Effects Of Fertilization And Clipping On Productivity And Species Diversity In Leymus Chinensis Grassland

Leymus chinensis is the dominant specie in the northeast saline-alkaline meadow and it has high feeding value.It works as an important role not only in the grass recovery and reconstruction,but also in ecological management.All the time,how to manage the grassland(fertilization,mowing)and how to improve the grassland productivity and diversity of species are theoretical and practical problem to be solved in our country.And all above problems are important for coordinated development of ecological and economic construction.Experimental design using randomized block-split-plot methods,the processing time for nitrogen(split-plot for nitrogen fertilizer levels:0g/m~2,12g/m~2,24g/m~2)is fall fruitnutrition during.At the same time,clipping treatment levels is no clipping,stubble 5cm and stubble10 cm.Our experiment intends to explore the effects of different fertilizer rate and stubble levels on grass productivity and species diversity on L.chinensis grassland in Songnen plain.Results are as follows:1.The fall fruit nutrition during nitrogen application extremely influenced herbage yield per unit area in the following year.With the increase of fertilizer rate,herbage yield increased.And the community dominant species-L.chinensis production increased significantly.Stem weight,leaf weight and plant height increased significantly.On account of L.chinensis tended to produce buds or ramets in reproductive strategies,the density of L.chinensis had significant response to fertilizer,it increased with fertilizer rate.Fertilizer rate had no obvious significance on single L.chinensis weight because of resources limited.Fertilizer had no obvious significance on the yield of other grass,the number of yellow leaves and green leaves.2.The fall mowing had no extremely influence on the following herbage yield.In the second year,mowing had significant impact on the following L.chinensis production,leaf weight and density.All three elements are increased.Under mowing process,plant height was extremely lower than no mowing plants.Fertilizer and mowing on plant height existed interaction effects.After mowing,plant photosynthetic ability became weak and they were lack of nutrients,which resulted in a significant decline in single L.chinensis weight.Mowing had no obvious significance on other grass yield,the number of yellow leaves and green leaves.Stubble 5 cm and stubble 10 cm had no significant effects on herbage yield and each element of herbage yield.3.After fertilizer application in the relative second year,seed yield increased significantly.Fertilizer had significant effects on the following thousand seeds weight,which increasedsignificantly.Fertilizer had no obvious significance on heading number,heading rate and seed number per spike.4.The fall mowing application extremely increased the seed yield,heading number,heading rate,floret number and thousand seeds weight.There was no significant influence on seed number per spike.Different stubble height had no significant influence on seed yeild and each element of seed yield.The highest seed yield was 19.33kg/ha,which no fertilizer and stubble 5 cm(N0Y1)processing.5.Different fertilizer and mowing levels had no significant effects on the species number.The highest species number was 5.2/m~2,which no fertilizer and no clipping(N0Y0)processing.In the second year after fertilizer and mowing.Species number was negatively correlated with community aboveground biomass.