Research Of Distribution Of Soil Organic Nitrogen Component Of Apple-Pear Orchard In Yanbian Area

In order to evaluate the effects of apple-pear orchard soil depth and planting years on the contents of apple-pear orchard soil organic nitrogen, organic nitrogen forms in apple-pear orchard and wasteland soil were quantified using the method proposed by Bremner in1965. The results of the study can provide the important scientific basis for rational application of fertilizer in Yanbian apple-pear soil and scientific management of orchard in Yanbian area. The results indicated:in addition to the amino sugar-N, all the soil organic N components within the same soil layer in wasteland were more than those in apple-pear orchard soil, with layers depth increasing, the content of different organic nitrogen forms in apple-pear orchard soil and wasteland were decreased, the proportion of each organic N components within total hydrolysable N was different, and there is no obvious change rule with the increasing depth in the profiles. The same planting years, acid-hydrolysis organic N, ammonia nitrogen and amino sugar nitrogen components in the inside of tree-crown soil were more than those in outside of tree-crown soil, with planting years increasing, the content of amino sugar nitrogen and amino acid nitrogen in inside of tree-crown soil were increased, and when the planting years is40, the content of acid-hydrolysis organic N and ammonia nitrogen reached the peak value. The same soil depth and the same planting years soil in Yanbian area, ammonia nitrogen and amino acid nitrogen components is higher than other organic nitrogen forms components, but the amino sugar nitrogen component is the lowest.