Study On Salt Control And Formula Fertilization In Soda Saline Alkali Soil

The main characteristics of soda saline alkali soil are high salt content,high alkalinity,heavy viscosity,difficulty in desalting and reducing alkalinity,and low crop yield.In this paper,according to the above characteristics of soda saline alkali soil,iron tailings and other improved materials were used to improve it.The movement and distribution of salt ions in the process of improvement and the effect of different modifiers on the effect of salt washing and alkali reduction of saline alkali soil were studied.At the same time,formula fertilization technology was used to optimize the amount of fertilizer,so as to improve the grain yield.The results are as follows:In the desalting stage,the p H value and total salt content of topsoil decreased with the increase of leaching water,and with the increase of iron tailings content,the effect of salt washing on soda saline alkali soil was significantly enhanced.When the thickness of anti return saline alkali layer of iron tailings is 10cm,the salt content of plough layer soil is reduced by more than 20%after three times of leaching,and when the content of iron tailings in mixed layer is 10%,the salt content of plough layer soil is reduced by more than 30%after three times of leaching.In the stage of salt accumulation,the anti return saline alkali layer and mixed layer of iron tailings can effectively inhibit the increase of soil p H value and the accumulation of total salt.When the thickness of anti return saline alkali layer of iron tailings is 10cm,the salt content of plough layer soil decreases by 25.0～32.7%during salt accumulation compared with that without adding iron tailings.When the content of iron tailings in mixed layer is 10%,the salt content of plough layer soil decreases by 19.6～36.4%after salt removal compared with that without adding iron tailings.Adding calcium chloride,magnesium sulfate and ferric chloride to soda saline alkali soil,the total salt content and p H value of the soil decreased,and the effect of adding ferric chloride was the most obvious.At the same time,the content of carbonate in soil also decreased significantly.When the mass ratio of CO₃^2-+HCO^-₃to the three chemical amendments was 1:0.8,the soil salt content decreased by 26.5%,21.6%and 30.4%.The"3414"scheme was used to measure soil formula fertilization,adjust the ratio of nitrogen,phosphorus and potassium fertilizer.According to the fertilizer effect equation,when the application rate of nitrogen fertilizer was 14.409（kg/mu）,phosphorus fertilizer was 3.6837（kg/mu）,and potassium fertilizer was 4.443（kg/mu）,the best yield of rice was 639.5326（kg/mu）.