休牧对无芒雀麦改良草甸草原牧草生长速率及现存量和营养品质的影响

Effect of rest grazing on pasture growth rate,standingcrop and herbage quality of meadow steppeimproved with Bromus inermis

摘要:

休牧是提高草地可持续利用的重要方式。采用“放入-取出”的放牧率调控技术,以持续放牧作为对照,研究了早期休牧(6月15~7月15日休牧)、中期休牧(7月15~8月15日休牧)和晚期休牧(8月15~9月15日休牧)对呼伦贝尔改良草甸草原牧草生长速率,现存量和可提供牧草营养品质的影响,以探究何时休牧能够提高牧草生长速率,现存量和营养品质。结果表明:(1)牧草生长速率和可提供牧草的营养成分在休牧处理间差异不显著(P＞0.05),但早期和中期休牧的牧草现存量显著高于持续放牧(P＜0.01);(2)2016年牧草生长速率和营养成分均极显著低于2015年和2017年(P＜0.01);(3)年份和放牧时期的交互作用对牧草生长速率和营养成分有极显著地影响(P＜0.01),且牧草生长速率在放牧期间的变化是造成牧草营养成分变化的主要原因。总体而言,早期和中期休牧有利于提高牧草现存量,但牧草的生长速率和营养品质不受休牧时期的影响。

Abstract:

Rest grazing is an important grazing practice for improving the sustainable utilization of grassland.The impact of rest grazing on pasture growth rate,standing crop and herbage quality of meadow steppe improved with Bromus inermis was studied in Hulunbuir.By using "put and take stocking" method to regulate the stocking rate in experiment,the continuous grazing (control,CG) and 3 periodical rest grazing strategies,including rest grazing in early period (R1,no defoliation between 15th Jun.and 15th Jul.),rest grazing in middle period (R2,no defoliation between 15th Jul.and 15th Aug.) and rest grazing in late period (R3,no defoliation between 15th Aug.and 15th Sep.),were designed to explore the best rest grazing practice that could improve the pasture growth rate,standing crop and herbage quality.The results showed that 1) Grazing treatment had no significant influence on pasture growth rate and herbage quality (P＞0.05),but compared with CG,R1 and R2 could significantly increase standing crop (P＜0.01);2) Both pasture growth rate and herbage quality in 2016 were significantly (P＜0.01) lower than those in 2015 and 2017;3) Both pasture growth rate and herbage quality were significantly affected by the interaction of year and period (P＜0.01) and the variation of herbage quality was mainly caused by the pasture growth rate in grazing period.R1 and R2 benefited the standing crop,but the pasture growth rate and herbage quality was not affected by rest grazing period.