Title: Change of Non-exchangeable Ammonium Nitrogen in the Process of Organic Nitrogen Mineralization of Typical Soils on Loess Plateau
Abstract: In order to investigate the content change of non-exchangeable ammonium nitrogen during the process of soil organic nitrogen mineralization,the typical soils collected from north to south on Loess Plateau were chosen as the material,and the Bremner incubation method was conducted and the soils were incubated for 60 d.The results showed that the contents of non-exchangeable NH4+-N increased with increasing the incubation time.The amount increased for non-exchangeable NH4+-N existed significant difference(P=0.022 9) among the different soil types after the 20d of incubation,however, it was not significantly different when incubation at 40 d(P=0.1379) and 60 d(P=0.115 9).The increased amount of non-exchangeable NH4+-N during the incubation indicated as the following tendency,namely,Eum-Orthic Anthrosols Los-Orthic Entisols Hap-Ustic Isohumisols Ust-Sandiic Entisols.Organic material influenced significantly the increased amount of non-exchangeable NH4+-N(P was 0.0002,0.0004 and 0.0003 when incubated at 20 d,50 d and 60 d,respectively).NH4+-N increased remarkably when Stipa bungeana and Medicago sativa were added compared with no addition.The contents of non-exchangeable NH4+-N increased significantly when added(NH4)2SO4 compared without addition at 20 d,40 d and 60d of incubation and P was 0.0037,0.0033 and 0.0027,respectively.It was the result that the NH4+-N from(NH4)2SO4 was fixed within the soil.The increased amount of non-exchangeable NH4+-N increased significantly for different soils,on which different vegetation types grew before the collection of soil samples,when incubated at 20 d(P=0.043 4),but not significantly at 40 d and 60d(P=0.7378 and 0.5375).The increased amount of non-exchangeable NH4+-N in the soil,on which crop straw and nitrogen fertilizer had been incorporated for a long-term period,was larger than that of no addition,but it was not significantly different among these two fertilization models.Soil clay,total N and organic matter were positively correlated remarkably with the contents of non-exchangeable NH4+-N,the increased amount of non-exchangeable NH4+-N had no correlation with soil clay,whereas it had significantly positive correlation with total N and organic matter.
Publication Year: 2007
Publication Date: 2007-01-01
Language: en
Type: article
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