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Poor soil fertility conditions limit agricultural production and development in saline-alkali areas. At the same time, in order to solve the problem of environmental pollution caused by agricultural wastes, agricultural wastes are used for organic fertilization of saline-alkali soils. In this study, the amount and structure of soil dissolved organic carbon after the application of different organic wastes was assessed. The results showed that the content of dissolved organic carbon in each component increased significantly (p <.05), while treatment GS recorded the highest content of dissolved organic carbon in each organic carbon component. The UV-visible spectrum of soil dissolved organic carbon recorded different results after the application of organic materials. For water-soluble organic carbon (WSOC), treatment CS was most effective in increasing the molecular weight of soil WSOC while treatment GS was most beneficial in improving the hydrophobicity and aromaticity of soil WSOC. For thermal hydrolyzed organic carbon (THOC), treatment GS was most effective for increasing the molecular weight and hydrophobicity, while treatment SM was most beneficial for increasing aromaticity. For hydrochloric acid and hydrolyzed organic carbon (HHOC), treatment SM was most effective in increasing molecular weight, while treatment FG and GS were most beneficial in improving the hydrophobicity and aromaticity of HHOC. For Alkali hydrolysis of organic carbon (AHOC), treatment GS was most beneficial for increasing the molecular weight, aromaticity, and hydrophobicity of AHOC. Amongst all the treatments the organic material treatments increased the aromaticity, hydrophobicity, molecular weight, and humification degree of soil soluble organic carbon compared with CK. [ABSTRACT FROM AUTHOR]

Soil available nutrients and soil salt ions are considered to play a significant role in soil fertility. A two-year field experiment was conducted to investigate the effects of different agricultural organic wastes on soil available nutrients and soil ions in a primary saline soil, located in the west of Jilin Province, China. The treatments were granular corn straw (GS), coarse corn straw (CS), sheep manure (SM), fodder grass (FG), and control (CK). The results showed that agricultural organic wastes effectively decreased soil pH by 1.28%-3.83%. The application of agricultural organic wastes also improved soil available nutrients, of which the available nitrogen (AN) increased by 23.64%-32.54%, the available phosphorus (AP) increased by 16% −19.93%, and the available potassium (AK) increased by 2.78% – 8.42%. In contrast, the content of soil salt ions decreased significantly with the exception of potassium ions. Linear dependence suggests that, with the decrease of soil pH, the soil available nutrient content was higher. From the correlation analysis, the relationship between other salt ions and soil available nutrients showed an extremely significant negative correlation with the exception of potassium (K+). The redundancy analysis (RDA) showed that calcium (Ca2+) and potassium (K+) are the main factor affecting soil available nutrient content in 2a (about 12 months after organic wastes were applied) and 3a (about 24 months after organic wastes were applied), respectively. In conclusion, treatment GS is recommended for improving soil available nutrients and decreasing the pH and content of soil salt ions in primary saline-alkali soils. CK: control without orgaanic material; GS: granular corn straw; CS: coarse corn straw; SM: sheep manure; FG: fodder grass; AN: available nitrogen; AP: available phosphorus; AK: available potassium; RDA: redundancy analysis; 1a: before the application of organic wastes; 2a: about 12 months after organic wastes were applied (first year); 3a: about 24 months after organic wastes were applied (second year). [ABSTRACT FROM AUTHOR]