Effects Of Biochar-based Phosphate Fertilizer On Photosynthetic Characteristics And Root Growth Of Stipa Krylovii

As a new functional material,biochar has attracted extensive attention in agriculture and is often used as a soil amendment.In northern China,the grassland was heavily utilized,seriously degraded,and seriously deficient in phosphorus.Stipa krylovii plays an important role in the productive use of grasslands as a major population building plant in northern grasslands.Fertilization is an important method to restore degraded grassland,but biochar-based phosphate fertilizer has little research on the improvement of natural grassland.in this study,Stipa krylovii was taken as the research object,and six fertilizer treatments were set up:Control（CK）,diammonium phosphate（D）,biochar（B）,low biochar-based phosphate fertilizer（LBD）,medium biochar-based phosphate fertilizer（MBD）and high biochar-based phosphate fertilizer（HBD）.By measuring the above-ground indeaes such as tiller number and biomass;net photosynthetic rate（Pn）,stomatal conductance（Gs）,intercellular CO₂concentration（Ci）,transpiration rate（Tr）,relative variable fluorescence intensity（Vj）,QA^-reduced rate（Mo）,photochemical performance index(PI_ABS),electron transport rate（Ψo）;Root number,root length,root surface area and root volume;soil moisture,and soil conductivity.The results showed that:（1）HBD fertilization treatment significantly increased the tiller number of Stipa krylovii;LBD,MBD,and HBD fertilization treatments significantly increased the Aboveground biomass of Stipa krylovii leaves.D,B and HBD fertilization treatments promoted the relative growth rate and leaf area of Stipa krylovii leaves.（2）HBD and MBD fertilization treatment has improved the water use efficiency of Stipa krylovii.Under HBD fertilization treatment,the net photosynthetic rate（Pn）and transpiration rate（Tr）of Stipa krylovii increased,while the intercellular CO₂concentration（Ci）decreased.LBD,MBD,and HBD fertilization treatment increased the photochemical performance index(PI_ABS)and electron transfer rate（Ψo）of Stipa krylovii.Moreover,the relative variable fluorescence intensity（Vj）and the initial slope（Mo）of the OJIP curve of Stipa krylovii were reduced.（3）D,B,LBD,MBD and HBD fertilization treatment have significantly increased the root length production,root surface area and root volume of Stipa krylovii.Therefore,each fertilization treatment has promoted the growth of the Stipa krylovii.In summary,the application of high biochar-based phosphate fertilizer（HBD）has promoted the growth of the upper part of the Stipa krylovii,The number of tillers,aboveground biomass,relative growth rate of leaves and leaf area of Stipa krylovii were promoted.LBD,MBD,and HBD fertilization treatment promoted the photosynthesis of Stipa krylovii and the growth of the root system.Based on the above results,preliminary speculation that the use of high biochar-based phosphate fertilizer（HBD）to improve the vegetation conditions of the hometown of the Stipa krylovii,and repair the degraded grassland.