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在生物量、生产力和水量平衡及养分分析的基础上，系统研究了黄土残塬沟壑区刺槐人工林生态系统的养分循环过程。结果表明：生态系统中养分元素总贮量为Ｎ１０．９４０ｔ／ｈｍ２，Ｐ３．７５５ｔ／ｈｍ２，Ｋ１５４．６１１ｔ／ｈｍ２，Ｃａ１６９．０９２ｔ／ｈｍ２，Ｍｇ１８．４３５ｔ／ｈｍ２，Ｓ１．４８７ｔ／ｈｍ２；生态系统内养分生物循环遵循Ｃａ＞Ｎ＞Ｋ＞Ｍｇ＞Ｐ＞Ｓ的顺序；刺槐生产１ｔ干物质需要从土壤吸收Ｎ１１．６７ｋｇ，Ｐ０．７２ｋｇ，Ｋ３．６６ｋｇ，Ｃａ１５．０８ｋｇ，Ｍｇ２．２５ｋｇ，Ｓ０．３４ｋｇ；经过循环利用，生态系统年净积累量Ｎ１．８０７３ｋｇ／ｈｍ２，Ｐ０．２１０６ｋｇ／ｈｍ２，Ｋ１．３７５６ｋｇ／ｈｍ２，Ｃａ２．７８８１ｋｇ／ｈｍ２，Ｍｇ０．４４０ｋｇ／ｈｍ２，Ｓ０．０６２１ｋｇ／ｈｍ２，根层土壤却年净亏损Ｎ８９．６９６ｋｇ／ｈｍ２，Ｐ５．４９２ｋｇ／ｈｍ２，Ｋ３４．４７９ｋｇ／ｈｍ２，Ｃａ８８．９９１ｋｇ／ｈｍ２，Ｍｇ１５．２７０ｋｇ／ｈｍ２，Ｓ２．５１１ｋｇ／ｈｍ２。此外，所建立的该生态系统的养分动态模拟模型，可用于对各分室养分贮量动态的预测。
On the basis of biomass, productivity and water balance and nutrient analysis, the nutrient cycle of Robinia pseudoacacia plantation ecosystem in the gully area of Loess Plateau was systematically studied. The results showed that the total nutrient elements in the ecosystem were N10.940t / hm2, P3.755t / hm2, K154.611t / hm2, Ca169.092t / hm2, Mg18.435t / hm2 and S1.487t / hm2. The internal nutrient cycling followed the order of Ca> N> K> Mg> P> S. The production of 1t dry matter by R. pseudoacacia needed to absorb N11.67kg, P0.72kg, K3.66kg, Ca15.08kg, Mg2.25kg, S0 from the soil. 34kg; After recycling, the annual net ecosystem accumulation N1.8073kg / hm2, P0.2106kg / hm2, K1.3756kg / hm2, Ca2.7881kg / hm2, Mg0.440kg / hm2, S0.0621kg / hm2, root layer Net annual net loss of soil N89.696kg / hm2, P5.492kg / hm2, 34.479kg / hm2, Ca88.991kg / hm2, Mg15.270kg / hm2, S2.511kg / hm2. In addition, the established model of nutrient dynamic simulation of the ecosystem can be used to predict the dynamic nutrient storage in each sub-compartment.