江苏省农田氮素平衡的时空变化特征分析

SPATIO TEMPORAL VARIATION CHARACTERISTICS OF NITROGEN BANLANCE IN FARMLAND IN JIANGSU PROVINCE

关键词:  氮素盈余时空变化氮平衡模型农田江苏省

Key words:  nitrogen surplus  spatio temporal variation  nitrogen balance model  farmland  Jiangsu province

摘要:

［目的］探究江苏省农田氮素盈余状况的时空变化规律，并识别氮素污染的潜在风险区域。［方法］基于江苏省农业生产统计数据，运用氮平衡模型，分析全省农田氮盈余的时空变化特征。［结果］（1）1979—2015年江苏省农田氮盈余量从1979年的151万t上升至2015年的2967万t，总体经历相对平稳、持续上升到稳步下降的变化过程，由升到降的时间拐点在2003年。氮肥作为第一大氮输入源，所占比例始终介于60％～82％之间，对江苏农田氮素平衡起决定性作用； （2）2005—2015年苏北地区农田氮素大多呈高输入、高输出状态，苏南地区则有低输入、低输出的特征，氮肥依旧为各地第一大氮输入项，输入高值区分布在徐州、盐城； （3）2005—2015年江苏省农田氮盈余强度从13578kg/hm2 降低至6485kg/hm2，各地农田氮盈余强度普遍下降，但南北分化明显，位于江苏北部的徐州、宿迁和淮安，农田氮素盈余强度总体维持较高水平，苏南太湖流域地区、江苏沿江地区和沿海地区，氮素盈余强度相对较弱，且期间有继续下降倾向，镇江、泰州、扬州与南京，新近农田氮素甚至呈亏缺状态。［结论］基于上述测算结果，提出农田氮过剩污染风险区的农业生产调整对策思路。

Abstract:

To explore the spatio temporal variation of nitrogen surplus in farmland of Jiangsu, and identify potential risk areas of nitrogen pollution. Based on statistical data of agricultural production in Jiangsu province, the variation characteristics of nitrogen surplus were analyzed by using nitrogen balance model. The results showed that (1) The nitrogen surplus in farmland of Jiangsu rose from 151 000 tons in 1979 to 296 700 tons in 2015, and the total nitrogen surplus in farmland experienced a process of relatively stable, continuous rise and steady decline, and the turning point from the rise to the fall was in 2003. As the first major nitrogen input source, the proportion of nitrogen fertilizer was always between 60%~82%, which played a decisive role in nitrogen balance of farmland. (2) From 2005 to 2015, most of farmland nitrogen in Northern Jiangsu showed high input and high output, while Southern Jiangsu had the characteristics of low input and low output. Nitrogen fertilizer was still the largest nitrogen input item over the whole province, and the input high value area was distributed in Xuzhou and Yancheng. (3)During 2005 2015, the nitrogen surplus intensity of farmland decreased from 135.78kg·hm2 to 64.85kg·hm2, and all regions decreased generally, but the differentiation between the north and the south was obvious. Xuzhou, Suqian and Huaian in Northern Jiangsu , the nitrogen surplus intensity of farmland maintained a high level in general. In the Taihu Lake Basin, Jiangsu along the Yangtze River and coastal areas, the intensity of nitrogen surplus was relatively weak and tended to decline in the meantime, even in Zhenjiang, Taizhou, Yangzhou and Nanjing, nitrogen in farmland had been deficient in recent years. Based on the above calculation results, the countermeasures of agricultural production adjustment were proposed for the risk zone of nitrogen surplus pollution in farmland.