The Seasonal Variation And Comprehensive Evalution Of Soil Fertility Of First-tier Costal Protection Forests In Shanghai

This article studies four first-tier costal protection forests, including of Ascendensmucronatum, Metasequoia glyptostroboides, Ligustrum lucidum, Fraxinus pennsylvanica andbeach land(CK) with similar site condition by analyzing the soil physical and chemical propertiesand enzymatic activity in Nanhui district, Shanghai City.The results are as follows:1. The differences of soil physical properties of four forests were not too obvious. The soilbelongs to alkaline clayey soil. There was a significant negative correlation between the soil bulkdensity and the water content and total porosity. Soil physical properties of different soil layersdiffer significantly or very significantly.2. The analysis of Soil N, P and K showed that the average content of total N and total Phave a trend of Ascendens mucronatum＞Metasequoia glyptostroboides＞Ligustrum lucidum＞Fraxinus pennsylvanica＞beach land. The content of available K was the highest in theMetasequoia glyptostroboides and lowest in the Ligustrum lucidum, but the differences of threeelements didn't reach significance level in the four forestland. Content of rapidly available K wasthe highest, and available P was the lowest. The differences of available N,P reached significancelevel in the different forestland. Besides, two forms of N,P,K had the significant differences in thedifferent soil layers.3. Through single-correlation analysis,the correlations of many soil indexes were significant.Canonical correlation analysis showed that total N, available P and available N played leadingroles in soil nutrient comprehensive factor and urease and alkaline phosphatase in soil enzymaticactivity comprehensive factor.4. The soil nutrient and enzymatic activity showed specific regularity of seasonalvariation.Content of soil available N, available P and rapidly available K presented the rule ofsummer＞spring＞autumn, but the difference significance of various elements was different.5. Adopting the theory of Grey Relation Degree and Improved Analytic Hierarchy Processto evaluate soil quality, and the result was in favor of the latter. The comprehensive evaluationvalues of soil fertility quality rom high to low in order was Ascendens mucronatum (0.672)＞Metasequoia glyptostroboides (0.616)＞Ligustrum lucidum (0.483)＞Fraxinus pennsylvanica(0.434)＞beach land(0.278)...