喀斯特山区不同石漠化等级下土壤养分贮量与价值评估——以乌箐、偏岩等岩溶小流域为例

Assessment on the storage and value of soil nutrient under different grade of rocky desert in karst hilly region: A case study in small karst watersheds Wuqing and Pianyan of Guizhou Province

为探讨石漠化等级对土壤养分贮量与经济价值的影响,以贵州省金沙县喀斯特山区无石漠化农耕地(Ⅰ)为对照,在研究潜在(Ⅱ)、轻度(Ⅲ)、中度(Ⅳ)、重度(Ⅴ)石漠化土壤养分含量变化的基础上,采用土壤养分库贮量计算方法和价值替代法计算评估了不同石漠化等级下土壤养分贮量及其潜在价值。结果表明:(1)0～40cm土层有机质、全氮、水解氮、全磷、有效磷、全钾、速效钾含量分别为32.31～104.12g/kg、1.35～2.87g/kg、76.90～124.00mg/kg、0.49～1.12g/kg、1.03～10.71mg/kg,12.25～26.22g/kg、114.35～245.35mg/kg;(2)土壤养分总贮量和有机质、全氮、全磷、全钾贮量依次为3.79～61.41t/hm2和2.55～48.56t/hm2、0.13～1.36t/hm2、0.04～0.52t/hm2、1.07～10.97t/hm2;(3)土壤养分总价值和有机质、全氮、全磷、全钾价值分别为0.86～9.80万元/hm2和0.08～1.55万元/hm2、0.29～3.08万元/hm2、0.04～0.53万元/hm2、0.45～4.64万元/hm2;(4)土壤养分贮量、价值均以Ⅰ最高,Ⅴ最低,随着石漠化程度加剧,土壤养分含量、贮量和价值均下降。

In order to discuss the impacts of different grades of rocky desert on soil nutrient storage and economic value,the soil nutrient storage and its potential value in different grades of rocky deserts are assessed by means of soil nutrient pool calculation method and value substitution method.The basis of the assessment in this paper is the studying on the variations of soil nutrient contents in rocky deserts with potential desertification（Ⅱ）,mild desertification（Ⅲ） and moderate desertification（Ⅳ） as well as severe desertification（Ⅴ） in comparison to the farmland without karst desertification（Ⅰ）.The results show that,firstly the contents of organic matter（OM）,total N（TN）,available N（AN）,total P（TP）,available P（AP）,total K（TK） and available K（AK） of soil in 0 to 40 cm depth is 32.31-10^4.12 g/kg,1.35-2.87 g/kg,76.90-124.00 mg/kg,0.49-1.12 g/kg,1.03-10.71 mg/kg,12.25-26.22 g/kg and 114.35-245.35 mg/kg respectively;secondly,the storages of total soil nutrients,OM,TN,TP and TK is 3.79-61.41 t/hm^2,2.55-48.56 t/hm^2,0.13-1.36 t/hm^2,0.04-0.52 t/hm^2 and 1.07-10.97 t/hm^2 respectively;thirdly,the values of total soil nutrients,OM,TN,TP and TK is 0.86-9.80×10^4 yuan/hm^2,0.08-1.55×10^4 yuan/hm^2,0.29-3.08×10^4 yuan/hm^2,0.04-0.53×10^4 yuan/hm^2 and 0.45-4.64×10^4 yuan/hm^2 respectively;fourthly,soil nutrient storage and value are the highest in grade Ⅰ and lowest in grade Ⅴ,and the content,storage and value of soil nutrient decrease with the aggravating of rocky desertification.