城镇化对我国不同年代农田氮素循环的影响

Influence of urbanization on N cycle of farmland of various periods in China

利用调查数据、文献资料和统计数据,采用物质流分析的方法,就城镇化对全国不同年代农田氮素循环的影响进行了初步探讨。结果表明:在全国这个相对封闭的大系统中,城镇化率与农田养分循环各指标间都存在显著正相关关系,随着年代的增加,在城镇化发展的同时,单位面积化肥氮投入量越来越高,2005年是1980年的2.7倍左右;单位面积有机氮投入量2005年是1980年的2倍左右,单位面积总氮投入量2005年是1980年的2.5倍左右,同时土壤养分的盈余量越来越多,对环境的威胁越来越大。

This study preliminarily probed into some impacts of urbanization through survey data, literatures, statistical data and material flow analysis. The relationships between urbanization and regional nitrogen balance in agro-ecosystem were analyzed in light of survey on farmland of different periods in China. The results showed that in this relatively dose system of the whole country, there is a significantly positive correlation between urbanization rate and various indexes of farmland nutrient circulation; as time time passes and urbanization continues, use of fertilizer nitrogen per hector was becoming higher, roughly 2.7 times that of 1980 in 2005 ; use of organic nitrogen per unit area was about 2 times that of 1980 in 2005, use of total nitrogen 2.5 times that of 1980 in 2005 while the surplus amount of soil nutrient gradually increased.