放牧对松嫩平原农牧交错区防护林下草地的影响

针对当前防护林草地已成为松嫩平原农牧交错区牲畜主要放牧场的实际情况，分析了不同放牧强度对防护林草地的影响．结果表明，未放牧防护林草地严重退化，与极度放牧防护林草地最为相似．未放牧和极度放牧均抑制了防护林草地的生长，轻度放牧和中度放牧却促进了防护林草地的生长，草地产量和质量均明显提高，并合理地利用了杨树叶资源．未放牧防护林草地质量指数仅为15．51。属严重退化草地范畴；轻度放牧草地质量指数为86．4，随着放牧强度的增加，草地质量逐渐下降．因此，应提倡轻度放牧、中度放牧，防止未放牧和极度放牧现象出现，促进防护林草地生长，并充分利用杨树叶资源增加畜牧业牧草的来源．

Effect of grazing on grassland under protective plantation in the ecotone between agriculture and animal husbandry of Songnen plain

Based on the current special position that grassland under protective plantation is one of the most important grazing spaces of the ecotone between agriculture and animal husbandry in Songnen plain,an experiment was conducted to investigate the effect of grazing on grassland under protective plantation.The results showed that no-grazing grassland in the grassland under protective plantation was seriously degenerated,but light and moderate grazing could stimulate the growth of grass and the product and quality of grassland.The index of grassland quality(IGQ) of no-grazing grassland was the lowest(15.51),attributing to serious degradation,while that of light grazing grassland was the highest(86.41),and the IGQ was decreased with increasing grazing intensity.Therefore,in order to stimulate the grass growth of the grassland,fully utilize the leaves of poplar,and increase the available forage resources,light and moderate grazing intensity should be advocated,but no-grazing and extreme grazing should be avoided.