Effects Of Root Cutting And Fertilization On Leymus Chinensis Grassland

Leymus chinensis grassland is the import mowing meadow and pasture in China. However, due to the climate changes and human disturbance, L. chinensis grassland shows different degress of degradation,which results in a decline in the yield and quality of grasses. Therfore, the urgent problem we are facing is how to improve and restore the degraded L. chinensis grassland. Using L. chinensis grassland in Jangjiadian, Da’an City, South Central Jilin Province as the research object. the randomized block design was adopted. In 2014, treatments of root cutting, root cutting combined with nitrogen and phosphorus fertilizer, root cutting combined with organic fertilizer were set up. Each nitrogen and phosphorus fertilizer and organic fertilizer treatment contained three concentration ratios respectively. The adjacent grassland without root cutting was selected as the control. There were a total of eight test groups. In 2015, each treatment of root cutting combined with different ratio of nitrogen and phosphorus fertilizer was divided into two equal parts, one part was treated without fertilization, the other part dealt with half a amount of the same fertilizer applied at last year. Vegetation characteristics,nutrient content and soil physical and chemical properties of different treatments were analyzed. The results are as follows:(1) Different treatments of root cutting and fertilization improved the coverage and of community,height and density of L. chinensis. The community coverage(99.67%) and the height of L. chinensis(58.49 cm) were improved obviously under the treatment of high level of nitrogen phosphorus fertilizer. The density of L. chinensis was improved obviously under the treatment of medium level of nitrogen phosphorus fertilizer, the amount of which was up to 1840 plants per square metre.(2) Different treatments of root cutting and fertilization significantly increased rhizome biomass of L. chinensis and underground biomass in 0-10 cm soil layer. In the first year under the medium level of nitrogen phosphorus fertilizer the rhizome biomass of l. chinensis and underground biomass increased most significantly. In the second year, the underground biomass(7.25g)was the highest under the mediumlevel of organic fertilizer, the rhizome biomass of L. chinensis(3.45g) was the highest under the high level of nitrogen phosphorus fertilizer. the biomass of l. chinensis was the highest under the high level of nitrogen phosphorus fertilizer(3) For two years, all of root cutting and fertilization treatments increased crude protein content of L. chinensis. The neutral and acid washing fiber contents of L. chinensis were reduced under the low and middle level of the same treatment.(4) Different treatments of root cutting and fertilization significantly increased total nitrogen and total phosphorus in 0-10 cm soil layer. It was the highest(0.26%) under the medium level fertilization in crack block. All the treatments increased the content of ammonium nitrogen in 0-10 cm soil layer. It was up to 8.38 mg/kg under high level of nitrogen and phosphoru fertilizer, which was the highest among different treatments. The content of available phosphorus was increased significantly in two years in 0-10 cm and 10-20 cm soil layer.