关键词: 呼伦贝尔草原, 刈割时间, 留茬高度, 群落特征, 牧草质量

Abstract: In order to select a best mowing regime for natural grassland in Hulun Buir with highly efficient hay-making and sustainable utilization, we conducted an experiment to examine the effects of mowing time (July 31, August 10, August 20, August 30, and September 9), stubble height (3, 9, and 15 cm), and their interaction on grassland community characteristics and forage yield and quality in a grassland of Hulun Buir from 2019 to 2021. The results showed that late mowing and low stubble-height mowing significantly reduced community-level height and coverage in the next year. Low stubble-height mowing reduced community aboveground biomass in the following year, but the effect of mowing time was not significant. The relative biomass of grasses and sedges first increased and then decreased with the delay of mowing time, forbs showed an opposite pattern, and legumes showed no signi-ficant change. Low stubble-height mowing could enable higher hay yield in the same year, but resulted in substantial reduction in the next year. When mowing on August 30 with 3 cm high stubble left, the hay yield reached maximum value of 469 g·m^-2, which was 361.5% of the minimum value. The crude protein content of forage reached the maximum at the mowing time of August 30, which was higher than the minimum value by 6.5%, and the content was higher at high stubble-height mowing. The contents of acid and neutral detergent fiber increased gradually over the growing season, with those from mowing on September 9 being 8.0% and 5.9% higher than those from mowing on July 31 respectively, and were decreased with the increases of stubble height. We found that the reasonable mowing regime of Hulun Buir grassland as the mowing implemented from August 20 to 30 with about 9 cm high stubble left. Long-term mowing experiments are needed to draw a more reliable and objective conclusion.

Key words: Hulun Buir grassland, mowing time, stubble height, community characteristics, forage quality