Effects Of Different Phosphorus Levels On Growth And Nutrient Utilization Of Leymus Chinensis

In order to explore the response of the growth and nutrient utilization of the different phosphorus levels,this experiment was studied by the Leymus chinensis and set up four phosphorus gradients（0,70,140,210 kg/ha）.The effects of different phosphorus levels on soil fertility,Leymus chinensis growth characteristics and nutrient utilization of soil were analyzed,and the correlation analysis was carried out on the growth index and photosynthetic physiological parameters of the Leymus chinensis.In order to determine the optimal amount of phosphorus in the growth and construction of Leymus chinensis,the results of the study can not only be used for the further implementation of phosphorus fertilizer,but also provide reasonable application management basis for the construction of artificial Leymus chinensis in Xinjiang area.The results of the study are as following:1.During the seedling period and jointing period of the Leymus chinensis,the amount of phosphorus and organic matter in the soil increases with the increase of the phosphorus,which decreases after the increase.The content of total phosphorus in soil was the highest under P₂₁₀ treatment at each stage.According to the correlation analysis,the content of available P in the soil was significantly positively correlated with alkaline phosphatase activities in the seedling stage.2.Phosphorus application in the range of 140 to 210 kg/ha was beneficial to increase plant height and biomass accumulation of Leymus chinensis.The response of photosynthetic rate of Leymus chinensis to soil phosphorus application was different.With the increase of phosphorus application intensity,the net photosynthetic rate showed a trend of first increasing and then decreasing.The maximum photochemical efficiency（Fv/Fm）,PSII activity and initial fluorescence（Fo）of chlorophyll fluorescence appeared in the range of phosphorus application intensity from 70 kg/ha to 140 kg/ha,while Fo/Fm was the minimum.Correlation analysis showed that total biomass and plant height of Leymus chinensis were significantly correlated with net photosynthetic rate.Based on the comprehensive analysis,the photosynthetic characteristics of Leymus chinensis were significantly affected by different phosphorus application levels,and finally the biomass accumulation of Leymus chinensis was affected.3.With the increase of phosphorus application,the contents of nitrogen and phosphorus in different parts of Leymus chinensis were firstly increased and then decreased,and the lower content was the highest in P₁₄₀ treatment.Compared with CK,the content of phosphorus in the aboveground of each phosphorus application level increased by 14.11%,29.95%and 23.99%.In the jointing stage and harvest stage of Leymus chinensis,the potassium content in the aboveground plant increased with the increase of phosphorus application,and the potassium content in the upper ground was the highest in the P₂₁₀treatment.In each growth period,the contents of total phosphorus and total nitrogen in each part of Leymus chinensis increased first and then decreased with the increase of phosphorus application,and the content was the highest in P₁₄₀ treatment,and continued phosphorus application did not improve the contents of nitrogen and phosphorus in Leymus chinensis plants.The accumulation of N and P in different parts of Leymus chinensis increased first and then decreased with the increase of P application rate.The accumulation of N and P in different parts of Leymus chinensis reached the maximum at P₁₄₀,while the accumulation of K increased with the increase of P application rate.The accumulation of K in different parts and total K accumulation reached the maximum at P₂₁₀.With the increase of P application rate,P fertilizer utilization rate firstly increased and then decreased,and the specific performance was P₁₄₀>P₇₀>P₂₁₀.In conclusion,within a certain range of P application,the growth of Leymus chinensis characteristics and photosynthetic characteristics,as well as the nutrient accumulation and utilization rate of phosphate fertilizer will with the increase of P levels was a trend of increase.When the phosphorus content of more than 140 kg/ha,with the increasing of application rate of phosphoric fertilizer to produce inhibition,considering the economic benefit and cost.It is suggested to apply phosphorus in the range of140-149.55 kg/ha to guide the production and construction of artificial Leymus chinensis grassland.