不同放牧强度对贵州威宁人工草地植被和土壤特性的影响

Effect of different grazing intensity on plantcommunity and soil property in cultivatedgrassland in Weining,Guizhou Province

摘要:

贵州威宁地区栽培草地的建植常以鸭茅(Dactylis glomerate)和白三叶(Trifolium repens)为主,通过在建植均匀的草地上进行分群分区放牧,研究了不同羊群的放牧强度对人工栽培草地植被和土壤特征的影响。结果表明:高强度放牧利用下的群落高度和地上生物量显著降低(P＜0.05),而低度和中度放牧处理下的群落高度和生物量均没有显著性变化(P＞0.05);放牧利用降低了鸭茅和白三叶的频度和盖度;放牧利用对表层土壤容重的影响不显著(P＞0.05),但是在高放牧压力处理中,10~30 cm土层土壤容重比其他处理平均升高32%;放牧对土壤化学性质有显著影响(P＜0.05),随着放牧强度的增加,土壤养分含量呈下降趋势。综合草产量和草地恢复能力分析,贵州威宁地区的栽培草地最适载畜量应该在17~23 SU/hm²。

Abstract:

The cultivated grassland is usually constructed with cocksfoot and white clover as the main species in Weining,Guizhou province.The grassland was divided into different zones for grazing,which explored effect of grazing intensity of different sheep groups on plant community and soil properties of cultivated grassland in the experiment.The results showed that the height of plant community and aboveground biomass were significantly decreased under the high grazing intensity (P＜0.05),while there were no significant differences on the height of plant community and aboveground biomass in medium and low grazing intensity groups,the frequency and coverage of cocksfoot and white clover were decreased by grazing.There was no significant differences by grazing on soil bulk in the topsoil layer.On the contrast,soil bulk in the 10~30 cm soil layer was 32% higher than other grazing intensity.There were significant differences (P＜0.05) on soil chemical properties by grazing intensity,with the increasing of grazing intensity,there was a decreasing trend on soil nutrient content.Regarding the grassland yield and restoring ability,the optimal capacity on livestock of cultivated grassland was 17~23 SU/hm2 in Weining,Guizhou province.