Study On The Improvement Effect Of Different Rotation Modes On Soda Salinization Farmland In Xiliaohe Plain

The factors of soil degradation and sustainable productivity decline of Xiliaohe Plain were the high degree of soil salinization,poor soil physical and chemical properties,single crop planting pattern and frequent continuous cropping.How to adjust and optimize crop planting patterns to achieve efficient utilization of salinized land has become one of the hotspots of agricultural research.effects of five different crop rotation methods on soil physical and chemical properties and salinity characteristics and nutrient content and the economic benefits were studied.The best suitable rotation method for soda saline-alkali cultivated land in the Xiliaohe area of Inner Mongolia was screened,which provided theoretical support and scientific basis for the improvement and rational utilization of saline-alkali cultivated land in this area,as well as a reasonable crop rotation model.The results were as follows:（1）The soil physical properties were improved by crop rotation:the soil bulk density of the 0-40 cm soil layer was decreased by 4.63%-8.63%.and the total soil porosity was increased by 8.49%-14.90%under the treatment of Soybean-Silage Corn Rotation.the maximum water holding capacity of the 0-20 cm soil layer was increased by15.79%～28.70%,the minimum water holding capacity of the 0-5 cm soil layer was increased by 46.68%;the capillary water holding capacity of the Chaomu No.1-Gaodan grass rotation on the 0-20 cm soil layer was increased by 27.37%～33.00%.The minimum water holding capacity of the 5-10cm soil layer was increased by 49.94%.（2）The spatial distribution of soil salinity was affected by crop rotation:soil p H of0-40 cm soil layer was decreased by 2.12%-4.37%in treatment of Chaomu No.1-Gaodan grass rotation.Soil alkalinity of 0-40 cm soil layer was decreased by 9.42%～49.20%in treatment of soybean-silage corn rotation.The total soil salt in the 0-40 cm soil layer was decreased by 13.83%～50.90%in different rotation treatments.Among them,the Chaomu No.1-Gaodan grass rotation had the most significant effect on soil desalination efficiency,which was 14.07%-44.95%lower than the control.The contents of Cl^-,SO₄^2-,Mg²⁺,and Na⁺in 0-40cm soil layer of the Chaomu No.1-Gaodan grass rotation were significantly decreased 58.33%～74.08%and70.07%～90.31%and 60.60%～76.60%and 25.98%～53.98%respectively compared to the control.The content of HCO3-showed an upward trend,which was 11.21%～23.78%higher than the control.（3）The contents of soil nutrient were significantly increased in treatment of Soybean-silage corn rotation.Soil organic matter in 5-10 cm and 10-20 cm soil layers were increased by 8.24%and 6.06%respectively.The contents of total nitrogen and alkali-hydrolyzed nitrogen and available phosphorus and available potassium of 0-40 cm soil layers were increased by 43.41%-62.73%and 16.57%-37.30%and 19.71%-56.34%and 11.71%-19.38%respectively.（4）The soybean-silage corn rotation has a suitable production-to-investment ratio and has the highest profit,with a profit of 1,686.90 RMB per 666.7m² of land.On the whole,the soybean-silage corn rotation was suitable for the production and investment ratio and has the highest profit.The improvement of soil physical and chemical properties of salinized farmland and the effect of soil salt inhibition and alkali reduction were better.So Soybean-silage corn rotation was a planting mode suitable for the yield and environmental benefits in the Xiliaohe Plain of Inner Mongolia.