Study on the cover technology for the overwintering of highquality orchard grasses in Beijing

In order to resolve the overwintering problem of the several highquality orchard grasses, such as Trifolium repens, T. hybridum, Lotus corniculatus and Dactylis glomerata, the cover techniques were studied in the suburbs of Beijing by using three cover treatments (mulching, straw cover, shallow soil cover). The results showed that three treatments were effective for the orchard grass regreening and significantly increased the overwintering percentage. The turning green period of orchard grasses under mulching treatment was 13 and 20 days earlier than shallow soil cover treatment and the control respectively and the average overwintering percentage was increased by 21.8% and 60.8%, and the vegetation coverage on 1st April was increased by 41% and 51.3% respectively. The regreening period of grasses under straw covering was 4 and 8 days earlier than shallow soil cover treatment and the control respectively and the average overwintering percentage was increased by 16% and 45.3% respectively, meanwhile, the coverage on 1st April was increased by 14% and 22.7% respectively. Mulching treatment was the best for overwintering, but the straw cover treatment (535 g/m2, 5 cm layer) was better in terms of environmental protection, cost and practice.