南方人工草地划区轮牧对产草量和绵羊体重的影响

Effect of rotation grazing on grass yield,weeds proportion and sheep body weight on sown grassland in South China

南方喀斯特地区放牧型人工草地开展划区轮牧,可有效地提高草地利用率且获得较高的放牧收益。确定科学的划区轮牧方案对于延长草地利用年限、降低杂草比例以及家畜增重等具有重要意义。本研究选择贵州灼圃多年生禾草/白三叶混播草地,以当地自由放牧为对照,开展了不同绵羊数量、放牧天数和轮牧频次对草地产草量、杂草比例和绵羊体重影响研究。2年试验结果显示,1)以草地总生物量、再生量、可食牧草生物量和禾豆比例为评价指标,6只绵羊,每个轮牧小区平均放牧12 d,轮牧频次3次效果最佳;2)以控制杂草生物量和杂草频度为评价指标,10只绵羊,每个轮牧小区平均放牧9 d,轮牧频次3次效果最佳;3)以绵羊月增重为评价指标,6只绵羊,每个轮牧小区平均放牧12 d,轮牧频次3次效果最佳。综合考虑划区轮牧对草地生产力、杂草控制和绵羊增重的影响,南方喀斯特地区禾草/白三叶混播人工草地建植初期实行划区轮牧以6只绵羊,每个轮牧小区放牧12 d,轮牧频次3次效果最佳。

Rotational grazing in the Karst area of South China can effectively improve the utilization rate of grass⁃land and obtain higher economical grazing returns.Making a scientific rotation grazing plan is very important to lengthening the years of grassland use,reducing the proportion of weeds and increasing the weight of livestock.In this study,the effects of different number of sheep,grazing days and rotational grazing frequency on grass yield,weed proportion and body weight of sheep were investigated by selecting the mixed perennial grass/white clover grassland in Zhuopu,Guizhou Province and taking local free grazing as a control.The results of the 2⁃year experi⁃ment showed that:1)using total grassland biomass,regeneration grass yield,edible forage biomass and the propor⁃tion of grass and bean as evaluation indexes,the rotation plan in which,six sheep averagely grazed for twelve days in each paddock and the rotation frequency was three times,was optimum;2)with weed biomass control and weed fre⁃quency as evaluation indexes,the rotation plan that ten sheep averagely grazed for nine days in each paddock and the rotation frequency was three times was the best;3)with the monthly weight gain of sheep as the evaluation index,the rotation plan that six sheep averagely grazed for twelve days in each paddock and the rotation frequency was three times was the best.Integrated considering the effects of rotation grazing on grassland productivity,weeds control and body weight gain of sheep,the study suggested that six sheep averagely grazed for twelve days in each paddock in the initial period of grass/white clover mixed artificial grassland in the Karst area of South China,and the frequency of ro⁃tational grazing was 3 times.