Interference Effect Of Exogenous Organic Matter On Carbonate In Light Chernozem

The light chernozem soil is one of the main soil types in agricultural production in Jilin Province.The low content of organic matter and high content of carbonate result in the relatively poor fertility of the light chernozem soil.In order to ensure the sustainable utilization of light chernozem soil,it is urgent to improve it and improve its fertility.At present,the main measure to improve soil fertility is to import organic materials into the soil,and the addition of organic materials can improve the accumulation and redistribution of inorganic carbon at the same time.In this paper,the effects of organic materials on carbonate,exchangeable ions,functional groups and the change of organic carbon and inorganic carbon 13C in light chernozem soil of Jilin Province were studied by the laboratory cultivation experiment.The changes of carbonate and exchangeable ions in different particle size（micro）aggregates were compared.The main results were as follows:Firstly,When straw enters the light chernozem soil,it will decompose to produce a large amount of CO₂ under suitable temperature and humidity conditions,and react with soil moisture to produce HCO₃^-,which increases the content of HCO₃^-.When straw is added to the light chernozem soil,the soil pH increases.At the same time,the application of straw can effectively increase the content of exchangeable Ca²⁺,Mg²⁺,K⁺,Na⁺.Secondly,After the organic-inorganic compound fertilizer enters the light chernozem soil,the organic-inorganic compound fertilizer increases the acid-base buffering performance of the soil,and the organic fertilizer is usually alkaline,which greatly improves the soil pH;the organic-inorganic fertilizer decomposes and releases CO₂ and reacts with the water in the soil to produce HCO₃^-,thus increasing the content of HCO₃^-and promoting the combination of exchangeable Ca²⁺,Mg²⁺and HCO₃^-to form carbonate,so organic-inorganic fertilizer reduces the content of exchangeable calcium and magnesium ions and promotes the precipitation of carbonate.Thirdly,With the addition of organic materials,Compared with the control,the contents of carbonate and exchangeable calcium ions in macroaggregates and exchangeable magnesium ions in small-size micro-aggregates of Chernozem increase.The content of aggregate carbonate in soil decreased first and then increased with the decrease of grain size.The content of aggregate carbonate in soil with straw treatment increased with the decrease of grain size.The distribution of exchangeable calcium and magnesium ions in（micro）aggregates decreased first and then increased with the decrease of grain size.The adsorption and retention of exchangeable ions in soil by small size microaggregates are stronger.Forthly,With the extension of incubation time,the dynamic change of the value ofδ13C in the light chernozem soil was almost small.Compared with the control,the value of soil organic carbon and inorganic carbon increased,and the higher the amount of straw added,the higher the value of soil organic carbon and inorganic carbon.Finally,The functional groups of different treatments were similar.It mainly contains carbonates,carbohydrates,carboxylic acids,phenols,alcohols,fatty acids and amides.