Climate warming and livestock grazing are known to have great influences on alpine ecosystems like those of the Qinghai-Tibetan Plateau （QTP） in China. However, it is lacking of studies on the effects of warming and...Climate warming and livestock grazing are known to have great influences on alpine ecosystems like those of the Qinghai-Tibetan Plateau （QTP） in China. However, it is lacking of studies on the effects of warming and grazing on plant and soil properties in these alpine ecosystems. In this study, we reported the related research from manipulative experiment in 2010-2012 in the QTP. The aim of this study was to investigate the individual and combined effects of warming and clipping on plant and soil properties in the alpine meadow ecosystem. Infrared radiators were used to simulate climate warming starting in July 2010, while clipping was performed once in Octo- ber 2011 to simulate the local livestock grazing. The experiment was designed as a randomized block consisting of five replications and four treatments： control （CK）, warming （W）, clipping （C） and warming＋clipping combination （WC）. The plant and soil properties were investigated in the growing season of the alpine meadow in 2012. The results showed that W and WC treatments significantly decreased relative humidity at 20-cm height above ground as well as significantly increases air temperature at the same height, surface temperature, and soil temperature at the depth of 0-30 cm. However, the C treatment did not significantly decrease soil moisture and soil temperature at the depth of 0-60 cm. Relative to CK, vegetation height and species number increased significantly in W and WC treatment, respectively, while vegetation aboveground biomass decreased significantly in C treatment in the early growing season. However, vegetation cover, species diversity, belowground biomass and soil properties at the depth of 0-30 cm did not differ significantly in W, C and WC treatments. Soil moisture increased at the depth of 40-100 cm in W and WC treatments, while belowground biomass, soil activated carbon, organic carbon and total nitrogen increased in the 30-50 cm soil layer in W, C and WC treatments. Although the initial responses of plant and soil properties to experimental warming and clipping were slow and weak, the drought induced by the down- ward shift of soil moisture in the upper soil layers may induce plant belowground biomass to transfer to the deeper soil layers. This movement would modify the distributions of soil activated carbon, organic carbon and total nitrogen However, long-term data collection is needed to further explain this interesting phenomenon.展开更多
Climate warming may promote soil organic carbon(SOC)decomposition and alter SOC stocks in terrestrial ecosystems,which would in turn affect climate warming.We manipulated a warming experiment using open-top chambers t...Climate warming may promote soil organic carbon(SOC)decomposition and alter SOC stocks in terrestrial ecosystems,which would in turn affect climate warming.We manipulated a warming experiment using open-top chambers to investigate the effect of warming on SOC stock and chemical composition in an alpine peatland in Zoigêon the eastern Tibetan Plateau,China.Results showed that 5 years of warming soil temperatures enhanced ecosystem respiration during the growing season,promoted above-and belowground plant biomass,but did not alter the SOC stock.However,labile O-alkyl C and relatively recalcitrant aromatic C contents decreased,and alkyl C content increased.Warming also increased the amount of SOC stored in the silt-clay fraction(<0.053 mm),but this was offset by warming-induced decreases in the SOC stored within micro-and macroaggregates(0.053–0.25 and>0.25 mm,respectively).These changes in labile and recalcitrant C were largely associated with warming-induced increases in soil microbial biomass C,fungal diversity,enzyme activity,and functional gene abundance related to the decomposition of labile and recalcitrant C compounds.The warming-induced accumulation of SOC stored in the silt-clay fraction could increase SOC persistence in alpine peatland ecosystems.Our findings suggest that mechanisms mediated by soil microbes account for the changes in SOC chemical composition and SOC in different aggregate size fractions,which is of great significance when evaluating SOC stability under climate warming conditions.展开更多
