新疆山地草甸植被群落特征及养分含量对围封和放牧的响应

【目的】 研究新疆山地草甸草地的植被群落特征和养分含量对围封和放牧的响应规律,分析其在不同生长季的动态变化规律,为退化草甸的恢复和科学管理提供理论依据。【方法】 在围封(5 a)与放牧条件下,以新疆山地草甸草地为对象,采用野外调查取样和室内分析相结合的方法,测定整个生长季(5~8月)的草地群落物种组成、数量特征、植物多样性以及牧草养分。【结果】 (1)围封和放牧条件下,禾本科植物在山地草甸草地中均占重要地位,其重要值分别为46.48%和26.91%,而在放牧区退化指示植物(如草原老鹳草、草原糙苏和紫花鸢尾等)所占比重增加;但围封降低了植物多样性。(2)植物群落数量特征对围封和放牧的响应明显,围封区群落植被密度、高度、盖度、地上生物量(7~8月)和地下生物量(0~10 cm)均高于放牧区。(3)与围封区相比,放牧区牧草粗纤维含量在生长季前期(5月)显著降低了18.95%,而牧草粗蛋白含量在生长季中期(6月)显著提高了的8.37%。【结论】 围封能提高草地的数量特征,增加优质牧草的比例,有效恢复退化草甸草地,但不利于植物多样性的维持;而在生长季前期适度放牧有利于提高群落的牧草品质。

Response of Community Characteristics and Nutrient Content of Edible Forage to No-Grazing and Grazing in Xinjiang Mountain Meadows

【Objective】 In order to provide theoretical basis for the restoration and scientific management of degraded meadows, the response rules of vegetation community characteristics and nutrient content to no-grazing and grazing in Xinjiang mountain meadows are clarified, and the dynamic change rules of vegetation community in different growing seasons are explored. 【Methods】 In this study, the no-grazing (5 a) and grazing mountain meadows grassland in Xinjiang was taken as the object. The species composition, quantitative characteristics, community diversity and forage nutrients of the grassland community during the whole growing season (from May to August) were determined and analyzed by field sampling and indoor analysis. 【Results】 (1) Under the conditions of no-grazing and grazing, gramineae played an important role in the mountain meadows grassland, accounting for 46.48% and 26.91%, respectively; While the proportion of degraded indicator plants (such as Geranium pratense, Phlomis pratensis and Iris ruthenicum) increased in the grazing area. But no-grazing reduced community diversity. (2) The response of plant community quantity to no-grazing and grazing was obvious. The vegetation density, height, coverage, aboveground biomass (from July to August) and belowground biomass (0-10 cm) in the no-grazing were all higher than those in the grazing area. (3) Compared with the no-grazing area, the content of plant fiber in the grazing area significantly decreased by 18.95% in the early part of the growing season (May), while the content of grass crude protein significantly increased by 8.37% in the middle part of the growing season (June). 【Conclusion】 No-grazing can improve the quantity of grassland, increase the proportion of high-quality pasture, and effectively restore degraded meadow grassland, but it is not conducive to the maintenance of community diversity, while moderate grazing in the early growing season is conducive to the improvement of community forage quality. Therefore, it is necessary to combine no-grazing and grazing in the utilization of this kind of meadow grassland, which has a positive effect on the sustainable development of grassland.