Research On The Changing Trend Of 25 Years Of Arable Soil Nutrients In Yushu City

Yushu city is the main grain producing areas in Jilin Province, the soil nutrient condition is representative in Jilin province. Yushu city soil reclamation time is short, the large area cultivated about three hundred years or so, before liberation only depends on the natural fertility, the implementation of management after the liberation of agricultural production have great development. In recent years, with the change of farmland tillage, soil fertility must also change. In order to find out the changes of soil fertility, and puts forward some related on the basis of improving soil fertility for the future research on how to maintain and change trend, namely the farmland nutrient cycling condition and soil nutrients on Yushu city study is to necessary. Therefore, this paper engages the existing data and the measured data, comparative analysis of Yushu city nearly 25(1984-2009) of soil nutrient variation trend of farmland soil organic matter, total nitrogen, total phosphorus, available nitrogen, available phosphorus and trace elements, it draws the following conclusions:(1) soil organic matter content in 25 years on average by 3.1 g/kg; The yushu city high organic matter content in the top layer of soil, mainly in yushu city city hair around the country, with more than 25 g/kg of area accounts for more than 30% of the whole study area;(2) reduce the soil total nitrogen content in 25 years average 0.09 g/kg;(3) the soil total phosphorus content in 25 years on average by 0.66 g/kg;(4) 18 township yushu city top layer soil alkali-hydrolysable nitrogen content is 138.18 mg/kg. High alkaline hydrolysis nitrogen content is mainly located in the township yushu city city hair around. Their spatial heterogeneity is the top layer of soil geography and mutual influence of the altitude;(5) the yushu city 19 villages and towns arable layer soil available p content was 26.82 mg/kg. At the same time that yushu city of jilin province in the top layer of soil available p content of variability;(6) effective copper content in soil increased by 0.83 mg/kg;(7) effective zinc content in soil increased by 0.59 mg/kg; Distribution presents obvious around the middle of the high low;(8) the content of soil effective iron 49.79 mg/kg;(9) soil effective manganese content by 21.02 mg/kg. Effective high manganese content, mainly in yushu city west, and the region of soil effective manganese content is relatively rich.