There has been an obvious diurnal asymmetrical warming effect as a result of the overall climate warming in the Tibetan Plateau.To reduce the uncertainty caused by the diurnal asymmetrical warming effect on future foo...There has been an obvious diurnal asymmetrical warming effect as a result of the overall climate warming in the Tibetan Plateau.To reduce the uncertainty caused by the diurnal asymmetrical warming effect on future food security predictions in the Tibetan Plateau,this study used winter highland barley(var.Dongqing No.1)for the experimental materials,and the FATI(Free Air Temperature Increase)field open heating system to carry out a simulated diurnal asymmetrical warming experiment(AW:All-day warming,DW:Daytime warming,NW:Nighttime warming,CK:Control)for two growing seasons(2018-2019 and 2019-2020)at the Lhasa Agroecosystem Research Station.The growth characteristics and yield of Tibetan winter highland barley were investigated in this study.Compared to the control,all the AW,DW and NW treatments had significant effects on the phenological period of winter highland barley,with the advancement of the phenological phase and shortening of the whole growth period.The degree of influence was AW>NW>DW,and all the AW,DW and NW treatments shortened the interval from sowing to heading of winter highland barley and increased the interval from heading to maturity.The effect on the phenological phase was the most obvious for AW and reached a statistically significant level(P<0.05).During the generative growth phase,the biomass above-ground and plant height of winter highland barley had an increasing tendency under the different warming conditions.In the late growth period,the biomass above-ground and plant height of the NW treatment were significantly higher than those of the other treatments.In addition,the warming caused a decrease in the dry matter distribution proportions of leaves and stems at the mature stage,and an increase in the distribution ratios of roots and spikes;and the AW,NW and DW treatments increased grain yields by 16.4%,24.6%and 9.5%,respectively,on average in the two years.The increasing effect on grain yields of the NW treatment reached a significant level compared with the control in 2019-2020(t=-2.541,P=0.026).In terms of yield composition,the effective spike number and 1000-grain weight tended to increase.The grain number per spike tended to increase,except for the AW treatment,while panicle length and seed setting rate tended to decrease,except for the NW treatment.Therefore,the effects of different simulated diurnal asymmetrical warming treatments on the growth characteristics and yield of winter highland barley were variable in the Tibetan Plateau.展开更多
基金financially supported by the Hundred Talent Program of Chinese Academy of Sciences and the National Natural Science Foundation of China (41301211, 41201195)
文摘Climate warming and livestock grazing are known to have great influences on alpine ecosystems like those of the Qinghai-Tibetan Plateau （QTP） in China. However, it is lacking of studies on the effects of warming and grazing on plant and soil properties in these alpine ecosystems. In this study, we reported the related research from manipulative experiment in 2010-2012 in the QTP. The aim of this study was to investigate the individual and combined effects of warming and clipping on plant and soil properties in the alpine meadow ecosystem. Infrared radiators were used to simulate climate warming starting in July 2010, while clipping was performed once in Octo- ber 2011 to simulate the local livestock grazing. The experiment was designed as a randomized block consisting of five replications and four treatments： control （CK）, warming （W）, clipping （C） and warming＋clipping combination （WC）. The plant and soil properties were investigated in the growing season of the alpine meadow in 2012. The results showed that W and WC treatments significantly decreased relative humidity at 20-cm height above ground as well as significantly increases air temperature at the same height, surface temperature, and soil temperature at the depth of 0-30 cm. However, the C treatment did not significantly decrease soil moisture and soil temperature at the depth of 0-60 cm. Relative to CK, vegetation height and species number increased significantly in W and WC treatment, respectively, while vegetation aboveground biomass decreased significantly in C treatment in the early growing season. However, vegetation cover, species diversity, belowground biomass and soil properties at the depth of 0-30 cm did not differ significantly in W, C and WC treatments. Soil moisture increased at the depth of 40-100 cm in W and WC treatments, while belowground biomass, soil activated carbon, organic carbon and total nitrogen increased in the 30-50 cm soil layer in W, C and WC treatments. Although the initial responses of plant and soil properties to experimental warming and clipping were slow and weak, the drought induced by the down- ward shift of soil moisture in the upper soil layers may induce plant belowground biomass to transfer to the deeper soil layers. This movement would modify the distributions of soil activated carbon, organic carbon and total nitrogen However, long-term data collection is needed to further explain this interesting phenomenon.
