Edaphon Faunas and Their Implications in Salinized Soil in the Ningxia Yellow River Irrigated Area

In order to know the dynamic change of soil edaphon faunas and the effect of soil chemical properties on edaphon in salinized soil at different degradation degrees,the distribution and seasonal dynamic change of edaphon,soil chemical properties,nutrient content and the correlation between edaphon and soil properties at different salinization levels in Huinong,Ningxia Hui Autonomous Region were studied using the plate dilution method and the conventional measurement of soil chemical properties.The results showed that,in the region with salinized soil,the pH value and basicity of slightly-salinized soil was the highest with the increase of soil salinization level,and they were higher in soil layer of 20-40 cm in depth than in soil layer of 0-20 cm.Soil nutrient content,bacteria,fungi and actinomycetes were all in a decrease trend with the severity increase of soil salinization,they were in an order of slightly-salinized soilmoderately-salinized soilseverely-salinized soil,and they were significantly higher in soil layer of 0-20 cm than in soil layer of 20-40 cm.Temporally,the number of bacteria,fungi and actinomycetes was in an order of JuneAugustSeptember.There was a significant correlation between edaphon faunas and soil nutrient content.There were the significant or highly significant positive correlations among the numbers of bacteria,fungi and actinomycetes and the contents of soil organic matter,total nitrogen,total phosphorus,alkali-hydrolyzable nitrogen,available phosphorus and available potassium(P0.05 or P0.01) except the situation with the total potassium content.Therefore,the values of soil edaphon faunas can be regarded as the biological indexes to evaluate soil improvement level and evolution of soil salinization.