Effect Of Different Free-range Broiler Vears On Plant Community And Seed Bank In Qilian Mountain

"Breeding poultry and controlling grasshopper" as a newly accepted grassland production model, has been successfully used in the controlling grasshopper disaster and breeding organic broiler, but it’s effects on ecosystem and seed bank is unknown. To measure the effect of free ranging chicken on ecosystem, soil property and seed bank, studying was conducted on the Qilian Mountain grassland. And analyzed the variances of soil property, the community component and the canopy seed bank, ground seed bank and soil seed bank after continuous years grazing, the detailed results as follows:1. In different soil depth, SOC, TN and A-P continuously increased after birds grazed on the grassland year by year. But there is no significant various on soil bulk density, porosity, moisture content and pH value.2. There is no significant various on richness, diversity index, evenness, community height and coverage(P>0.05) in different grazing years, except aboveground biomass significantly increased after chicken freely grazed(P<0.05).3. the leguminous, Poaceae and Cyperaceae plant canopy seed bank significantly reduced(P<0.05) after continuous grazing. The others plant canopy seed bank increased in the first year, but there’s no various in the followed grazing years.4. The Leguminous plant, Cyperaceae and The others seed bank significantly increased in the first year, but contrast in the following grazed years, the Poaceae ground seed bank as2.4times,2.7times,3times respectively as the check blank.5. Generally, the majority soil seed bank stayed in0-5cm, especially the leguminous, but Cyperaceae seed bank decreased as grazing years indeed in0-5cm and5-10cm. Poaceae soil seed bank found mainly in the0-5cm, and it’s increased in the two layers separately. The others seed bank significantly increased after chicken freely grazed in two soil layers.6. The amount of leguminous and Cyperaceae seed bank continuously decreased after chicken freely grazed. Poaceae seed bank showed no significant various, and others plant seed bank increased in the first grazing year, but decreased in the following grazing years.Through "breeding poultry control grasshopper" model, grasshopper effectively be controlled at threshold value, but impact on the grassland plant community, soil property and seed bank. So this study was launched to demonstrate the change of those items, also to assess the suitable free ranging chicken model on the grassland, provide basic data for reasonable pasture grazing.