短花针茅草原划区牧试验研究

利用绵羊野外放牧试验，连续5a在内蒙古高原短花针茅草原研究划区轮牧和季节连续放牧对草地植被、土壤和家畜生产性能的影响，为草地合理利用提供理论依据。结果表明，划区轮牧有利于发挥绵羊的生产性能，在草地可利用牧草生物量供应短缺时，表现更为明显。在可利用牧草生物量供应十分充足的情况下，划区轮牧和季节连续放牧绵羊的生产性能比较接近。划区轮牧下绵羊发挥较高的生产性能是绵羊放牧行为、可利用牧草生物量、牧草营养物质含量、气象因子综合作用的结果，其中绵羊放牧行为格局的改变是最重要的。绵羊在轮牧小区内活动范围受到限制，游走时间大大减少，对牧草选择性采食明显降低，极大地提高了绵羊的采食效率和饲草的转化效率，并且绵羊消耗的能量也大为降低；草地可利用牧草生物量是草地放牧制度评价的可靠,当可利用牧草生物量低于24g/m^2时，划区轮牧优于季节连续放牧，而且绵羊的采食量受到明显影响，它能作为牧场确定绵羊冬季补饲育肥日期的有效参考指标，草地植被、土壤对放牧制度的反应不很敏感。划区轮牧和季节连续放牧区植被、土壤装况很接近，或轮牧稍好一些，在短期内变化不明显。

Experiment on Rotational Grazing System in Stipa breviflora Desert Steppe

The comparison of rotational and season-continuous grazing systems were conducted in Stipa breviflora desert steppe with sheep in five years and the characteristics of vegetation,soil,and livestock performance were measured in order to get the theoretical basis for the rational utilization of rangeland.The results showed that rotational grazing is benefit to the sheep production,especially in the situation of short of forage supply,the sheep production was similar in both grazing systems in the sufficient forage supply,the good sheep performance in rotational grazing system is due to the comprehensive effects of grazing behavior of sheep,forage biomass available,contents of nutrient matter of forage ,and the climate,but the change of pattem on grazing behavior of sheep is the most important factor.The idling time and grazing time in rotational grazing system were less than in season-continuous grazing system,which resulted in less selectivity of sheep for plant species,and higher transformation efficiency of sheep for forage in rotational grazing system than in season-continuous grazing system.Therefore,the liveweight of sheep in rotational grazing system was higher (P<0.05) than in season-continuous grazing system.Herbage biomass available of pasture is a useful index in the evaluation of grazing system.When the herbage biomass available was below 24g/m 2 the intake of sheep limited and rotational grazing system was benefit to sheep production.Vegetation and soil were not sense to grazing system in short period.