不同种植年限果园土壤有机氮组分变化特征

Characteristics of soil organic nitrogen components of orchards with different planting ages

为了揭示不同种植年限(0、2、10、20和30 a)果园土壤有机氮组分变化规律,本文采用Bremner有机氮分级方法研究种植年限对果园土壤有机氮组分的影响。结果表明:耕作30年范围内果园土壤全氮含量随种植年限的延长而显著增加,增加的氮量在酸解未知态氮、非酸解性氮、氨态氮、氨基酸氮和氨基糖氮中的分配比例分别为38.9%、25.7%、20.5%、9.9%和4.9%;随着种植年限的延长,土壤有机氮组分中非酸性氮比例呈上升趋势,氨态氮和酸解未知态氮比例呈下降趋势,各有机氮组分比例的大小顺序也随之发生变化;非酸解性氮比例的提高降低了土壤有机氮矿化速率,影响土壤无机氮供应能力。

In this study, the Bremner method was used to measure soil organic N components and to clarify the characteristics of soil organic N components with different orchard planting ages （0, 2, 10, 20, and 30 years）. The results showed that the total N contents in the orchard soils increased with the planting age. The hydrolysable unidentified N, nonacid hydrolysable N, ammonium N, amino acid N and amino sugar N accounted for about 38.9%, 25.7%, 20.5%, 9.9% and 4.9% of the increased total N in soil, respectively. The percentage of non-acid hydrolysable N increased with the planting age, while the percentage of hydrolysable unidentified N and ammonium N decreased with the planting age. Thus, the sequence of organic N components in soil changed with the planting age. The organic N mineralization rate decreased with the increased percentage of nonacid hydrolysable N, affecting inorganic N supply rate in soil.