Distribution of DOM in Soil Profiles Under Different Types of Organic Fertilizer During the Growth Period of Lettuce

The application of organic fertilizer is an effective way improve the quality and efficiency of crop production, Studying the distribution of dissolved organic matter (DOM) in soil profiles under the application of organic fertilizer from ifferent sources is helpful to optimize the utilization of organic fertilizer and further understand the environmental behavior of OM. This paper used 2D correlation spectroscopy (2D-COS) to study the effects of different organic fertilizers (pig manure. Chicken manure, sheep manure, cow manure, and biogas residue) on DOM distribution in the soil profile. The results showed that organic fertilizer return the field mainly affected the soil's relative content and composition of DOM. After applying different organic fertilizers, the relative content of DOM in soil was always higher than that in control (CK) treatment, and the Relative content of DOM in the 0 similar to 10 cm soil layer had the greatest effect, with an average increase of 14.67 g . kg(-1) Different ypes of organic fertilizer had a certain difference in the increase of profile DOM, among which chicken manure organic fertilizer had the greatest effect on the increase of profile DOM. increasing by 21.42%. The application of organic fertilizer mainly bereased the relative content of tyrosine like components (CA), and had the greatest impact on the relative content of Ct in the 10-20 cm soil layer. with average increase of 4. 12% in which sheep manure and biogas residue had the greatest impact. with an increase of 7.80% and 7.89%, respectively. 2D COS analysis showed that applying organic fertilizer from different ources greatly impacted dissolved microbial metabolites and protein-like components (295. 315 nm) CK and chicken manure #reatment mainly affected dissolved microbial metabolites, and other treatments first responded to protein like components. The Aumification index HIX. F-n (330) and F-n (280) decreased with the increase of soil depth. Still, the changes of HIX, F-n (330). and F-n (280) were different with different types of organic fertilizer. among which cow manure had the greatest effect on HIX and F-n (330), Sheep manure had the greatest effect F-n (280). The biological index beta : alpha increased with the increase of soil depth and the influence of biogas residue was the most significant, Still, the fluorescence index FI had Bo significant change.