The effects of weed competition, clipping and fertilization treatments on the productivity of cultivated meadows on the Qinghai-Tibetan Plateau

Abstract

The meadow ecosystem of the Qinghai-Tibetan plateau, the largest rangeland in China, has been degenerating recently from heavy grazing and soil erosion, resulting in decreased carrying capacity and canopy coverage. A field experiment was designed to test the effects of four treatments (density, fertilization, clipping, and species). The results show that a mixture of forage species provides the greatest increase meadow productivity and community stability. There was a 28% increase in target species yield in a two species mixture compared with a monoculture and a 103% increase in a three species mixture. Fertilization resulted in a 63% increase in the target species yield and a 54% increase in weed yield, but decreased weed abundance. Clipping had an adverse effect on meadow productivity and weed growth (abundance and yield), decreasing the target species yield by 46% relative to no clipping, and decreasing the weed yield by 6%. Elymus nutans was a competitive winner in all of the mixtures, regardless of treatment. A three-way ANOVA showed that the three species-mixture was the optimal combination for the development of a cultivated meadow. Clipping had no significant effect on the meadow yield but significantly decreased weed abundance. This three-species mixture not only increased yield, but also resistance to weed growth, thus making the mixture a good choice to improve rangeland, and provide benefits for both local economic development and environmental protection. Key words: Clipping, fertilization, mixture, rangeland, weed