Effects Of Silicone Compound Fertilizer On Water And Salt Dynamics Of Coastal Saline Soil And Maize Yield

Coastal saline-alkali land is an important reserve land resource in China,and its improvement and resource utilization are of great significance to alleviate the pressure on agricultural land.Silicone compound fertilizer is a new type of chemical fertilizer developed in China in recent years,with high slow-release performance,biodegradability,no environmental pollution and other characteristics,and has good practical value for agricultural production and saline-alkali land improvement.In this thesis,the medium coastal saline soil on the west coast of Bohai Bay was taken as the research object,and the maize field experiment was carried out at the Haixing Experimental Station of the Chinese Academy of Sciences in Cangzhou City,Hebei Province,and the test was set to5 treatments:no fertilization（CK）,600 kg·hm^-2diammonium（C1）,375 kg·hm^-2silicone compound fertilizer（C2）,750 kg·hm^-2 silicone compound fertilizer（C3）,1125 kg·hm^-2silicone compound fertilizer（C4）,The effects of different application amounts of silicone compound fertilizer on the dynamic changes of water and salt in coastal saline soil and maize yield were explored,in order to provide a theoretical basis for the improvement and yield increase of saline soil in the coastal plain on the west coast of Bohai Bay,and the main research conclusions are as follows:（1）The application of silicone compound fertilizer can increase soil moisture content,reduce soil salt content,and play the role of salt control and water retention,and with the increase of application amount,the better the improvement effect.In the 0～100 cm soil layer,with the increase of soil depth,the soil water content and salt content showed an increasing trend,and the change trend and salt content of Na⁺and Cl^-were consistent.Compared with CK,the soil moisture content of silicone compound fertilizer was increased to different degrees,and the water content of different growth stages was different,and the C4 treatment at the seedling stage had the highest increase（30.22%）compared with CK.The application of silicone compound fertilizer significantly reduced the soil salt content,and with the increase of fertilization amount,the soil salt content decreased,and the salt content decreased to different degrees at different growth stages,the C4 treatment at the jointing stage decreased the most（69.42%）compared with CK salt content,and the C4 treatment with Na⁺and Cl^-content in the mature stage decreased the most（70.55%and 74.76%）compared with CK.Comprehensive analysis showed that increasing the application rate of silicone compound fertilizer could provide a better soil water and salt environment for the growth and development of crops in coastal saline-alkali land.（2）The application of silicone compound fertilizer can reduce soil bulk density and soil pH,improve soil aeration and hydraulic characteristics,and increase soil alkaline hydrolyzable nitrogen,available potassium and available phosphorus content,and the better the improvement effect with the increase of application amount.With the increase of soil depth,soil pH first increased and then decreased along the soil profile,soil bulk density increased slowly,and soil aeration,hydraulic characteristics and fertility decreased.All treatments of silicone compound fertilizer could effectively reduce the soil bulk density,and the effect of increasing the application rate and reducing the soil was more significant,and the soil bulk density of C4 treatment was the largest（13.85%）compared with CK.The soil pH value of each treatment of silicone compound fertilizer was reduced compared with CK,and the reduction rate was different at different growth stages,and the C4 treatment at maturity was the largest（6.75%）.Compared with CK,the aeration,hydraulic characteristics and fertility of the soil were improved to different degrees,and the indicators of C4 treatment had the highest increase.Comprehensive analysis showed that increasing the application rate of silicone compound fertilizer could provide suitable soil structure and nutrient conditions for the growth and development of crops in coastal saline-alkali land.（3）The application of silicone compound fertilizer can increase the plant height,stem thickness,ear coarseness,biomass,ear number and yield of maize,and with the increase of application amount,the higher the yield increase effect.During the whole growth period of maize,the change trend of plant height of maize treated was consistent,the increase rate was lower in the early stage,the increase rate was higher in the medium term,and the later stage tended to be stable,and the C4 treatment had the largest increase（61.81%）compared with CK.Compared with CK,the growth traits of other treated maize were improved to a certain extent.Compared with CK,each treatment significantly increased the ear weight and ear number of corn,but the effect on hundred grain weight was not significant,so the increase of corn ear number contributed greatly to the increase of corn yield,among which,Among them,the yield of maize treated with C4 was the highest,with an increase of 56.86%compared with CK,followed by 47.06%higher yield from C3 treatment than CK,and the difference between C1 treatment and C2 treatment was not significant.（4）The correlation between water salt,physicochemical properties and nutrients and maize yield in coastal saline soil showed that the correlation between maize yield and soil indicators in each growth period was different,soil moisture content at seedling and jointing stage was significantly positively correlated with maize yield,and soil salinity,Na⁺,Cl^-and crop yield were significantly negatively correlated at jointing,filling and ripening stages.In addition,capillary porosity and available potassium were significantly positively correlated with maize yield,which had an important impact on maize yield increase.In summary,the application of silicone compound fertilizer can effectively improve the physical and chemical properties of coastal saline-alkali soil,improve the saline-alkali soil water and salt environment,improve soil nutrients,increase crop yield,and provide a new model for the rational development and utilization of coastal saline-alkali land.