Effects Of Fertilization Methods And Freezing-thawing On Organic Nitrogen Components Of Paddy Soil In Yanbian Area

Adopting soil organic nitrogen classification method presented by Bremner in 1965, researched the influences of different fertilization methods and Freezing-thawing action on the distribution of the organic nitrogen components of paddy soil in Yanbian area. In order to research paddy soil nitrogen cycle of the Yanbian region and provide a scientific basis for reasonable fertilization. The results showed that:Combined applications of organic and inorganic fertilizer was beneficial for improving ammonia nitrogen, amino acid nitrogen, acid-hydrolyzable unknown nitrogen. Single organic fertilizer was beneficial for improving total acid hydrolysable nitrogen mainly by improving ammonia nitrogen, amino acid nitrogen, acid-hydrolyzable unknown nitrogen. Inorganic fertilizer leads to the unhydrolysable nitrogen accumulations; Single organic fertilizer was beneficial for improving the ratio of amino acid nitrogen, ammonia sugar nitrogen of total nitrogen and reducing the ratio of non-hydrolysable nitrogen acid unknown nitrogen. The contents of soil organic nitrogen was reduced gradually with the decrease of soil layers.Most of soil microaggregate were 1 to 0.25mm,0.05 to 0.01mm and 0.01 to 0.002mm. There is a big correlation between organic nitrogen components and soil microaggregate. In 0 to 10cm soil, acid-hydrolyzable unknown nitrogen was mainly hosted in 0.05 to 0.01mm microaggregate, amino acid nitrogen was mainly hosted in 0.1 to 0.05mm microaggregate. In 10 to 20cm soil, Both amino acid nitrogen and ammonia sugar nitrogen were mainly hosted in 0.1 to 0.05mm microaggregate and 0.25 to 0.1mm microaggregate, secondly it was hosted in<0.002mm microaggregate. Acid unknown nitrogen and non-hydrolysable nitrogen were mainly hosted in 0.1 to 0.05mm microaggregate.Total acid hydrolysable nitrogen under single organic fertilizer and combined applications of organic and inorganic fertilizer had a trend of decrease after freeze-thaw action in Kaishan area. Five months of freezing and thawing process was benefit for accumulating total acid hydrolysable nitrogen in inorganic fertilizer soil and Liangshui town. A long time of freeze-thaw action (more than months), will make acidolysis soil total nitrogen loss. The biggest contribution to total nitrogen acid solution were ammonia nitrogen and amino acid nitrogen and amino sugar nitrogen. The regularity of non-hydrolysable nitrogen was in contrast with total acid hydrolysable nitrogen.