刈割留茬高度对大针茅草原群落生物量的影响

Effects of Stubble Height on Biomass of Stipa grandis Steppe Community

于2015~2018年8月生物量高峰期在内蒙古锡林浩特市毛登牧场大针茅草原进行野外刈割并取样,设置轻度刈割(LM,留茬8cm)、中度刈割(MM,留茬5cm)及重度刈割(HM,留茬2cm)3个留茬高度,以围封(CK)为对照,通过对各处理草地群落地上生物量、地下生物量和总生物量的测定及根冠比的计算,探讨不同留茬高度对草地的影响。结果表明:随着留茬高度降低、强度增大,地上及地下生物量均呈下降趋势;与CK相比,地上生物量显著降低(P<0.05),对刈割响应迅速,而地下生物量则降低不显著,响应迟缓,有所滞后。与CK相比,轻度刈割下,地上生物量有所降低,但地下生物量及总生物量有所增加;中度及重度刈割下,地上生物量显著降低(P<0.05),地下生物量及总生物量有所降低。其次,随着刈割强度增大,群落根冠比有增加趋势。

The study was conducted to determine the effects of stubble height on above-and underground biomass and its relationship during the peak of biomass form August 2015 to August 2018 on Stipa grandis steppe in Maoden Ranch,Xilinhot city,Inner Mongolia.The experiment was carried out with light mowing (LM:stubble 8cm),moderate mowing (MM:stubble 5cm) and severe mowing (HM:stubble 2cm) three stubble heights,with enclosure (CK) as control.The aboveground biomass,underground biomass and total biomass measurement were measured and the root shoot ratio was calculated.The results showed that the above-and underground biomass decreased with the decrease of the stubble height and intensity.Compared with CK,the aboveground biomass decreased significantly (P<0.05),and the response to mowing was rapid,while the underground biomass decreased insignificantly,response slowly and lagged behind.The aboveground biomass decreased with LM treatment,but the underground biomass and total biomass increased.Under MM and HM treatment,the aboveground biomass decreased significantly (P<0.05),and the underground biomass and total biomass decreased.Secondly,with the increase of mowing intensity,the root shoot ratio of the community tended to increase.