Amelioration Technology Of Desertified Soil Based On Humification Of Organic Matter In Yellow River Basin

The Yellow River Basin is located in the north of my country,with a drainage area of more than 750,000 square kilometers,spanning the western,central and eastern regions of China.The Yellow River Basin is not only an important ecological security barrier in my country,but also an important area for my country’s population activities and economic development.However,due to climate change and other reasons,the ecological environment in some areas of the Yellow River Basin is fragile,especially in the middle and upper reaches of the region,the problem of land desertification still exists.The area of land desertification in the Yellow River is about 25%of the total area of the basin,and the land area with moderate and severe desertification accounts for17.5%,which affects the development of the area in the basin to a certain extent.There are abundant agricultural organic solid wastes in the Yellow River Basin,Which are rich in organic matter and have great potential for resource utilization.After treatment,they can be used to improve desertified soil,which can not only enrich soil organic matter content,improve soil quality,reduce environmental pollution,promote resource utilization of waste organic matter,but also increase soil carbon sequestration,which is conducive to carbon emission reduction,effectively strengthen the Ecological and environmental governance in the Yellow River Basin and promotes the high-quality development of the whole basin.In this study,the humification of organic matter was applied to the desertified soil in the Yellow River Basin as an organic amendment,and its effects on the water holding capacity of the desertified soil,the fertility level of the desertified soil,the enzyme activity of the desertified soil and the bacterial community structure were analyzed.On this basis,a desertified soil improvement technology based on humification of organic matter is proposed.The main conclusions are as follows:（1）After the organic amendment was applied to the desertified soil in the Yellow River Basin,the electrical conductivity of the soil increased significantly,and the contents of organic matter,alkali-hydrolyzable nitrogen and available phosphorus all increased to varying degrees.Organic amendments had the effect of decreasing soil p H at low application rates and increasing soil p H at high application rates.（2）（2）Organic amendments can significantly slow down the infiltration of soil water in the vertical direction,so that the water in the shallow soil can be kept at a high level for a long time,and at the same time,it can block the loss of water in the deep soil and reduce the loss of soil water.And this effect is related to its application rate,the best effect is 30%application rate,and the cumulative evaporation is reduced by48.66%.（3）The improvement effect of the amendment on sandy soil was further verified by the ryegrass pot experiment.The application of organic amendments can reduce soil p H,but the reduction effect is related to the application rate.Organic amendments can also improve soil conductivity and NPK content,and the improvement effect is positively correlated with the application rate.After planting,soil nutrient content in each treatment group was accumulated,and all were higher than those in the control group.The application of organic amendments can also improve the activity of soil enzymes,enrich the species of soil bacteria,and improve their diversity.The soil urease activity,sucrase activity and catalase activity were increased by 14.25 times,4.33 times and 0.49 times,respectively,compared with the control group.The results of bacterial Alpha diversity index showed that the Ace index,Chao1 index,Shannon index and Simpson index of soil bacteria all increased compared with CK.（4）The application of organic matter humification products can improve the fertilizer and water storage capacity of desertified soil,and at the same time increase soil nutrient content..The results of soil fertility grading and evaluation showed that with the increase of the dosage of amendments,the levels of each index of the desertified soil were improved,but the improvement effect of total nitrogen and alkali-hydrolyzed nitrogen was relatively poor.The results of water holding test and comprehensive analysis of ryegrass growth showed that the optimum application rate was 45%.When the application rate was 45%,the mitigation effect of soil carbon sequestration on global warming was 125.45 t CO₂-eqv·hm^-2.