春季休牧时长对锡林郭勒典型草原植被生产力和功能群的影响

Effects of Non-spring Grazing Duration on Vegetation Productivity and Functional Groups of Typical Grassland in Xilin Gol

春季休牧有助于放牧草场植被合理利用,但是休牧时长仍有待探讨。在锡林郭勒典型草原选取3块试验地,每块试验地设置休牧1个月(4月10日至5月10日休牧,参照当地现行政策)、休牧2个月(4月10日至6月10日休牧)以及全年休牧3个处理,于2019~2021年连续3年的8月中旬即植物生长旺季监测草地地上生物量、主要功能群和各等级牧草地上相对生物量。结果显示:2019~2021年,休牧2个月处理草地地上生物量显著高于休牧1个月处理(P<0.05);多年生禾草和优等牧草地上相对生物量较休牧1个月处理更高,且随休牧年限增加多年生禾草地上相对生物量呈增长趋势,而休牧1个月呈减少趋势。与全年休牧相比,休牧2个月处理2019年和2020年草地地上生物量显著较低(P<0.05),而在2021年两者无显著差异;与全年休牧相比,休牧2个月处理多年生禾草地上相对生物量更高,一、二年生植物地上相对生物量更低,优等牧草和良等牧草地上相对生物量更高且随休牧年限增加呈增加趋势,而全年休牧的低等牧草地上相对生物量在年际间呈显著增加趋势。从草地利用角度而言,春季休牧2个月比休牧1个月草地生产力更高,植物组成结构更为合理,更符合生产需求。

Non-spring grazing is helpful to the rational utilization of grazing grassland vegetation,but the duration remains to be discussed.In order to determine the appropriate non-spring grazing duration,three experimental plots were selected in the typical grassland in Xilinhot,each of which was divided into three treatment:one month off-grazing(from April 10 to May 10,according to the current local policies),two months off-grazing(from April 10 to June 10),and one year off-grazing.The aboveground biomass of grassland and relative biomass of different functional groups and grades of herbage were monitored in mid-August,the peak season of plant growth,for three consecutive years from^(2)019 tO_(2)021.The results showed that from^(2)019 tO_(2)021,the aboveground biomass in the 2-month off-grazing treatment was significantly higher than that in the 1-month off-grazing treatment(P<0.05).The aboveground relative biomass of perennial grasses and the aboveground biomass of superior herbage in the 2-month off-grazing were higher than those in the 1-month off-grazing treatment,and the aboveground biomass of perennial grasses increased with the increase of off-grazing years,while the aboveground biomass of gerennial grasses decreased with the 1-month off-grazing.Compared with the one-year off-grazing treatment,the aboveground biomass of grassland in the 2-month off-grazing treatment was significantly lower in 2019 and 2020(P<0.05),but there was no significant difference between the two treatments in 2021.Compared with the one-year off-grazing treatment,the 2-month off-grazing treatment had higher aboveground biomass of perennial grasses,lower aboveground biomass of one-year and biennial plants.Higher aboveground biomass of superior and fine grasses,and showed an increasing trend with the increase of off-grazing years,while the one-year off-grazing treatment had a dignificant increase in the aboveground biomass of lower grasses between years.From the perspective of grassland utilization,the grassland productivity of 2-month off-grazing in spring was higher than that of 1-month off-grazing,and the plant composition structure was more reasonable and more consistent with the actual production demand.