| In this study, the method of field investigation, sampling and laboratory analysis of Yijun County 10 towns 46 villages walnut woodland conducted a detailed investigation, sampling, has set up a representative sampling point 139.The measurement indexes are as follows: pH, SOM, TN, AN, TP, AP, TK and AK, and using the Nemerow index method, the Fuzzy mathematics method and Factor analysis method to comprehensively evaluate the soil fertility of this region. The research conclusions are as follows:1. The results showed that the type of Yijun County Cash forestland soil was weakly alkaline,the range of pH was between7.53 ~ 8.50, with an average of 7.96.SOM content was between 2.29 ~ 23.47 g?kg-1, with an average of 10.69 g?kg-1; TN content was between 0.13 ~ 3.12g?kg-1, with an average of 0.60 g?kg-1; TP content was between 0.24 ~ 2.01g?kg-1, with an average of 0.85 g?kg-1; AP content was between 0.53 ~ 77.15mg?kg-1, with an average of 5.6 mg?kg-1; SOM, TN, TP and AP are in low levels. AN was between 2.90 ~ 154.79mg?kg-1, with an average of 20.98mg?kg-1, which is a low level. TK content was between 13.03 ~ 20.39 g?kg-1, with an average of 15.76 g?kg-1; AK content was between 66.68 ~ 501.99mg?kg-1, with an average of 115.04 mg?kg-1; TK and AK are at high levels. After correlation analysis shows that there are different degrees of correlation between soil nutrients.2. Using the modified Nemerow index method evaluate soil fertility in the region shows that yao sheng town and peng town comprehensive health fertility coefficient were 0.89 and 0.90, belong to poor levels; wuli town, leiyuan town, chengguan town, xicun town, qipan town, yunmeng town, taian town and kuquan town comprehensive health fertility coefficient were between 0.96 to 1.27, belong to the general level. Using Fuzzy mathematics method to comprehensive evaluate of soil fertility Yijun county, the order of fertility level is wuli town>taian town>qipan town>chengguan town>xicun town>yunmeng town>leiyuan town>kuquan town>peng town>yaosheng town. Using Factor analysis combined with Principal Component analysis to integrated soil fertility of Yijun County concluded that: qipan town>kuquan town>chengguan town>taian town>yunmeng town>leiyuan town>wuli town>peng town>xicun town>yaosheng town; combineing Variance maximum rotation method for the factor loading matrix analysis, the first principal component and the third principal component factor are available factors, the second principal component and the fourth principal components factor are the whole volume factors.3. Yijun is belong to the loess plateau hilly-gully region, through the soil fertility evaluation has found that the fertility levels was low, duing to the soil parent material, climatic conditions, and the impact of crop cultivation methods, fertilization and artificial management level, resulting in the region’s soil is alkaline and low fertility. Although K content in soil can meet economic forest K serves, P content, N content and SOM content are low, this phenomenon indicats that lack of nutrient supply and poor fertility levels. Over all, the soil AP, AN and TN content can not meet the normal growth of the crop in this region, so not only to impose much N fertilizer, P fertilizer and manure in production management in the future, in order to increase soil N and P content and improve soil productivity; and to impose appropriate soil structural modifier to make soil neutral, we should appropriatly use organic manure and other acidic conditioners such as gypsum; At the same time, take the use of natural groundcover such as leaves, straw and so on. It can improve soil physical and chemical properties, but also to save and fix nitrogen nutrient and increase the content of humic substances in soil, and promote recycling waste farmland, so as to achieve the purpose of improving soil physical and chemical properties and improving soil fertility. |
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