不同林龄顶坛花椒人工林土壤肥力变化规律

目的]探究顶坛花椒(Zanthoxylum planispinum var.dintanensis)人工林土壤肥力随林龄的变化，为林分培育措施的优化提供理论依据。方法]以5～7,10～12,20～22,28～32 a的顶坛花椒人工林为对象，运用Pearson相关性分析与主成分分析，结合Norm值，建立最小数据集以评价其土壤肥力。结果]不同林龄差异主要表现在土壤有机碳、全磷、全钙、真菌、微生物生物量氮、微生物生物量磷(p<0.05)。Pearson相关分析表明，有效钾与放线菌、微生物生物量磷呈显著正相关，微生物生物量氮与全磷、有效镁、有效锌呈显著正相关，表明土壤营养元素的积累可为微生物生长提供物质基础。不同林龄林分土壤肥力限制因子不同，5～7 a和10～12 a主要受有效钾、细菌、放线菌、微生物生物量磷支配；20～22 a主要受有机碳限制；28～32 a则为有效磷、全钙、真菌。土壤肥力综合指数为20～22 a(1.06)>5～7 a(-0.05)>10～12 a(-0.42)>28～32 a(-0.58)。结论]20～22 a及以后的林分养分吸收能力下降，...

Change of Soil Fertility in Zanthoxylum planispinum var. dintanensis Plantation with Different Ages

Objective] Exploring the change of soil fertility in Zanthoxylum planispinum var. dintanensis plantation with forest ages can provide a theoretical basis for the optimization of stand cultivation measures. Methods] The study took Zanthoxylum planispinum var. dintanensis plantations with ages of 5～7, 10～12, 20～22, 28～32-year groups as the objects, and the Pearson's correlation and principal component analysis were carried out in combination with norm value. The minimum data set was finally established for comprehensive evaluation of soil fertility. Results] The differences of soil fertility of different forest ages were mainly manifested in soil organic carbon, total phosphorus, total calcium, fungi, microbial biomass nitrogen, microbial biomass phosphorus. Pearson correlation analysis showed that available potassium was significantly positively correlated with actinomycete and microbial biomass phosphorus; microbial biomass nitrogen was significantly positively correlated with total phosphorus, available magnesium and available zinc, indicated that the accumulation of soil nutrients could provide a material basis for microbial growth. The limiting factors of soil fertility in different ages were different, in which 5～7, 10～12 years groups were mainly dominated by available potassium, bacteria, actinomycete and microbial biomass phosphorus; 20～22 years group was mainly limited by soil organic carbon; the important restrictive factors in 28～32 years group were available phosphorus, total calcium and fungi. The integrated fertility index decreased in the order: 20～22 years(1.06)>5～7 years(-0.05)>10～12 years(-0.42)>28～32 years(-0.58)group. Conclusion] The nutrient absorption capacity of the plantation aged 20～22 years and beyond decreased, and the plantation below this forest age should be selected as the main management target.