Effects of clipping on forage yield and quality of mixedsown artificial grassland in Yangtze and Yellow river headwater region

The clipping experiment was conducted every ten days from July 26 to October 6 in the past two years on the mixedsown artificial grassland, which was established withmixture of Elymus nutans + Poa crymophila + Festuca sinensis + Puccinellia tenuiflora in the Black Soil Type degraded grassland of source region. The results indicated that the fresh grass yield of 2year old mixture grassland clipping firstly in August 26 was the highest for 31 933 kg/hm2, and 3year old mixture grassland clipping in August 16 was the highest for 9 520 kg/hm2. The determination of nutrient showed that the crude protein yield of mixture grassland clipping firstly in August 16 was the highest, and the 2year old grassland was 5 683 kg/hm2, 3year old grassland was 2 189 kg/hm2. So the period from August 16 to 26 was the optimum clipping time of the perennial artificial grassland in the area.