Studies on response of maize to dissolved organic matter as influenced by fertilizers in different farmland soils using three-dimensional excitation-emission matrix spectroscopy.

摘要

Three-dimensional excitation-emission matrix fluorescence spectroscopy (3D-EEMS) was used to investigate the effects of fertilization treatment on the composition and related properties of dissolved organic matter (DOM) in corn fields that were treated with fertilization treatment for three years. The 3D-EEMS spectrogram of soil samples had three main peaks: peak-A, related to humic acid-like (HA-like) material at an Ex/Em of 310-330/395-420 nm; peak-B, related to UV fulvic acid-like (FA-like) material at an Ex/Em of 230-280/400-435 nm; and peak-E, related to simple aromatic proteins at an Ex/Em of 210-240/290-340 nm. In comparison with the 3D-EEMS spectrogram of the basic soil samples, that of the soil samples with fertilization treatment indicated that the intensities of peak-A and peak-B were reduced and the intensity of peak-E was increased in middle-yielding fields and low-yielding fields. Furthermore, the fertilization treatment enhanced crops on the use of soil organic matter and improved the ability of soil to provide continuous fertility. The fertilization treatment mainly increased the fertility of the deep soil layer and promoted the decomposition and utilization of soil DOM. By comparing the r(A,B) and f450/500 values, it was found that with fertilization treatment promoted the degree of maturity of high-yielding and middle-yielding fields and that it increased the terrigenous DOM of high-yielding fields and biological source DOM of middle-yielding and low-yielding fields. Peak-A and peak-B were significantly and positively correlated to the content of DOC, DON, DOP, microbial biomass carbon, microbial biomass nitrogen and corn yield. Soil fertility, microbial biomass and crop growth were found to be important factors that increased the fluorescence intensities of soil DOM.