草地畜牧业的生态效益与经济效益协同以青海省玛多县为例

Synergy between ecological and economic benefits of grassland animal husbandry: Maduo County, Qinghai Province as an example

  • 摘要: 青海省草地资源丰富, 但受人口增长、气候变化等因素的影响, 草地面临大规模退化。受传统、文化、生态等因素影响, 高寒牧区牲畜出栏时间普遍较晚, 这种传统的畜牧业生产经营模式导致草地超载, 进一步加剧了草地退化。为探寻兼顾经济效益与生态效益的畜牧方案, 本研究以青海省果洛藏族自治州玛多县为例, 基于实地调研收集的2012—2021年畜牧业统计数据与牧户信息, 根据IPCC提供的家畜能量需求计算方法估算发现, 玛多县近10年畜牧业生产消耗的牧草量为44.30万t∙a−1, 与其草地生态承载量37.76万t∙a−1相比超载17.34%。其中, 由于牲畜出栏晚导致的牧草浪费达13.69万t∙a−1, 占牧草消耗量的30.90%。本研究进一步设置了“牲畜出栏量不变-提前出栏”和“牲畜存栏量不变-提前出栏”两种假设优化情景, 计算了不同优化情景下的牧草消耗量和肉产量。结果显示, 若提早牲畜出栏年龄, 可将玛多县平均草料转化率(即每万吨牧草干物质可生产的肉产量)较当前水平提高23%~86%; 同时, 在不超过草地生态承载力的前提下, 肉产品增产潜力相比当前水平最高可达58%, 可提高畜牧业产值6226万元。

     

    Abstract: Human activities and climate change pose increasing threats to the sustainability of the vast grasslands of Qinghai Province. Delayed slaughtering of livestock is common in alpine pastures because of the traditions and culture of the local people and ecological constraints, such as low temperatures. This traditional livestock husbandry system has led to grassland overload and subsequent degradation. Therefore, there is an urgent need to explore an optimal strategy for the development of livestock husbandry that accounts for both economic and ecological benefits. Maduo County, Guoluo Tibetan Autonomous Prefecture, Qinghai Province, is considered an example. Combining the statistics from the period of 2012−2021, the behavior data collected from field interviews with herdsmen, and the methodology in calculating energy and feed requirements from the IPCC Guidelines for national greenhouse gas inventories, we derived an annual grass biomass consumption of 4.430×105 t∙a−1 over the past ten years, with an overload rate of 17.34% compared to the carrying capacity of grassland ecosystem in Maduo County (3.776×105 t∙a−1). From the grass biomass consumption (i.e., 1.369×105 t∙a−1), 30.90% was forage waste caused by the herdsmen being “reluctant to sell” and delayed slaughtering. We further set up two optimal scenarios, “maintaining livestock slaughtering numbers at current level + accelerating slaughtering” and “maintaining livestock stocking numbers at current level + accelerating slaughtering”, to exploit the potential for increasing meat production. We found that if livestock were slaughtered or sold earlier, the production efficiency of animal husbandry in Maduo County could increase by 23%−86%. The potential to increase the yield of meat products could reach 58% with a livestock sector GDP increase of 62.26 million Yuan while grass forage consumption was still below the ecological carrying capacity. This study provides a pivotal case study that exploits potential ways to balance the ecological and economic benefits of alpine pasture systems.