氨态氮的含量和分布保持相对稳定；硝态氮含量和分布变化显著，含量在0．31～195．32mg／kg之间。土体剖面硝态氮的累积量呈显著增加的趋势，累积层出现在40～260cm土层，最高含量出现在15龄果园的100～120cm土层中。其值为195．32mg／kg。土壤剖面累积大量的硝态氮，可能会造成潜在的环境问题。

The content of NO3^- - N and NH4^ ＋ - N was determined in the soil profile of 6 to 37 age apple orchard on the Weibei dryland. The results showed that the content and distribution of NH4^ ＋ - N maintain relatively stable in the depths of 0 - 400 cm soil profile with different planting years. The content and distribution of nitrate nitrogen varied significantly, and the content of nitrate nitrogen was 0.31 - 195.32 mg/kg. The accumulation of nitrate nitrogen increased significantly, which was located in 40-260 cm depths, and the maximum nitrate N content was 195.32 mg/kg in 100 - 120 cm depths of 15 age orchard. Large accumulation of nitrate N in the soil profile might lead to potential environmental pollution.