不同刈割频次对旱作混播人工草地群落特征的影响

Effects of Mowing Frequency on Community Characteristics of Dry Mixed Sowing Artificial Pasture

为了确定人工草地高效生产和稳定持续利用的最佳方案,于2002~2017年8月中旬(生物量高峰期)刈割前进行刈割频次对羊草(Leymus chinensis)+草原2号杂花苜蓿(Medicago varia Marein. cv. Caoyuan No.2)+无芒雀麦(Bromus inermis)混播旱作人工草地群落特征影响的研究。16年连续刈割划分为刈割前期(第1~5年)、中期(第6~11年)和后期(第12~16年)。结果表明:(1)随着刈割频次的增加,3种牧草的平均高度、总密度和总地上生物量均降低(不含一年刈割一次);其中,在刈割前期和中期对刈割响应不明显,且有所滞后,在刈割后期响应较为明显。(2)长期刈割使人工草地的地上生物量占比发生明显改变。在刈割前期,各刈割频次下3种牧草的总地上生物量占比差异不明显;从刈割中期开始,3种牧草的总地上生物量占比呈随刈割频次增加而降低的趋势(不含一年刈割一次)。(3)在内蒙古半干旱区羊草+草原2号杂花苜蓿+无芒雀麦混播旱作人工草地的长期刈割利用以一年刈割一次为宜。

The effects of mowing frequency on community characteristics of artificial pasture were explored to determine the best scheme for the efficient production and sustainable utilization of dry mixed sowing artificial pasture(Leymus chinensis+Medicago varia Marein.cv.Caoyuan No.2+Bromus inermis).The 16 years of continuous mowing were divided into three stages,including early mowing stage(1st~5th year),middle mowing stage(6th~11th year)and late mowing stage(12th~16th year).The results showed that with the increase of mowing frequency,the average plant height and total density,and total aboveground biomass of the three forages were decreased(excluding mowing once a year).Among three stages,the response to mowing was not significant or even lagged behind in the early and middle stages of mowing.While the response was more significant in the late stage of mowing.Furthermore,the aboveground biomass proportion of artificial grassland was significantly changed after long-term mowing.In the early stage of mowing,there was no significant difference in the proportion of aboveground biomass of the three forages under different mowing frequencies.From the middle stage of mowing,the proportion of total aboveground biomass of the three forages showed a trend of decreasing with the increase of mowing frequency(excluding mowing once a year).Lastly,in the semi-arid region of Inner Mongolia,it is advisable to mowing once a year for the long-term utilization of the dry acritical pasture mixed with Leymus chinensis+Medicago varia Marein.cv.Caoyuan No.2+Bromus inermis.