Verification Of The Effect Of Nano Magnesium Fertilizer On Preventing And Controlling Magnesium Leaching From Yellow Soil In Southwest China And Exploration Of Its Mechanism And Principle

The yield and quality of crops are greatly affected by magnesium,and magnesium deficiency during growth and development is an important factor affecting crop yield and quality.In the southwest region,where high temperatures and rainfall are common,as well as soil acidification,leaching losses of soil magnesium have been severe,leading to a severely reduced amount of available magnesium in the soil.The lack of magnesium has gradually become a limiting factor for crop yield and quality in the southwestern region;To alleviate the problem of magnesium deficiency in soil and promote crop growth and development,the application of magnesium fertilizer has become an important measure to increase crop yield and quality,as well as increase the effective magnesium content in soil.At present,traditional magnesium fertilizers have shortcomings.Quick available magnesium fertilizers have quick effects and release,but due to their high water solubility,most magnesium is lost through leaching and runoff;While slow-acting magnesium fertilizer is less prone to leaching than quick-acting magnesium fertilizer,its release and effectiveness are slow,and it cannot meet the magnesium demand of crops during the rapid growth period in a short time.Therefore,the practice and application of new nano magnesium fertilizers is imminent,and suitable magnesium fertilizers are of great significance in preventing and controlling magnesium leaching,improving magnesium fertilizer utilization,and reducing environmental costs.This study verified the inhibition and control effect of nano magnesium fertilizer on soil magnesium leaching through indoor soil column simulation and outdoor leaching experiments,and further explored the deep mechanism and principle of nano magnesium fertilizer inhibiting and controlling magnesium leaching.In the indoor soil column simulated leaching experiment,Nano magnesium oxide treatment and Nano magnesium hydroxide treatment significantly reduced the amount of magnesium and calcium leaching from soil.Compared to magnesium sulfate,the leaching amount of magnesium treated with Nano magnesium oxide and Nano magnesium hydroxide decreased by 15.00% and 23.35%,respectively.At the same time,Nano magnesium hydroxide significantly increased the exchangeable magnesium content of soil by268.16%;Compared with conventional magnesium hydroxide,the exchangeable magnesium content of soil treated with Nano magnesium hydroxide increased by 152%.Compared with magnesium sulfate treatment,the exchangeable magnesium content of soil treated with Nano magnesium oxide and Nano magnesium hydroxide increased by74.58% and 213.25%,respectively.In the indoor soil column simulation leaching and water infiltration experiment,Nano magnesium oxide and Nano magnesium hydroxide treatments also significantly reduced the concentration and amount of magnesium in the leaching solution.The magnesium concentration of the leaching solution treated with Nano magnesium oxide and Nano magnesium hydroxide decreased by 74.16% and 85.40% compared to that treated with magnesium sulfate,respectively;The magnesium concentration of Nano magnesium hydroxide treatment was 21.94% lower than that of conventional magnesium hydroxide treatment.In terms of magnesium leaching amount,the magnesium concentration in the leaching solution treated with Nano magnesium oxide and Nano magnesium hydroxide decreased by 73.76% and 85.82% compared to that treated with magnesium sulfate,respectively;The leaching amount of Nano magnesium hydroxide treatment is 25.93% lower than that of conventional magnesium hydroxide treatment.By calculating the specific surface area of soil particles and analyzing the micro interaction forces between soil particles,it is concluded that the application of Nano magnesium fertilizer enhances the adsorption capacity of soil particles for magnesium ions and water,and slows down the infiltration of water due to gravity and other reasons;Moreover,it allows the soil colloid to contact with water and exchange nutrients for a longer time,which is conducive to retaining more fertilizer nutrients in the soil.In the topsoil,the specific surface area of soil particles treated with Nano-magnesium fertilizer is higher,matching with the higher exchangeable magnesium content in the same layer of soil,which can be more convenient for nutrient exchange of soil colloids and nutrient absorption by crop roots.Based on the comprehensive research content and result analysis,two types of magnesium fertilizers,Nano magnesium oxide and Nano magnesium hydroxide,can not only significantly reduce the leaching amount of magnesium in yellow soil,but also significantly increase the content of exchangeable magnesium in soil;Nanometer magnesium fertilizer has an impact on the soil adsorption and desorption process,water migration process,and micro forces between soil particles through its Nano characteristics,thereby increasing the soil’s adsorption capacity for water and nutrient elements,achieving the result of reducing leaching losses.After comprehensive analysis,Nano magnesium hydroxide can better achieve the effect of reducing leaching loss,improving soil magnesium nutrient content,improving fertilizer utilization efficiency,and also better meet the nutrient requirements for crop growth and development.