基于 GIS技术的南方水土流失区耕地土壤养分丰缺分区

摘要

准确了解水土流失区耕地土壤养分丰缺空间分布对于开展精准施肥和水土保持工作具有重要意义。研究以典型南方红壤水土流失区福建省长汀县为例，利用近年耕地地力和水土流失现状调查资料，借助GIS与数学模型，对水土流失预防区和治理区耕地土壤养分空间丰缺状况及其差异进行了研究。结果表明：水土流失预防区耕地土壤有效磷、交换性钙、有效锌含量全部处于丰富水平，碱解氮、速效钾、交换性镁、有效硫含量处于丰富、中等水平耕地面积均超过预防区总面积70％；而水土流失治理区除了有效磷、交换性钙、有效锌外，其他养分元素均处于中等或缺乏水平；长汀县水土流失预防区耕地土壤各养分含量均高于治理区，其中交换性钙和镁高出100％以上，有效硼和速效钾高出50％以上，其余养分一般高出10％。这说明：长汀县耕地土壤的养分含量和养分丰缺空间分布的差异与水土流失程度具有相关性，水土流失程度越严重，耕地土壤养分含量越低，养分丰缺空间分布差异越大，诱发水土流失的自然条件和人类活动影响是导致这一差异的原因。探究耕地土壤养分的丰缺状况及其空间分布差异，对耕地地力的提升和水土保持工作的开展具有重要意义。%Understanding the soil nutrient abundant and deficient spatial distribution in the soil erosion ar -ea of cultivated land has great significance to carry out precise fertilization and soil and water conservation work.Taking Changting County of Fujian Province as a typical example of the red-soil erosion area in Southern China ,based on the survey data of cultivated land capability and the current condition of soil erosion in recent years,using GIS and integrated mathematic models ,the spatial soil nutrient abundant and deficient condition and differences between the soil erosion prevention and management were explored .The results showed that in the soil erosion prevention area ,available phosphorus ,exchangeable calcium and available zinc in the cultivat-ed land were all at the rich level ,alkali-hydrolyzable nitrogen ,quick-acting potassium ,exchangeable magnesi-um ,and available sulphur at the rich or medium levels ,and the cultivated land occupied more than 70%of the soil erosion prevention area .In the soil erosion management area ,except for available phosphorus ,exchangeable magnesium and available zinc ,other soil nutrient elements were all at the medium level or deficient level .In gen-eral ,the amount of soil nutrients in the soil erosion prevention area were higher than that in the soil erosion man -agement area in Changting County ,exchangeable calcium and magnesium were more than 100%higher ,available boron and quick-acting potassium were more than 50%higher ,and the other nutrients were at least 10%higher . The result shows that the soil nutrient content and the soil nutrient abundant and deficient spatial distribution are related with the degree of soil erosion ,the heavier the degree of soil erosion is ,the lower the amount of soil nutri-tion in the cultivated land is and the greater the difference of soil nutrient abundant and deficient spatial distri -bution is.The natural condition and the influence of human activities ,which induce soil erosion ,are the reasons for the difference .So to improve the soil fertility level is the key to soil and water conservation work .To explore the soil nutrient condition and the spatial distribution differences of soil nutrients has important significance to the promotion of cultivated land quality and soil and water conservation work .