Effects Of Different Forages On Soil Properties Of New Land In Yan’an Area

The gully control and land reclamation project is a new project that can create a large area of high-quality flat cultivated land in Yan ’an area.It is also a comprehensive ecological and people ’s livelihood project integrating various projects.The gully control and land reclamation project is aimed at the special landform of the hilly and gully area of the Loess Plateau.It is a new model of gully land consolidation that uses modern machinery to quickly fill the gully and cover the soil,and the comprehensive construction of Tianba canal road forest.With the continuous expansion of new land area,in order to make sustainable use of new land,effective measures need to be taken to improve soil quality and make it play its functions of channel protection,ecological service and agricultural production.In this study,based on the soil quality problems of the new land created by the " gully control and land reclamation " project in Yan ’an area,the typical new land was taken as the research object,and the physical properties,chemical properties and microbial diversity of the soil in the new land were analyzed by combining outdoor sampling with indoor testing and single factor analysis.The effects of different forage planting treatments on the soil properties of the new land were studied,and the results of the effects of different forage treatments on the soil properties were clarified.The most suitable high-quality forage for soil improvement in the new land was explored to improve the soil quality of the new land and make it play its role in gully protection,ecological services and agricultural production.In this study,different forage treatments were carried out on the new land in Yan ’an area,which were Festuca arundinacea,Medicago falcata,Elymus dahuricus,Trifolium repens and blank control.In 2020,2021 and 2022,samples were taken from the plots and brought back to the laboratory for the determination of physical and chemical indicators and microbial diversity analysis,and the results were analyzed.The effects of different forage treatments on soil improvement were studied,and the following conclusions were obtained:1.This study found that after grass treatment,the bulk density of the soil in the new land was reduced,the total soil porosity between 0-30 cm was increased,and the soil water content in the soil was increased.This study shows that planting forage can promote soil moisture,increase nutrients,reduce soil p H,and improve soil particle composition,thereby improving soil fertility.2.After the grass treatment,the content of available phosphorus decreased,after the grass sowing,the grass in the growth period will absorb the available phosphorus nutrients in the soil,which will lead to the decrease of available phosphorus content in the soil.After planting grass,the soil total phosphorus increased significantly,indicating that planting grass in the new land can effectively improve the supply of soil total phosphorus.This study showed that after planting forage grass,the soil available potassium treated by planting forage grass was significantly higher than that of the blank control,so planting forage grass could significantly increase the soil available potassium content.After planting grass,soil organic matter increased significantly compared with the blank control.After two years of treatment,white clover treatment increased nitrate nitrogen,and the soil nitrate nitrogen in the treatment of planting forage grass changed significantly.3.In this study,soil microbial community and diversity were studied by highthroughput sequencing,and a total of 14197 OTUs were obtained,ranging from 215 in PCJ22 to 446 in CK22.Sequence analysis showed that the microorganisms in the grass treated samples were assigned to 35 different phyla,and the most dominant phylum was Proteobacteria.The relative abundance in soil samples was 88 %-94 %,which was significantly higher than that of other phyla.At the genus level,766 different bacterial genera were detected,and the overall composition of bacterial genera in different samples was significantly different.Pseudomonas,Herbaspirillum,Herminiimonas and Stenotrophomonas were the dominant species.In the sample BSY20,the relative abundance of Herminiimonas was the highest,accounting for 19.17 %,which was the dominant genus of BSY20.In other samples,the relative abundance of Pseudomonas was the highest.In other soil samples,the relative abundance of Pseudomonas,Herbaspirillum,Herminiimonas and Stenotrophomonas decreased in turn.4.In this study,through the determination of a variety of indicators,through the analysis and integration of data results,Elymus treatment in soil water content,soil porosity,soil p H,soil total phosphorus,soil available potassium indicators,are the best impact on soil properties,soil organic matter indicators,white clover and Elymus for the greatest impact,in the microbial indicators,the effect of white clover treatment is the best.Elymus dahuricus in each index,the performance is more prominent.