Evolution Characters And Sustainable Utilization Of Organic Matter In Different Fertilization Systems Of Red Soil In Yunnan Province Summary

Soil organic matter is an important indicator to evaluate the soil quality.The change of soil organic matter is affected by many factors.Among them,fertilization is one of the most direct and major agricultural measures which affects the variation of soil organic matter.The purpose of this study was to investigate the evolution of soil organic matter in different fertilization systems of red soil,to explore the evolution direction and velocity of organic matter,to study the organic carbon storage changes of soil profile and yield effects of soil organic matter in different fertilization regimes.In order to put forward countermeasures and suggestions for sustainable utilization of red soil.In this study,a long-term fertilization experiment(1978-2015)on corn in red soil of Qujing dryland in Yunnan Province was carried out to experimental research.Ten different fertilization treatments include CK,N,NP,NM,NMP and NP + K,NP + K,NMP + K,NM + P,N + MP in the experiment.The research gets the following conclusion:1.It clarifies the evolvement rule of red soil organic matter content in long-term different fertilization.The results showed that,after 38 years different fertilization of the long-term experiment of red soil in dry land,the content of organic matter of treatment with long-term non-fertilization decreases slowly;the content of organic matter maintains or increases slowly with treatment of long-term application of chemical fertilizers,it is also slightly higher than that with long-term non-fertilization,and the higher the crop yield,the higher the content of soil organic matter;the soil organic matter content can be improved significantly with treatment of long-term application of organic fertilizers,or combined application of organic fertilizers and chemical fertilizers,and the effect is better than application of chemical fertilizer alone or two facilities.2.It elaborates the response relationship of total organic carbon to organic carbon inputs with the long-term different fertilization under red soil in dry land.The results showed that,there is a significant progressive correlation between the change of soil organic carbon reserves and the input of Cumulative Carbon in red soil of dry land.The input of the minimum Cumulative Carbon for maintaining the initial SOC level was 9.8 t / ha.The carbon sequestration efficiency of red soil of dryland can change with the increase of carbon input.When organic carbon increases with the increase of carbon input to a certain level,the carbon sequestration efficiency is lower than that of low organic carbon level.3.It analyzes the change characteristics of soil profile organic carbon under with the long-term different fertilization under red soil in dry land.The results showed that different fertilization measures could significantly change the organic carbon storage of 0-100 cm soil.The rule of distribution of organic carbon of 0-100 cm soil profile showed that 0-20 cm soil organic carbon storage is the highest,and 20-100 cm soil gradually decreased with long-term different fertilization under red soil in dry land.It also showed that long-term application of organic fertilizers,especially combined application of organic fertilizers and chemical fertilizers,could effectively increase the organic carbon content in 0-100 cm soil,which was better than single fertilization or combined two chemical fertilizers.It indicates that combined application of organic and inorganic fertilizers was a better management measure of improving red soil fertility.4.It ascertains the relationship between red soil of dryland organic matter,soil nutrients and grain yield.The results showed that there was a close relationship between soil nutrient content and soil organic carbon content..Soil organic carbon was significantly correlated with soil total nitrogen,available nitrogen,total phosphorus,total potassium and available potassium(P <0.001).At the same time,the soil organic matter and corn yield was a significantly linear relationship before soil organic matter of red soil of dryland reached the threshold value.This experiment also shows that the soil organic matter of Yunnan red soil of dry land long-term experimental point has not yet reached the threshold value,we must continue raising soil fertility.