[Variations of water-soluble carbohydrate and nitrogen contents in Leymus chinensis and Phragmites communis under different stocking rates].

The variations of the contents of water-soluble carbohydrate and nitrogen in L. chinensis and Ph. communis under different stocking rates were studied by fencing grazing experiment on L. chinensis grassland. The results indicated that the water-soluble carbohydrate content in the base stem of L. chinensis and Ph. communis was the lowest (7.12% and 3.95%, respectively) at the beginning of growth period, and then increased gradually with seasons. There was no significant variation in the content of leaf water-soluble carbohydrate in the grasses. L. chinensis germinated earlier than Ph. communis, resulted in the difference between the water-soluble carbohydrate content in the base stem and the leaf of the grasses at the beginning of the experiment in May. Proper stocking rates were favorable for the increase of water-soluble carbohydrate content, and could accelerate the re-growth capability of the herbage. The nitrogen content was the highest at the beginning of growth period, and then decreased gradually with seasons, which was accorded with their phenology. Proper stocking rates could stimulate the assimilation of nitrogen in soil, and bring it to the ground, which improved the nutrition value of the herbage.