基金supported by the National Natural Science Foundation of China(Nos.41971024 and 41373069)。
文摘Climate warming may promote soil organic carbon(SOC)decomposition and alter SOC stocks in terrestrial ecosystems,which would in turn affect climate warming.We manipulated a warming experiment using open-top chambers to investigate the effect of warming on SOC stock and chemical composition in an alpine peatland in Zoigêon the eastern Tibetan Plateau,China.Results showed that 5 years of warming soil temperatures enhanced ecosystem respiration during the growing season,promoted above-and belowground plant biomass,but did not alter the SOC stock.However,labile O-alkyl C and relatively recalcitrant aromatic C contents decreased,and alkyl C content increased.Warming also increased the amount of SOC stored in the silt-clay fraction(<0.053 mm),but this was offset by warming-induced decreases in the SOC stored within micro-and macroaggregates(0.053–0.25 and>0.25 mm,respectively).These changes in labile and recalcitrant C were largely associated with warming-induced increases in soil microbial biomass C,fungal diversity,enzyme activity,and functional gene abundance related to the decomposition of labile and recalcitrant C compounds.The warming-induced accumulation of SOC stored in the silt-clay fraction could increase SOC persistence in alpine peatland ecosystems.Our findings suggest that mechanisms mediated by soil microbes account for the changes in SOC chemical composition and SOC in different aggregate size fractions,which is of great significance when evaluating SOC stability under climate warming conditions.
基金The Natural Science Foundation of China(31370458)The Science and Technology Service Network Project of Chinese Academy of Sciences(KFJ-STS-QYZD-117)+1 种基金The Local Project Guided by the Central Government(YDZX20195400004717)The Key Project of Dazi District of Xizang Autonomous Region(XZDZKJ-2021-01)。
文摘There has been an obvious diurnal asymmetrical warming effect as a result of the overall climate warming in the Tibetan Plateau.To reduce the uncertainty caused by the diurnal asymmetrical warming effect on future food security predictions in the Tibetan Plateau,this study used winter highland barley(var.Dongqing No.1)for the experimental materials,and the FATI(Free Air Temperature Increase)field open heating system to carry out a simulated diurnal asymmetrical warming experiment(AW:All-day warming,DW:Daytime warming,NW:Nighttime warming,CK:Control)for two growing seasons(2018-2019 and 2019-2020)at the Lhasa Agroecosystem Research Station.The growth characteristics and yield of Tibetan winter highland barley were investigated in this study.Compared to the control,all the AW,DW and NW treatments had significant effects on the phenological period of winter highland barley,with the advancement of the phenological phase and shortening of the whole growth period.The degree of influence was AW>NW>DW,and all the AW,DW and NW treatments shortened the interval from sowing to heading of winter highland barley and increased the interval from heading to maturity.The effect on the phenological phase was the most obvious for AW and reached a statistically significant level(P<0.05).During the generative growth phase,the biomass above-ground and plant height of winter highland barley had an increasing tendency under the different warming conditions.In the late growth period,the biomass above-ground and plant height of the NW treatment were significantly higher than those of the other treatments.In addition,the warming caused a decrease in the dry matter distribution proportions of leaves and stems at the mature stage,and an increase in the distribution ratios of roots and spikes;and the AW,NW and DW treatments increased grain yields by 16.4%,24.6%and 9.5%,respectively,on average in the two years.The increasing effect on grain yields of the NW treatment reached a significant level compared with the control in 2019-2020(t=-2.541,P=0.026).In terms of yield composition,the effective spike number and 1000-grain weight tended to increase.The grain number per spike tended to increase,except for the AW treatment,while panicle length and seed setting rate tended to decrease,except for the NW treatment.Therefore,the effects of different simulated diurnal asymmetrical warming treatments on the growth characteristics and yield of winter highland barley were variable in the Tibetan Plateau.
