火烧及微地貌对高原湿草甸优势种华扁穗草地上部灰分含量及热值的影响

Effects of burning and micro-geomorphology on ash content and caloric value of above-ground part of dominant species Blysmus sinocompressus in plateau wet meadow

为探讨火烧干扰以及微地貌差异对高原湿草甸植被的影响,以高原湿草甸优势种华扁穗草(Blysmus sinocompressus Tang et F.T.Wang)为研究对象,分别在经历火烧干扰和未烧的湿地中选择平地和地垄作为样地,研究了不同生长期以及不同年份华扁穗草地上部的灰分含量和热值(包括干质量热值和去灰分热值)变化。结果表明:在火烧平地、火烧地垄、未烧平地和未烧地垄4类样地中,不同生长期以及不同年份间华扁穗草地上部的灰分含量和热值均有一定差异。在火烧平地、火烧地垄和未烧平地3类样地中,与生长初期相比,生长旺盛期华扁穗草地上部的灰分含量均降低,其干质量热值和去灰分热值均升高;而在未烧地垄样地中,与生长初期相比,生长旺盛期华扁穗草地上部的灰分含量显著升高,其干质量热值和去灰分热值则均略降低。从样地类型看,在生长旺盛期,平地样地中华扁穗草地上部的灰分含量均低于地垄样地,其干质量热值和去灰分热值均高于地垄样地,其中,其灰分含量在火烧平地样地中最低、在未烧地垄样地中最高;其干质量热值和去灰分热值在火烧地垄样地中均最低、在未烧平地样地中均最高,但总体无显著差异。随时间推移,火烧样地特别是火烧平地样地中华扁穗草地上部的灰分含量增加,而其干质量热值和去灰分热值则有所降低但总体上与未烧样地间无显著差异。总体上看,在火烧样地中,华扁穗草地上部的干质量热值和去灰分热值低于未烧样地;而在平地样地中,其干质量热值和去灰分热值高于地垄样地。研究结果显示:火烧干扰和微地貌差异对华扁穗草地上部的灰分含量和热值均有一定的影响,据此,建议将植物地上部的灰分含量和热值作为高原湿草甸植被优势种响应环境扰动的参考指标。

In order to discuss effects of differences in burning interference and microgeomorphology on vegetation in plateau wet meadow, taking dominant species Blysmus sinocompressus Tang et F. T. Wang in plateau wet meadow as research object, ground and ridge in wetland experienced burning interference or not were selected as plot, respectively, and changes in ash content and caloric value (including gross caloric value and ash free caloric value) of aboveground part of B. sinocompressus in different growthperiods and years were researched. The results show that in four types of plots of burned ground, burned ridge, unburned ground and unburned ridge, there are a certain differences in ash content and caloric plots of burned ground, burned ridge and unburned ground, compared with early growth period, ashcontent in above鄄ground part of B. sinocompressus in vigorous growth period decreases, while both itsgross caloric value and ash free caloric value increase. While in unburned ridge plot, compared withearly growth period, ash content in above鄄ground part of B. sinocompressus in vigorous growth periodincreases significantly, while both its gross caloric value and its ash free caloric value decrease slightly.Based on plot type, ash content in above鄄ground part of B. sinocompressus in ground plot in vigorousgrowth period is lower than that in ridge plot, both its gross caloric value and its ash free caloric value arehigher than those in ridge plot, in which, its ash content is the lowest in burned ground plot and is thehighest in unburned ridge plot, and its gross caloric value and ash free caloric value are the lowest inburned ridge plot and are the highest in unburned ground plot, but there is no significant differencebetween them generally. With prolonging of time, ash content in aboveground part of B. sinocompressusin burned plot, especially in burned ground plot increases, while its gross caloric value and ash freecaloric value decrease but there is no significant difference with unburned plot generally. On the whole,gross caloric value and ash free caloric value of aboveground part of B. sinocompressus in burned plot arelower than those in unburned plot, while those in ground plot are higher than those in ridge plot. It issuggested that there are a certain effects of differences in burning interference and microgeomorphologyon ash content and caloric value of aboveground part of B. sinocompressus, hereby, ash content andcaloric value of aboveground part of plant are suggested as reference in vegetation responding to environmental disturbance in plateau wet meadow.