长江经济带土壤质量评价及产地适宜性初步研究

开展土壤质量评价对科学划定永久基本农田及统筹优化农业生产布局具有重要指导意义。本文采用内梅罗综合污染指数法、分级法、累积频率法和综合判定法,参照《土壤环境质量农用地土壤污染风险管控标准》(试行)(GB 15618—2018)和《绿色食品产地环境质量》(NY/T 391—2013),对长江经济带土壤重金属污染、酸碱度、有益元素丰缺和绿色农产品产地适宜性进行评价。研究区土壤质量总体良好,清洁土壤面积34.84万km²,其重金属含量继承了自然背景特征; 三级及以下土壤面积6.94万km²,呈斑块及星点状分布于赣东北、赣南、湖南长沙—郴州一带、沿江及贵阳、昆明等地,其重金属为自然富集或受矿业开发、煤炭和石油的燃烧及工业“三废”排放的影响。酸性土壤面积33.56万km²,分布于江西、湖南、宁波—台州沿海和金华衢州盆地,碱性土壤面积15.69万km²,分布于苏北平原、环洞庭湖、成都平原以及沿长江一线,其土壤酸碱度与土壤类型有关。土壤有益元素丰缺与第四系沉积物成土母质有关,土壤有益元素适量及以上区域面积34.44万km²,分布于四川阿坝、成都盆地、环洞庭湖、环鄱阳湖、安徽沿江、苏北沿海和杭嘉湖平原; 土壤有益元素缺乏区面积13.89万km²,分布于赣南、江淮、鄂东北以及云南玉溪等地。绿色农产品产地最适宜区、适宜区和不适宜区面积分别为22.49万km²、18.78万km²和18.28万km²。依据区内绿色农产品产地适宜性、土壤环境质量和立地条件划分出7片永久农田保护建议区。

Preliminary study on soil quality assessment and producing area suitability in Yangtze River Economic Zone

It is of great significance to carry out soil quality assessment for the delimiting of the permanent basic farmland and overall optimization of agricultural production layout. Nemerow comprehensive pollution index, grading, cumulative frequency and integrated decision method were adopted in this paper, and Risk Control Standard for Soil Contamination of Agricultural Land (GB 15618-2018 ) and Green Food- Environmental Quality for Production Area (NY/T391-2013) were chosen as reference. The heavy metals, pH values, beneficial elements abundance-deficiency and producing area suitability for green agricultural products were evaluated in Yangtze River Economic Zone. The land quality of the study area is generally good, and the clean land area is 348 400 km². The heavy metals content of the soil inherits the characteristics of natural background. The land area of and below the third stage is 69 400 km², distributed in star-shaped plaques in Northeast and South Jiangxi, Changsha-Chenzhou area of Hunan, along the river and Guiyang, Kunming and other places. Their heavy metals enrichment was caused by natural factors or mining development, combustion of coal and oil and industrial three wastes emission. Acidic soil area is 335 600 km², mainly distributed in Jiangxi, Hunan, Ningbo-Taizhou coastal region and Jinhua-Quzhou Basin. Alkaline soil area is 156 900 km², mainly distributed in North Jiangsu Plain, around Dongting Lake area, Chengdu Plain and the area along the Yangtze River. Soil acidity and alkalinity is related to soil type. Abundance-deficiency of beneficial elements in soils is related to the soil parent material of Quaternary sediments, and the moderate-high area of beneficial elements is 344 400 km², mainly distributed in Sichuan Aba, Chengdu Basin, around Dongting Lake, around Poyang Lake, Anhui Province along Yangtze River, North Jiangsu coastal region and Hangzhou-Jiaxin-Huzhou Plain. Deficiency area of beneficial elements is 138 900 km², distributed in South Jiangxi, Jianghuai, Northeast Hubei and Yunnan Yuxi and other places. The most suitable area, suitable area and unsuitable area for green agricultural products are about 224 900 km², 187 800 km² and 182 800 km² respectively. According to the producing area suitability for green agricultural products, cultivated land quality and site condition in the region, 7 pieces of permanent farmland protection proposal areas are established.