关键词: 干旱区, 水源点, 放牧梯度, 水源圈模型, 水稻, 分蘖期, 涝灾, 品种类型, 损失率

Abstract: On the grassland of arid and semiarid regions, livestock due to its water demand often concentrated at the vicinity of water point. The intensive grazing and trampling of the livestock often result in the radial degradation of grassland ecosystem along a gradient from the water point, and the formation of piosphere. According to the impacting degree of the grazing and trampling, piosphere can be divided into three concentric zones, i.e., sacrificial” core, transitional zone, and peripheral zone, radiating outward from the water point. Accordingly, the responses of vegetation and soil within the piosphere also exhibit a radial gradient from the water point to the margin. Piosphere provides an ideal context for the studies on the impact patterns of grazing on vegetation and soil, and the countermeasures for the conservation and sustainable utilization of natural resources in a degrading area because of the existence of an impacting gradient of grazing and trampling from the core to its peripheral zone.  This paper tried to provide a full picture about the concepts, approaches, and research progress of piosphere, aimed to benefit the efficient management and sustainable utilization of natural resources of grassland in arid and semiarid regions.

Key words: arid area, water point, grazing gradient, piosphere model, rice, tillering stage, submergence stress, variety type, loss rate.