川南毛竹林生态系统养分动态分析

Analysis of nutrient input and output in a Phyllostachys pubescens ecosystem of southern Sichuan province

以目标产量和现实产量为基础,分别计算了川南毛竹林生态系统中N、P、K、Ca、Mg、Si等养分年亏损量。结果显示:(1)当年采伐量为22.5t/hm2时,6种元素的养分输出总量为216.78kg/hm2,其中N为93.13kg/hm2、Si为57.61kg/hm2、K为38.04kg/hm2、Ca为11.39kg/hm2、Mg为8.33kg/hm2,P为8.28kg/hm2,采伐时若将竹叶归还林地,养分年总输出量将减少73.3kg/hm2;(2)在现有的经营强度下(即年均采伐产量为9.0t/hm2)时,6种养分亏损总量为:7.96kg/hm2,各元素亏损率的排序为:Si(29.91%)、P(27.19%)、N(22.97%)、Mg(8.51%)、K(7.60%);(3)结合各养分在土壤中贮量及其亏损状况分析表明,川南毛竹林地施用P肥对提高毛竹产量的效果最直接,但补充K、Si、Mg等养分是防止毛竹林地力衰退、维持毛竹林经营可持续性的必要措施和手段。

The annual deficits of N, P, K, Ca, Mg and Si in a Phyllostachys pubescens ecosystem of southern Sichuan were calculated based on expected and realized yield in this paper. Results showed that： （1）With annual yield at 22.5 t/hm2, the total annual output of all six nutrients was 216.78 kg/hm2, of which contribution of N, Si, K, Ca, Mg and P were 93.13, 57.61, 38.04, 11.39, 8.33 and 8.28 kg/hm2 respectively, and the 73.3 kg/hm2 per annual would reduce nutrient loss through by returning bamboo leave back to the field. （2）According to the realized yield of 9 t/hm2, the deficit was 29.91 % for Si, 27.19 % for P, 22.97 % for N, 8.51 % for Mg, and 7.60 % for K in descending order. （3）After analyzing the elements in soil and their deficiency, two conclusions could be drawn that application of P fertilizer has the most direct effect for improving P.pubescens production, and supplementation of nutrients such as K, Si and Mg is essential for preventing fertility decline and maintaining the sustainability of P.pubescens production.