| Saline land in Yulin is widely distributed,of many types,with complex causes and high salinization,which has a serious impact on the growth of local crops and restricts the development of agricultural production.To further understand and solve the problem of saline land in Yuyang District,this paper explores the effect of water-dry rotation on the trend of changes in soil physicochemical properties of saline land in Yuyang District based on a comprehensive investigation and experimental research,by conducting field experiments with maize and rice rotation from 2021 to 2022,and selecting eight plots for comparative experiments according to different rotation years to analyze the pH,conductivity,soil The purpose is to grasp the changes of water-dry rotation on the soil properties of saline soils,and to conduct experimental research on the application of sodium humate with different ratios of saline soils through indoor germination tests and potting tests from 2022 to 2023,to determine soil physical and chemical properties and grasp the changes of soil salinity and nutrients,so as to provide guidance for the management of saline farmland and crop production in Yuyang District.The main conclusions are as follows:(1)The pH and conductivity of the rice test site showed a decrease under different tillage measures,with pH decreasing by 2%-15% and conductivity decreasing by 52%-63%,while the maize test site showed an increasing trend;the soil organic matter and fast-acting phosphorus content of the rice test site showed a small increase,ranging from 0.5%-2% and 2%-6%,respectively;the soil alkaline decomposition nitrogen content was lower than the control;the maize The soil structure,soil color and root distribution of the soil profiles of paddy and dryland showed differences,among which the degree of alkalinization in the rice test site showed a decreasing trend and that in the maize test site showed an increasing trend.(2)Different salt concentrations had a certain effect on rice seed germination.The inhibition of rice seed germination increased with the increase of salt concentration,and the shoot length decreased by 23%-82% compared with CK.The salt stress on rice seedling growth increased significantly,and the root length and biomass of the plants decreased significantly.The salt stress effect was reduced by adding sodium humate,and the best growth,root length,shoot length,germination rate and germination potential were achieved with the concentration of 300 u mol/L sodium humate treatment.(3)As the proportion of saline soils increased,soil pH and conductivity increased,alkaline nitrogen content increased,organic matter,fast-acting phosphorus and fast-acting potassium showed an upward and then downward trend.Soil urease and catalase showed an overall trend of increasing and then decreasing,while sucrase did not show any obvious pattern.The pH and conductivity values of soil solution decreased after adding sodium humate to saline soils.Compared with the control,the increase of soil organic matter after the application of sodium humate ranged from 31% to 81%;the increase of alkaline nitrogen reached 30.5% to 67%;the increase of fast-acting phosphorus ranged from 5% to 43%,and the increase of fast-acting potassium ranged from 14% to 50%.The application of sodium humate had a greater effect on soil enzyme activity,inhibiting both soil urease and soil catalase,with enzyme activity decreasing,with soil urease decreasing by 17%-39% and catalase activity decreasing by 2%-12%;No significant change in soil sucrase activityIn conclusion,both water-dry rotation and sodium humate were able to change the physicochemical properties of the soil,improve soil nutrients and reduce salinity.The results of the study have theoretical and practical significance for improving saline land and arable land quality in Yuyang District. |
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