摘要:
为掌握石漠化对岩溶地表土壤碳量的影响,选择粤北英德市岩背镇塘边村岩溶峰丛不同石漠化程度样地进行系统调查,采用单位面积土壤有机碳指标分析石漠化过程对土壤有机碳储量影响。结果表明:(1)极重度石漠化使土壤厚度、地表生物量显著减少,使岩石裸露率显著增加,但在潜在、轻度至中度石漠化中,差异不显著;(2)极重度石漠化土壤有机碳含量显著高于其他石漠化,中度石漠化土壤有机碳高于轻度石漠化,轻度高于潜在,但差异不显著;(3)10~20 cm 土层有机碳含量明显低于表层,岩石裸露及土壤主要在溶蚀缝隙中分布和发育是造成极重度和中度石漠化单位重量土壤有机碳增加的主要原因;(4)中度、轻度和潜在石漠化单位面积土壤有机碳分别是极重度的49.23倍、47.9倍和29.4倍;(5)岩石裸露率是影响岩溶地表生态的最主要因素,它和地表生物量之间存在极显著的负相关,与单位面积土壤有机碳总量呈显著的负相关关系,和土壤厚度也存在显著的负相关关系,此外,岩溶植物的高度适应性可以削弱石漠化的影响。
Abstract:
In order to analyze the effect of rocky desertification on the storage of soil organic carbon,sample plots with different degrees of rock desertification in a typical karst peak-cluster in the Tangbian village, Yanbei town,Yingde City,the north of Guangdong Province are selected in this paper,and a new index of unit area soil organic carbon is adopted in the analysis on the effect of rocky desertification process to the or-ganic carbon storage.The results show that:(1)The thickness of soil and standing biomass decreased sig-nificantly and the rock coverage increased significantly in intense rock desertification,but the difference are not significant between potential,slight and medium rock desertification in soil thickness,standing biomass and rock coverage.(2)Obviously,organic carbon content per unit of soil weigh is highest in intense rock de-sertification plots.It is higher in medium than in slight rock desertification plots,and it is higher in slight than in potential desertification plots,but the difference is not significant between medium,slight and poten-tial rock desertification.(3)The soil organic carbon content in 10 -20 cm soil depth is lower than that in 0-10 cm.Water and soil losing leads rocky coverage increase and only a little soil remain in the fissure of rock,those micro-negative relief can capture organic matter,that may be the major cause for the increase of soil organic carbon in intense and medium rock desertification.(4)The soil organic carbon content per unit area of in medium,slight and potential rock desertification is 49.23,47.9 and 29.4 times of that in intense rock desertification.(5 )The rock coverage is the main factor that impacting the karst ecological system. There is significant negative correlation between the rock coverage and the ground biomass,between the rock coverage and unit area of soil organic carbon,and between the rock coverage and thickness of soil.Highly a-daptive plants in karst area can weaken the effects on soil organic carbon by rock desertification.
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