福建省耕地土壤pH空间分布及影响因素分析

为研究福建省耕地土壤酸化防控、耕地质量和产能提升的科学途径，以福建省耕地土壤为研究对象，采用地统计学与ArcGIS并结合随机森林模型，对福建省4 261个耕地表层土壤调查样点数据进行分析，探究福建省耕地土壤pH空间分布特征及主要驱动因子。结果表明，福建省耕地土壤pH自东南沿海至内陆山地地区呈逐渐降低趋势：全省耕地土壤pH为3.00～9.62，平均值为5.35，变异系数为14.95%,69.3%的耕地土壤pH小于5.5；南平市（5.09）、三明市（5.16）、龙岩市（5.21）、宁德市（5.22）及漳州市（5.42）70%以上的耕地土壤pH<5.5；而厦门市（5.58）、泉州市（5.90）、福州市（5.62）及莆田市（5.96）50%以上耕地土壤pH>5.5。海拔、降雨量、土壤有机质、土壤质地、土壤类型和作物类型显著影响土壤pH，土壤pH与海拔、降雨量和有机质呈显著负相关关系。砂土土壤pH为5.38，显著高于壤土（5.20）和粘土（5.14）；滨海盐土土壤pH为6.36，显著高于潮土、水稻土、砖红壤、紫色土、黄壤和红壤；黄壤和红壤土壤pH显著低于潮土和水稻土，潮土和水稻土土壤...

Spatial distribution of soil pH and the main driving factors in farmlands of Fujian Province

Aiming at alleviating soil acidification, improving soil quality and productivity of farmland in Fujian Province, this study chose the farmland of Fujian Province as the research object. The geo-statistics, ArcGIS and random forest modelling methods were used to analyze the 4 261 farmland surface soils pH and explore the spatial distribution of soil pH and main driving factors in Fujian Province. The results showed that the farmland soil pH in Fujian Province displayed a decreasing trend from the southeast coast to the inland mountainous areas. The range of soil pH was 3. 00 to 9. 62, and the average value and coefficient of variation were 5. 35 and 14. 95%, respectively. The soil pH of 69. 3% farmlands had soil pH lower than 5. 5. The soil pH in Nanping City, Sanming City, Longyan City, Ningde City and Zhangzhou City were 5. 09, 5. 16, 5. 21, 5. 22 and 5. 42. More than 70% of the farmland soil pH in above cities were lower than 5. 5. However, the soil pH of more than 50% of farmlands in Xiamen City(5. 58), Quanzhou City(5. 90), Fuzhou City(5. 62)and Putian City(5. 96)was higher than 5. 5. It was found that altitude, mean annual precipitation(MAP), soil organic matter(SOM), soil texture, soil type and crop type significantly affected soil pH. The soil pH had significant negative correlation with altitude, precipitation and soil organic matter. The pH of sandy soil was 5. 38, which was significantly higher than that of loamy(5. 20)and clay soil(5. 14). The pH of coastal saline soil was 6. 36, which was significantly higher than that of fluvo-aquic soil, paddy soil, lateritic red soil, purple soil, yellow soil and red soil. The pH of yellow soil and red soil were significantly lower than that of fluvo-aquic soil and paddy soil, and there was no significant difference between the fluvo-aquic soil and paddy soil. The soil pH of tea garden was 4. 67, which was significantly lower than that of orchard, vegetable, flue-cured tobacco, rice, tuber and oil crops. While the soil pH of oil crops, vegetable and tuber crops were significantly higher than that of rice, flue-cured tobacco and orchards, there was no significant difference in soil pH among rice and flue-cured tobacco. Random forest model analysis showed that soil organic matter and altitude were the most important factors driving the change of soil pH, followed by precipitation and crop types. Overall, nearly 70% of the farmland soils in Fujian Province were at the acid or strong acid level. The agricultural measures such as integrated nutrient management and additional application of alkaline materials are recommended to improve soil pH and promote the sustainable land use in this study.