| Popis: |
Since the shelterbelt systems of 1,092,260 hm2 have been established for thirteen years from 1978, have formed 526,541 networks and protected 13,619,400 hm2 land in western part of Northeast region of China. According to the research work we did in the last five years, the results of research project showed that the shelterbelts had improved the environment significantly. A parameter of comprehensive effects of temperature, moisture and wind in the networks (Ec = 246.52−12.17E+0.58T+6.58U) which is an active method to estimate the effects of shelterbelt on farmland, is around 21.1–30.9mm/month improving the moisture state in dry season, helping the crop yield increasing on the average by 19.8%. The effective accumulated temperature (⩾ 10°C) increases by 71°C; the cropland area which suffered from wind and frost damage decreases by 80–90%, the grass coverage on the pastureland and grass production increases by 13% and by 49.4–72%, rough protein, rough fat and nitrogen-free extract of grass increase by 3.34%, 2.4% and 8.4% separately. A large number of fixing sand plantation has been established for over thirty years on shifting in Kerqin sand land; most sand duncs were stable; a great results got from 2,000hm2, experimental area in this region; the atmospheric transport dust decrease by 2,253t/y; absorbed dust 11.1t/ y and people’s eyes sick decrease by 75%. The sandy ecological system develops a relative stable plantation system, the grass, shrubs increase to 200 species from 20 species, insects increase to 400 from 30 species, birds to 60 species and other animals increase to 20 from a few species, the fungi increase to over 200 species. |
