混合放牧对荒漠草原群落生物量及地下净初级生产力的影响

Effects of mix-grazing on community biomass and belowground net primary productivity of desert steppe

为了研究内蒙古荒漠草原克氏针茅群落生物量对不同家畜组合的响应,试验以围封为对照,设置牛羊混牧、牛单牧和羊单牧三种放牧方式,于放牧2年后测定群落地上和地下生物量及相关群落特征指标。结果表明:整个生长季内(6—9月份),各处理群落地下生物量为(49.81±3.17)^(187.64±14.97)g/m^2;地下净初级生产力(BNPP)为(284.50±18.06)^(381.35±31.08)g/m^2。群落地上生物量于8月份达到最大值,地下生物量于9月份达到最大值。放牧降低了群落地上生物量但不同功能群生物量变化随草食家畜不同而有差异。牛单牧处理下群落生物量最小,可能与牛采食优势种羊草和克氏针茅等禾草有关,而羊单牧群落生物量和地下净生产力相对较大,可能和羊采食豆科和杂类草而较少采食优势种有关,牛羊混合放牧处理的生物量有介于牛单牧和羊单牧之间的趋势。说明结合生物量和BNPP的变化趋势,可初步判断牛羊混合放牧更有利于荒漠草原的高效和持久利用。

In order to study the response of Stipa krylovii community biomass to different livestock combinations in the desert steppe of Inner Mongolia,the experiment was conducted with enclosure as control,and set up three grazing modes(cattle and sheep mixed grazing,cattle sin-gle grazing,and sheep single grazing).The aboveground and underground biomass and related community characteristic indicators were meas-ured after grazing for 2 years.The results showed that the underground biomass of all treatment community ranged from(49.81±3.17)to(187.64±14.97)g/m2 during the entire growing season(from June to September),the belowground net primary productivity(BNPP)was between(284.50±18.06)and(381.35±31.08)g/m2.The aboveground biomass of community reached the maximum in August and the un-derground biomass of community reached the maximum in September.Grazing reduced the aboveground biomass of the community,but the bio-mass changes of different functional communities varied with different herbivore livestock.The community biomass under cattle single grazing treatment was the smallest,which may be related to the cattle eating grasses such as Leymus chinensis and Stipa krylovii.However,the communi-ty biomass and BNPP of sheep single grazing treatment were relatively large,which may be related to the fact that sheep mainly feed on legumes and weeds and less feed on dominant species.The community biomass of cattle and sheep mixed grazing was between cattle single grazing and sheep single grazing treatments.Based on the analysis of biomass and BNPP,it was concluded that the mixed grazing of cattle and sheep was more beneficial to efficient and sustainable utilization of desert steppe.