Mechanism On Increasing Crop Yield And Improving Its Quality Of Fly Ash-based New Multifunctional Soil Conditioner

Fly ash is a difficult-to-dispose bulk industrial solid waste,with an annual increase of more than 200 million tons,which is in urgent need of treatment.At the same time,the area of arable land in China is dropping sharply,the quality of arable land continues to decline,and food security has been seriously threatened.Based on the above national conditions,the predecessors put forward a new idea of chemically activated fly ash to prepare a new type of soil conditioner.Field tests have verified its significant yield and quality improvement effects on crops.However,the mechanism for increasing production and quality is still unclear,and it is urgent to be studied and revealed.To this end,this thesis first adopted simulated hydroponics to identify the key yield-increasing factors in the conditioner and clarify their interaction,and then revealed the effect of the conditioner on the improvement of soil quality through the study of the solidification effect of heavy metals in the contaminated soil.Finally,by studying the changes of soil physical and chemical properties and the results of field experiments,the mechanism of increasing production and quality of soil conditioners was further revealed from the other side.This paper mainly made the following innovative progress:(1)The effects of basic nutrient solution,conditioner,and four typical middle and trace elements on various traits of wheat during the early growth period were ascertained.The results show that there is an interaction between phosphorus,potassium and the trace elements contained in the soil conditioner.There are strong interactions between Fe and Mg,Mg and Ca,Ca and Si,while Mg and Si is the main contributor to wheat growth,with contribution rates reaching 66%and 55%,respectively.(2)Soil conditioner can solidify heavy metals in contaminated soil,especially for As and Cd.The study found that after applying the conditioner to the contaminated soil for 21 days,it showed a good curing effect.After the longest study time of nine weeks,compared with the blank control group,the active state content of Cd can be reduced by 40.6%,and that of As can be reduced by 54.7%,and the curing effects on Cr and Hg are 29.6%and 28.5%,respectively.The solidification of heavy metals by the conditioner can prevent crops from absorbing heavy metals from the soil,thereby reducing the risk of food pollution and ultimately achieving quality improvement;(3)Soil conditioner has a significant effect on enhancing the water holding capacity of the soil.With the increase in the amount of the soil conditioner,the improvement effect is further enhanced.When the addition amount is 100kg/mu,the soil water holding rate can be increased by 14.3%;Soil conditioner has a significant impact on the composition,degree of agglomeration and average particle size of soil aggregates and can significantly increase the content of soil water-stable aggregates.The content of water-stable aggregates in two types of soil can be increased by 42.3%and 20.0%,respectively.The mean weight diameter can be increased by 106.3%and 36.7%,and the geometric mean diameter can be increased by 24.2%and 14.7%;(4)Field test results confirmed that the fly ash-based soil amendment can stably and continuously increase the yield of corn,with a maximum yield increase of 52.3%,and the content of heavy metal elements in corn kernels did not change significantly,and their quality fully meeted the food safety standards of China and the European Union;The addition of the soil conditioner greatly improved the corn stem thickness and the lodging resistance ability of the corn stem.Compared with the blank group,the conditioner increased the lodging resistance ability of the corn stem by 37.3%.