近15年温州市主要农用地土壤酸碱度变化趋势及成因探讨

Study on the changing trend and causes of soil pH value of main agricultural land in Wenzhou in recent 15 years

土壤酸化已成为制约我国耕地质量主要因子之一,影响到我国粮食安全,将其纳入动态监管,加强变化趋势综合研究任重道远。基于浙江省温州市2004年和2019年两期主要农用地表层土壤数据,采用传统统计学、地统计学和栅格运算等方法研究了温州市主要农用地土壤pH变化趋势,并对其驱动因子进行分析。结果表明,近15年内温州市主要农用地土壤pH均值由6.03降为5.58,下降了0.45个单位,年平均降低0.03个单位。土壤酸碱度变化因成土母质、土壤类型和土地利用类型而异,其中4种成土母质土壤pH全部下降,下降幅度依次为滨海相沉积物>河湖相沉积物>火成岩类风化物>沉积岩类风化物;5种土壤类型中水稻土、滨海盐土和红壤下降较为明显,分别下降了0.53、0.49和0.42个单位,粗骨土下降了0.19个单位,潮土平均上升了0.20个单位;5种土地利用类型土壤中茶园土壤pH下降了1.17个单位,水田土壤下降了0.61个单位,旱地、果园和林地土壤下降程度基本一致。近15年温州市主要农用地酸性土壤面积大幅增加,土壤酸化问题日趋严重。土壤类型、酸沉降、化学肥料以及海水倒灌是影响近15年温州市主要农用地土壤pH变化的主要因素。

Soil acidification has become one of the main factors restricting the quality of cultivated land in China,affecting the food security of our country,bringing it into dynamic supervision and strengthening the comprehensive research on the trend of change has a long way to go.Based on the topsoil data of main agricultural land in Wenzhou in 2004 and 2019,the change trend of soil pH was studied by means of traditional statistics,geostatistics and grid operation,and its driving factors were analyzed.The results showed that the average soil pH value of main agricultural land in Wenzhou decreased from 6.03 to 5.58 in recent 15 years,decreased by 0.45 units,with an average annual decrease of 0.03 units.The change of soil pH varied with soil parent materials,soil types and land use types,which showed that the pH value of four kinds of soil parent materials all decreased,the descending amplitude was littoral sediments>fluvial and lacustrine sediments>igneous rock weathering material>sedimentary rock weathering material;Among the five soil types,paddy soil,coastal saline soil and red soil decreased significantly,by 0.53,0.49 and 0.42 units,respectively,the skeletal soil decreased by 0.19 units,while the fluvo-aquic soil pH increased 0.20 units on average;In the five land use types,the pH value of tea garden soil decreased by 1.17 units,and that of paddy field soil decreased by 0.61 units,the decline degree of dry land,orchard and woodland was basically the same.The acidic soil area of the main agricultural land in Wenzhou has increased greatly in the past 15 years,and the problem of soil acidification is becoming more and more serious.Soil type,acid deposition,chemical fertilizer and seawater reverse irrigation are the main influence factors of the soil pH value changes of main agricultural land in Wenzhou in recent 15 years.