滇中地区典型公益林林分土壤养分及肥力研究

Soil Nutrients and Fertility of Typical Public Welfare Forest in Central Yunnan

采用野外调查和室内分析相结合的方法,对滇中地区4种典型公益林(旱冬瓜林、云南松林、元江栲林、锥连栎林)的不同林分、坡向和土层的土壤养分及肥力状况进行综合分析。结果显示:(1)旱冬瓜林土壤全氮(TN)、全磷(TP)、全钾(TK)及有效磷(AP)显著高于其他林分,而有机质(SOM)、水解性氮(AN)表现为元江栲林最高,土壤速效钾(AK)则表现为锥连栎和旱冬瓜林较高;旱冬瓜、元江栲、锥连栎3种林分土壤TN、TP、TK、AN、AP基本表现为阴坡>阳坡,而云南松林的TK、SOM、AP则表现为阳坡>阴坡;随着土壤层次的加深,各样地土壤TN、TP、AN、AP、AK、SOM均逐渐降低。(2)由内梅罗指数分析可知,阴坡土壤肥力表现为旱冬瓜>云南松>锥连栎>元江栲,阳坡表现为云南松>旱冬瓜>元江栲>锥连栎,且4种林分的土壤肥力均表现为阴坡>阳坡。(3)三因素方差分析显示,林分、坡向、土层及其交互作用对土壤养分均影响显著(P<0.05)。土壤C、N、P化学计量特征与内梅罗指数综合分析可知,土壤P为锥连栎林的限制因子,土壤N、K为元江栲林的限制因子,建议锥连栎林及时补充P元素,元江栲林及时补充N、K元素。

Based on the combination of field investigation and laboratory analysis,the soil nutrients and fertility of different forest types,slope aspect,and soil layer depths of four kinds of typical public welfare forests(Alnus nepalensis,Pinus yunnanensis,Castanopsis orthacantha and Quercus franchetii)were comprehensively analyzed.The results showed that:(1)the soil total nitrogen,total phosphorus,total potassium,available phosphorus in A.nepalensis were significantly higher than those in other forests,In terms of soil organic matter and available nitrogen,C.orthacantha had the highest value.Q.franchetii and A.nepalensis had the best performance in terms of soil available potassium;The soil total nitrogen,total phosphorus,total potassium,available nitrogen,available phosphorus of A.nepalensis,C.orthacantha,and Q.franchetii were richer in shade slope than those in sunny slope.However,the soil total potassium,organic matter and available phosphorus of P.yunnanensis had a higher content in sunny slope than shade slope;the soil total nitrogen,total phosphorus,available nitrogen,available phosphorus and available potassium decreased gradually with the deepening of soil layer.(2)According to the analysis of nemerow index,soil fertility in shade slope is sequenced as A.nepalensis>P.yunnanensis>Q.franchetii>C.orthacantha,while that in sunny slope was sequenced as P.yunnanensis>A.nepalensis>C.orthacantha>Q.franchetii.Soil fertility of the four forests showed the sequence of shade slope>sunny slope;(3)variance analysis of three factor showed that forest types,slope aspect,soil layer depth and their interaction had significant impact on soil nutrients(P<0.05).As per the comprehensive analysis of Carbon,nitrogen and phosphorus stoichiometry as well as nemerow index,soil P is the limiting factor of Q.franchetii,and soil N and K are the limiting factor of C.orthacantha,and the Q.franchetii should supplement P elements in time,C.orthacantha should supplemented with N and K elements in time.