石漠化演替过程中土壤肥力质量综合评价

Comprehensive evaluation on soil fertility quality in process of rocky desertification

通过对湖南省中部地区不同石漠化程度的样地进行植被调查及土壤样品分析,并结合主成分分析方法,探讨了石漠化(RD)演替对土壤综合肥力的影响。结果表明:石漠化演替对土壤相关肥力指标有不同程度的影响,其中有机质(OM)和全氮(TN)变化规律为潜在石漠化(PRD)>轻度石漠化(LRD)>中度石漠化(MRD)>重度石漠化(SRD),其它肥力指标变化与石漠化演替方向不完全一致;石漠化演替中土壤微生物量(C、N、P)变化幅度较大,分别为251.08～124.26、31.40～69.42、2.13～4.45 mg.kg-1;土壤综合肥力大小为PRD>MRD>LRD>SRD;土壤OM、TN、全磷(TP)、阳离子交换量(CEC)、微生物量碳(MBC)、微生物量氮(MBN)、微生物量磷(MBP)、容重(BD)与综合肥力关系密切,可作为石漠化土壤肥力评价的核心指标。土壤肥力退化与石漠化演替方向基本一致,但地区差异和人为干预也对石漠化土壤肥力产生巨大影响。

By investigating the stands and analyzing the soil samples that with different rocky desertification（RD） degree in the midland of Hunan province,combining with the principal component analysis method,the effects of the succession of RD on soil comprehensive fertility.The results show that the succession of RD had different impacts on soil fertility indicators,the changing regulation of organic matter and total nitrogen content in different RD areas was： Potential RD（PRD） Light RD（LRD） Moderate RD（MRD） Severe RD（SRD）,the other fertility indicators’ changing regulations were not totally consistent with the succession of RD;In the process of RD,the microbial biomass in the soil（C,N and P fertilizer） ranged from 251.08 to 124.26（mg.kg-1）,31.40 to 69.42（mg.kg-1）,2.13 to 4.45（mg.kg-1）,respectively;The sequencing of soil comprehensive fertility in different RD soils was： PRD MRD LRD SRD;The OM,TN,total phosphorus（TP）,cation exchange capacity（CEC）,microbial biomass（C,N,P） and bulk density（BD） closely related to comprehensive fertility,so they could be used as the key evaluating indicators of the soil fertility.The soil fertility degradation trend was basically consistent with the succession of RD,but regional differences and human intervention could have a huge impact on soil fertility of RD.