Different grass community development and its effects on weeds in the apple orchard

The study was conducted on the community development of the grasses planted between the apple lines in the spring in the 1yearold apple orchard and their effects on the community development of the weeds. The natural weed community was taken as the control. The results showed when the grasses were planted in the spring in the Guanzhong Area of Shannxi, Trifolium repens, T.pretense, Lolium perenne, Festuca rubra and Festuca arundinacea quickly germinated and grew fast and developed into the sward in short time. There were less species, low density and coverage of the weeds in their community and with better effects on controlling the weeds. Poa pratensis, Agrostis stolonifera, Lotus cornioulatus, Dichondra repens and Cynodon dactylon were hard to germinate and grow could not come into sward until the autumn. They could not effectively control the weeds at that time. In the second year after planting, all the grasses except for D.repens and C.dactylon had the long green period, turning green in March and scorching no earlier than November. The creeping stem of D.repens grew horizontally at a medium speed and vertically kept 10～15 cm in all seasons. And it well covered the ground and without cutting in the growth season, the maintenance cost was less. T.repens, T.pretense, L.cornioulatus grew with a right speed and the cutting was dependent on their own. L.perenne and F.arundinacea grew quickly with high yield and was necessary to cut once in the first year, the cutting frequencies were dependent on the practical situation in the second year. A.stolonifera and F.rubra grew slowly and the cutting frequencies should be less than A.stolonifera and F.rubra. C.dactylon turned green later and scorched earlier than others. In addition, it grew horizontally and levelly too fast and was not good to plant it in the apple orchard. In conclusion, the suitability of grasses in the apple orchard was different and their growth characters were important for the orchard management. The coverage was highly relative to their controlling effects on the weed community development.