School of Geography and Resources Science, Neijiang Normal University
Supported by the National Innovation and Entrepreneurship Training Program for College Students (No. X2018015), the Key Project of Neijiang Normal University (No. 17CZ03) and the Project of Neijiang Normal University (No. 17JC25)
近年来紫色水稻土区农业种植结构发生很大变化，深刻影响了土壤钾素的赋存形态和动态平衡。厘清土地利用方式改变对紫色水稻土不同形态钾演变特征的影响，对紫色水稻土区钾肥管理和环境保护具有重要意义。运用时间序列方法，分析了紫色水稻土在撂荒、旱作和改为鱼塘后土壤不同形态钾的动态变化特征和影响因素。结果表明紫色水稻土利用方式改变后，土壤水溶性钾与土壤水分状况密切相关。撂荒和旱作均会降低土壤水溶性钾含量，改为鱼塘后能提升土壤水溶性钾含量。3种土地利用方式均能提升土壤交换性钾和非交换性钾含量，提升幅度和提升速率为旱作>撂荒>养鱼。紫色水稻土改为鱼塘5 a后或撂荒12 a后土壤不同形态钾之间可以达到大致的平衡，而旱作20 a后土壤不同形态钾之间仍未达到大致的平衡。紫色水稻土利用方式改变后土壤黏粒含量和黏粒矿物的动态变化与土壤中的钾平衡有关。土地利用方式改变导致的土壤有机质（SOM）损失可能会影响土壤钾的赋存形态和动态平衡，进而引起土壤黏粒的富集和黏粒矿物的变化，今后要加强这方面的研究。
【Objective】Significant changes have recently taken place in the agricultural planting structure of the purple paddy soil area. These changes have profoundly affected the form and dynamic balance of soil potassium. Thus, understanding the impact of land-use changes on the evolution characteristics of different forms of potassium in purple paddy soil is of great significance to regional potassium management and environmental protection. 【Method】In this paper, we analyzed the dynamic characteristics and influencing factors of different forms of potassium in the purple paddy soil after abandonment, dry farming and conversion to fish ponds, using the time series method. 【Result】The results showed that abandonment and dry farming reduced the water-soluble potassium content of purple paddy soil, and conversion to fish ponds increased the water-soluble potassium content of purple paddy soil. Abandonment, dry farming and conversion to fish ponds could all increase the exchangeable potassium and non-exchangeable potassium content of purple paddy soil. Both the increasing magnitude and rate are highest for dry farming, intermediate for abandonment, and smallest for fish farming. 【Conclusion】In the purple paddy soil, potassium in different forms reached a general balance after 5 years of fish farming or 12 years after abandonment. However, after 20 years of dry farming, the different forms of potassium in the soil did not reach a general balance. The results also showed that the release of mineral potassium in purple paddy soil was relatively fast in the natural state. After the land-use changes, there were complex connections between the occurrence and dynamic balance of purple paddy soil, the loss of soil organic matter, and the transformation of soil clay minerals, which needs further research.
LI Xiuzhi, HU Conyue, YANG Fan, HAN Guangzhong. Influence of Land Use Changes on Evolution of Different K Forms in Purple Paddy Soils[J]. Acta Pedologica Sinica, DOI:10.11766/trxb202106290334,[In Press]