集约农业利用下红壤地区土壤肥力与环境质量变化及调控——江西省南昌市郊区和余江县案例研究

CHANGES IN SOIL FERTILITY AND ENVIRONMENTAL QUALITY IN RED SOIL REGION UNDER INTENSIVE AGRICULTURAL USE AND THEIR CONTROL—A CASE STUDY OF THE SUBURBS OF NANCHANG CITY AND YUJIANG COUNTY IN JIANGXI PROVINCE

选择江西省南昌市郊区和余江县分别代表红壤地区集约化农业快速发展的大城市郊区和典型农区,研究集约农业利用下红壤地区土壤肥力与环境质量的变化特征与调控措施.结果表明,20多年来,以南昌市郊区为代表的城郊菜地的土壤有机质含量平均增加21.53%（一般农田的土壤有机质含量变化不大）,土壤速效磷含量增加13.15～18.86倍,土壤速效钾含量平均增加1.15～1.35倍;而土壤全氮含量增加不明显,土壤硝态氮的积累不多;以余江县为代表的传统农区,土壤酸化趋势明显,近90%的土壤有pH下降现象,平均下降达0.5个单位;同时部分农田土壤有一定程度的重金属污染.农业种植业结构调整、化肥用量的增加特别是磷钾肥的大量施用、以及畜禽粪肥的施用,是造成土壤养分富集和失衡、土壤酸化的重要原因.工业生产是造成农田土壤污染的主要原因.短期减量施肥、配合施用养分促进剂,以及通过施用缓释肥料提高肥料利用率,均可在一定程度上控制养分的过度富集与失衡; 适当施用石灰等碱性改良剂是防治土壤酸化的重要措施;而对于轻度污染土壤,可以通过施用化学改良剂（如石灰等）,或种植超积累植物而得到修复.

Suburbs of Nanchang City and Yujiang County in Jiangxi Province, a typical area with rapidly developing intensive agriculture in city suburbs and a typical one with intensive traditional agriculture, respectively, were selected in a red soil region of Jiangxi Province for study of effect of intensive agriculture on soil fertility and environmental quality and countermeasures. Results show that twenty years of vegetable cultivation increased soil organic matter by 21.53 %, readily available phosphorus by 13.15- 18.86 times,readily available potassium by 1.15 - 1.35 times,but did not increase much total soil nitrogen and nitrate nitrogen in the suburbs of Nanchang. In Yujiang County, the trend of soil acidification was obvious, with 90 % of the soil falling in pH by 0.5 unit, meanwhile some farmlands were polluted by heavy metals to a certain extent., Readjustment of the agricultural structure, increased application of chemical fertilizer, P and K fertilizers in particular, and application of barnyard manure were found to be the major factors leading to soil nutrient enrichment/unbalance and soil acidification, and industrial production the main source of soil pollution. Reducing fertilizer input for a short term, using nutrient accelerant and applying slow-release fertiliz- er are positive measures to improve utilization efficiency of fertilizer, control excessive enrichment or unbalance of soil nutrients to some extent. Proper application of lime or other alkaline soil amendment is a major practice to prevent soil acidification. For slightly polluted soil, application of chemical ameliorator and cultivation of super-accumulating plants can be used to remedy the soils.