[Effects of Organic Materials Applied to Saline Soil on Crop Growth and Soil Saline-alkali Index]

To provide a theoretical basis for the scientific application of organic materials in salinized soil and the improvement of soil quality and to explore the response phenotype of an organic material-salinized soil-plant system, the salinized soil in Xinjiang was considered as the research object, and cotton, rape, and oil sunflower were considered as the test crops. Six treatments, including the control group, microbial agent, humic acid, organic fertilizer, biochar, and straw, were set up for indoor culture experiments. The effects of different organic materials on the growth of cotton, oil sunflower, and rape crops and soil saline-alkali indexes under moderate salinization soil conditions were analyzed, and the combinations with certain improvement effects were screened out. This provided a certain experimental basis for the application and promotion of organic materials in Xinjiang. The results showed that, compared with that under the control treatment, the application of the microbial inoculant, organic fertilizer, and biochar had a significant effect on crop growth. At 60 d of emergence, the dry weight of cotton after the application of the microbial inoculant, organic fertilizer, and biochar increased by 41%, 43%, and 25%, respectively. The dry weight of oil sunflower increased by 5%, 13%, and 27%, respectively. The dry weight of rape increased by 113%, 104%, and 83%, respectively. After the application of organic fertilizer and biochar, the emergence rate of cotton and rape increased by 14.3% and 10.2%, respectively, and 26.50% and 20.82%, respectively. Taking the results of the soil salt-alkali index analysis at 60 d after seedling emergence as an example, the application of the microbial agent and straw had no significant effect on the total amount of water-soluble salt in the soil, whereas the application of humic acid, organic fertilizer, and biochar increased the total amount of water-soluble salt in the soil. The application of the microbial agent and straw could reduce soil pH, and the application of humic acid and biochar could increase soil pH. Soil electrical conductivity of all organic materials increased and humic acid treatment increased the most significantly. The effect of the microbial agent and straw treatment on soil alkalinity was the best, whereas the other treatments showed no significant difference. Straw could reduce soil sodium adsorption ratio, and humic acid and organic fertilizer could increase the soil sodium adsorption ratio. In summary, it is recommended to apply microbial agents, organic fertilizers, and biochar to saline soil for the purpose of promoting crop growth, and to apply a microbial agent and straw to saline soil for the purpose of improving soil quality.