陈山红心杉连栽林地土壤肥力综合评价

【目的】研究红心杉连栽对地力和林分生产力的影响,为红心杉人工林的可持续经营提供数据参考。【方法】选取立地条件相同的第1(G1)、2(G2)、3(G3)代红心杉人工幼林林地为研究对象,采用空间替换时间的方法,测定第1、2、3代红心杉幼林地0~20 cm,20~40 cm,40~60 cm土层中的土壤酶活性及主要理化性质,利用主成分分析法综合评估不同代次红心杉幼林林地的土壤肥力,探究与分析连栽红心杉林地肥力下降的主要影响因子。【结果】土壤肥力的综合评价指数F值的变化范围为5.993^-4.436,23个评价指标通过“降维”成3个主成分,累计贡献率达88.913%,其中,第1主成分贡献率为71.862%,第2主成分的贡献率为9.123%,第3主成分的贡献率仅有7.927%;随着连栽代次增加和土层加深,土壤水分和孔隙指标均呈降低趋势;大量元素、有效微量元素、脲酶和磷酸酶活在第1、2、3代之间均具有显著差异(P<0.05)。【结论】在当前的种植方式下,随着红心杉连栽代次的增加,土壤肥力和容蓄能力下降,脲酶、磷酸酶、全P、碱解N、速效K、有效Cu、有效Mn和有效Fe是影响土壤肥力的关键要素。

Study on the assessment of soil fertility in continuous planting of Cunninghamia lanceolata in Chenshan forest farm

【Objective】In order to study the effect of continuous planting of red-heart China fir on soil fertility and stand productivity,and to provide data reference for sustainable management of red-heart China fir plantation.【Method】The first(G1),the second(G2)and the third(G3)generation of red-heart China fir plantations with the same site conditions were selected as the research objects.The soil enzyme activity and the main physical and chemical properties of the first,the second and the third generation of red-heart China fir plantations in the soil layers of 0-20cm,20-40cm and 40-60cm were measured by the method of space replacement time.The soil of different generations of red-heart China fir plantations was evaluated by the principal component analysis soil fertility,to explore and analyze the main factors affecting the decline of forest fertility.【Result】The comprehensive evaluation index F of soil fertility ranged from 5.993 to-4.436.23 evaluation indexes were divided into three main components through“dimension reduction”,and the cumulative contribution rate was 88.913%,among which the contribution rate of the first main component was 71.862%,the contribution rate of the second main component was 9.123%,and the contribution rate of the third main component was only 7.927%.With the increase of successive generations and the deepening of soil layer,the soil moisture and porosity were increased.There were significant differences among the first,second and third generations in the activities of many elements,effective trace elements,urease and phosphatase(P<0.05).【Conclusion】Under the current planting mode,with the increase of successive generations of red-heart China fir,the soil fertility and storage capacity decrease.Urease,phosphatase,total P,alkali hydrolyzed n,available K,available Cu,available Mn and available Fe are the key factors affecting the soil fertility.