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为研究黄土高原植被恢复、退耕还林过程中根际分泌的柠檬酸对土壤养分、pH的影响,通过对石灰性土壤塿土施用外源柠檬酸,模拟根际柠檬酸环境。结果表明,施用外源柠檬酸后:(1)土壤全氮含量随柠檬酸施用天数的增加大体上有升高的趋势,土壤水解性氮含量随时间、外源柠檬酸浓度的增加而递减;(2)土壤全磷含量变化不大;(3)有效磷含量变化以40 d左右为过渡,前期土样随外源柠檬酸浓度的升高而减少,后期随柠檬酸升高而增加;(4)土壤pH与有效磷含量的变化规律呈极显著负相关;(5)有机质含量变化规律复杂。柠檬酸对土壤养分各指标的影响不同,但相互联系。
In order to study the effect of rhizosphere-secreted citric acid on soil nutrient and pH during the process of vegetation restoration and returning farmland to forestland, the citric acid environment was simulated by applying exogenous citric acid on calcareous soil. The results showed that after application of exogenous citric acid: (1) Soil total nitrogen content increased with the increase of citric acid application days, and the soil hydrolyzable nitrogen content decreased with the increase of time and exogenous citric acid concentration. (2) The content of total phosphorus in soil did not change much; (3) The content of available phosphorus changed about 40 d, the content of soil decreased with the concentration of exogenous citric acid in the early stage and increased with the increase of citric acid in later stage; 4) The soil pH and the available phosphorus content showed a very significant negative correlation; (5) The variation of organic matter content was complex. Citric acid has different effects on the indicators of soil nutrients, but they are interrelated.