甘肃陇东旱塬不同树龄苹果园矿质氮的分布和积累特征

Distribution and accumulation of mineral nitrogen in apple orchard soils in dry plateau of eastern Gansu Province

对甘肃陇东地区不同树龄苹果园土壤矿质氮的分布和积累特征进行了研究.结果表明:土壤铵态氮含量随着苹果树龄的增大呈上升趋势,2～3年生、5年生、10年生、15年生、20年生、22年生果园0～120cm土层铵态氮含量分别为3.3、5.8、6.5、9.1、12.1和15.3mg·kg-1;不同树龄果园0～60cm土层铵态氮含量大于60～120cm土层.不同树龄果园硝态氮含量在0～40cm土层相对较低,随土层深度增加,其含量迅速增加;随着种植年限增加,不同苹果园硝态氮累积量也呈显著增加趋势,22年生果园0～120cm土层硝态氮累积量达到2602.5kg·hm-2.旱塬苹果园表现为土壤铵态氮呈浅层积累、而硝态氮呈深层积累的特征.

This paper studied the distribution and accumulation characteristics of mineral nitrogen in the soils of different years old apple orchards in dry plateau of eastern Gansu Province. The soil ammonium nitrogen content was increased with the increase of planting year. In the 2-3, 5, 10, 15, 20, and 22 years old apple orchards, the ammonium nitrogen content in 0-120 cm soil layer was 3.3, 5.8, 6.5, 9.1, 12.1, and 15.3 mg·kg^-1, respectively, and 0-60 cm soil layer had a higher ammonium nitrogen content than 60-120 cm soil layer. For all the apple orchards, the nitrate nitrogen content in 0-40 cm soil layer was relatively low, but increased with increasing depth. The soil nitrate nitrogen content also increased with the increase of planting year, which reached 2602.5 kg·hm^-2 in the 0-120 cm soil layer of 22 years old apple orchard. It was concluded that in the apple orchards in dry plateau of eastern Gansu Province, soil ammonium nitrogen was more accumulated in upper layers, while nitrate nitrogen was more accumulated in deeper layers.