The Effect Mechanism of Fertilization Measures on the Three-dimensional Fluorescence Characteristics of Soil DOM Components

摘要

The composition of soil dissolved organic matter (DOM) can reflect the soil maturity and fertilizer supply capacity. Fertilization is an important management strategy to regulate soil DOM transformation by regulating fertility, crop growth, microbial biomass and enzyme activity. However, there are few studies on the effect mechanism of fertilization to soil microecology. Here, the data from a four-year fertilization experiment in Liaohe irrigation area of China was used to evaluate and quantify the biological and nutrient effect mechanism of fertilization on the three-dimensional fluorescence characteristics of DOM components by the three-dimensional fluorescence spectral area volume integral analysis method (EEM-FRI). The results showed that the combined application of organic and inorganic fertilizers had increased the proportion of soil humic acids and could affect the DOM contents in the soil depth. The single application of organic fertilizer had reduced the proportion of fulvic acids. The proportion of protein-like components was increased with the application of phosphate fertilizer. The single application of nitrogen fertilizer increased the proportion of microbial metabolites. The proportion of humic acids was decreased and the proportion of small molecule DOM was increased in the soil of planting spring maize and applying fertilizer. The planting of spring maize could increase the exogenous input and the terrigenous characteristics of soil DOM. The organic fertilizer could increase soil microbial source DOM. Fertilization measures had affected microbial biomass, enzyme activity and spring maize yield, regulated the degradation of DOM and affected the characteristics of DOM components. The yield of spring maize was negatively correlated with humic acids components and positively correlated with fulvic acids components. The characteristics of DOM components were affected by their sources, degradation of soil enzymes and crop growth. Fertilization measures had affected soil DOM components by supplying DOC, affecting microbial enzyme activities and regulating the growth of spring maize. Fertilization had mainly affected DOM components in soil layer of 10-20 cm. Mixed fertilization had affected soil DOM in deep layer (20-40 cm). Combined application of organic and inorganic fertilizers had increased the proportion of soil DOM, application of inorganic fertilizer, especially nitrogen fertilizer alone significantly reduced of fulvic acids component in DOM, application of N, P, K was beneficial to increase the proportion of microbial metabolites in DOM. The proportion of fulvic acids components in soil DOM could be used to characterize soil fertility and microbial activity, and its proportion was a key factor to affect crop yield.