Authors: Jiangpei Han Jiachun Shi Lingzao Zeng Jianming Xu Laosheng Wu
Publish Date: 2014/09/18
Volume: 22, Issue: 4, Pages: 2976-2986
Abstract
A greenhouse pot experiment was conducted to study the effects of conventional nitrogen fertilization on soil acidity and salinity Three N rates urea N0 0 kg N ha−1 N1 600 kg N ha−1 and N2 1200 kg N ha−1 were applied in five soils with different greenhouse cultivation years to evaluate soil acidification and salinization rate induced by nitrogen fertilizer in lettuce production Both soil acidity and salinity increased significantly as N input increased after one season with pH decrease ranging from 045 to 106 units and electrolytic conductivity increase from 024 to 068 mS cm−1 An estimated 092 mol H+ was produced for 1 mol NO2 − + NO3 −N accumulation in soil The proton loading from nitrification was 143–273 and 121–582 kmol H+ ha−1 in the center of Shandong Province under N1 and N2 rate respectively However the proton loading from the uptake of excess bases by lettuces was only 03–45 of that from nitrification Moreover the release of protons induced the direct release of base cations and accelerated soil salinization The increase of soil acidity and salinity was attributed to the nitrification of excess N fertilizer Compared to the proton loading by lettuce nitrification contributed more to soil acidification in greenhouse soilsThis work was jointly supported by National Hightech RD Program of China 863 Program 2012AA062603 the National Basic Research Program of China 2011CB100502 the Key SQT Innovation Team of Zhejiang Province for AgroProducts Standards and Testing Technology 2010R50028 the Zhejiang Provincial Natural Science Foundation of China LY13D010001 and the Fundamental Research Funds for the China Central Universities
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