施肥和混播对退化草地土壤和牧草产量的影响1

[Objective]The effects of fertilization and mixed sowing on soil nutrients and pasture yield in degraded grassland of Songnen Plain in western Heilongjiang province were studied in order to determine the optimal amount of fertilization and the ratio of legume to grass in mixed sowing for restoration of natural degraded grassland in this area.[Methods]The experiment took the natural light degraded grassland in Songnen Plain of western Heilongjiang province as the research object,six different fertilization treatments and two mixed sowing ratios of legume and grass pasture seed(Astragalus adsurgens Pall.and Elymus dahuricus Turcz.)were set up to explore the effects of fertilization and mixed sowing on soil nutrient changes and pasture yield.[Results]Fertilization could significantly improve available nutrients and pasture yield under the condition of determining the ratio of mixed sowing.The changes of soil nutrients in shallow layer were greatly affected by fertilization and mixed sowing than in deep layer.Fertilization,mixed sowing and their interaction had significant effects on the content of soil available nitrogen(p＜0.05).The variation trend of available nitrogen and available phosphorus in 0-10 cm soil layer were basically consistent with addition of nitrogen and phosphorus.The contents of total nitrogen,available nitrogen and available phosphorus in 0-10 cm soil layer of legume-grass in the 1:2 configuration mixed sowing were higher than in the 2:2 configuration under the same fertilization level.The conductivity of A6(N300P200K90)was significantly higher than other treatments(p＜0.05).The aboveground biomass in 1 m2 quadrat of legume-grass in the 2:2 configuration+N150P0K180 and legume-grass in the 1:2 configuration+N300P200K90 achieved 290.68 g and 254.31 g,were the highest respectively.[Conclusion]Considering forage yield and changes of soil nutrient,legume-grass in the 2:2 configuration mixed sowing,and fertilizer application of 150 kg/hm2 N can be recommended,based on these results.