粤北岩溶山区石漠化过程中土壤养分变化研究

 为了探讨石漠化过程对土壤养分的影响,了解粤北岩溶山区石漠化过程中土壤养分的变化规律,选择岩背镇和江英镇为调查区,按照石漠化的不同程度设置样地,系统调查了轻度、中度、重度和极重度石漠化土地表层（0~20 cm）土壤养分的变化。结果表明,石漠化过程与土壤养分状况有密切关系,随着土地石漠化的发展,土壤有机质、全N以及速效N、速效P、速效K含量呈现出显著下降趋势（P<0.05）,土壤逐步贫瘠化。土壤养分含量的减少与石漠化过程形成正反馈关系,并具有退化方向的一致性和退化过程的同步性等特点。

Change of Soil Nutrient in Process of Rocky Desertification in Karst Mountainous Area of North Guangdong

For exploring the impacts of rocky desertification process on soil nutrient change and understanding the laws of soil nutrient variation in rocky desertification process in karst mountainous area of North Guangdong,a margin area of rocky desertification region in Yanbei town and Jiangying town was selected as study site.According to the different levels of rocky desertification: slight rocky desertification,moderate rocky desertification,severe rocky desertification,and very severe rocky desertification,the surface soil layer(0—20 cm) samples were investigated and analyzed.Results drawn from this case study are listed as follows: There is a close relationship between rocky desertification process and soil nutrient condition,and with the development of the rocky desertification,the contents of soil organic matter,total N,available N,available P and available K show a obviously decreasing trend(P<0.05).Simultaneously,soil became more and more infertile.The decrease of soil nutrient contents shows a relation of positive feedback with rocky desertification process,and there is consistency in the degradation direction and synchronism in the degradation process.