祁连山北坡3个季节性牧场夏季的土壤呼吸

2017-09-08 03:40郭雅蓉侯扶江于应文
草业科学 2017年8期
关键词:盖度土壤温度牧场

郭雅蓉,侯扶江,于应文

(1.草地农业生态系统国家重点实验室,兰州大学草地农业科技学院,甘肃 兰州 730020; 2.农业部草牧业创新重点实验室,甘肃 兰州 730020)

祁连山北坡3个季节性牧场夏季的土壤呼吸

郭雅蓉1,2,侯扶江1,2,于应文1,2

(1.草地农业生态系统国家重点实验室,兰州大学草地农业科技学院,甘肃 兰州 730020; 2.农业部草牧业创新重点实验室,甘肃 兰州 730020)

以祁连山北坡高寒灌丛化草甸和高寒草原为对象,测定比较夏季、冬季和春秋季牧场的夏季土壤呼吸特征及与其影响因素之间的关系,为牧场碳汇管理提供依据。以高山灌丛化草甸为主的夏季牧场日均土壤呼吸速率(Rs)为0.26 μmol·(m2·s)-1,以高寒草原为主的冬季和春秋季牧场日均Rs分别为0.24和0.19 μmol·(m2·s)-1。随放牧增强,冬季牧场Rs减小,春秋季和夏季牧场Rs增加。冬季牧场Rs与土壤含水量(soil mosture,SM)显著正相关(P<0.05),Rs与放牧率(stocking rate,SR)和土壤温度(soil temperature,Ts)显著负相关(P<0.05);春秋季牧场Rs与SR、光合有效辐射(photosynthetically awailable radiation,PAR)、Ts显著正相关(P<0.05);春秋季牧场Rs与SM和群落盖度(community coverage,C)显著负相关(P<0.05)。结构模型方程表明,冬季牧场放牧率通过Ts对Rs的负向间接作用最强,SM对Rs正向的直接作用次之;春秋季牧场群落盖度对Rs负向直接作用最大,放牧率对Rs正向的直接作用次之。冬季牧场Rs可分别由Rs=0.436-0.012Ts+0.018SM(R2=0.911,P=0.038)和Rs=0.707+0.002SR-0.02Ts(R2=0.775,P=0.037) 估测;春秋季牧场可由Rs=-0.239+0.003PAR-0.001C(R2=0.979,P=0.004)估测。

放牧;高寒草原;高寒灌丛草甸;土壤呼吸;土壤温度;土壤水分;光合有效辐射

土壤呼吸是其产生CO2的代谢过程,是自养(根)和异养呼吸(土壤微生物)的总和[1]。陆地生态系统2/3的碳储存在土壤中[2],土壤呼吸是一种重要的碳交换过程,是土壤向大气输出碳的主要途径[3],受土壤物理、化学和生物等因素的综合影响[4]。草地生态系统作为世界面积最大的陆地生态系统,其土壤呼吸对调节全球碳循环具有重大作用[5],对土壤有机质的矿化、异养代谢、土壤腐殖质和枯落物碳代谢、草地地下碳分配和生产力等有重要指示作用[6]。

土地利用方式显著影响草地生态系统土壤有机碳的贮存和释放[7],而且是导致大气CO2浓度升高的重要原因之一[1]。放牧通过家畜采食、践踏和排泄粪便对土壤呼吸产生直接和间接作用[7]。家畜采食降低植被盖度和高度,提高太阳透射率,导致地表升温、蒸发增加,促进土壤呼吸[8]。高强度践踏改变土壤紧实度、渗透率和透气性等物理结构以及生物土壤结皮、土壤微生物活性等,导致土壤呼吸强度减弱[9-10]。家畜排泄改善草地养分,影响土壤微生物活性和根系代谢,从而加快生态物质循环和能量流动,进而促进土壤呼吸[11]。适度放牧促进草地生物量、根系和凋落物数量、土壤动物和微生物多样性的提高,从而增强土壤呼吸;不合理的放牧导致草地植被稀疏,草地生物量下降,从而降低土壤呼吸速率[12-13]。青藏高原高山草甸的放牧强度降低约50%,土壤释放的CO2大约翻一翻[14]。新疆天山高寒草原短期禁牧,土壤CO2和N2O排放与长期禁牧和自由放牧差异不显著[15]。

国内外放牧强度对土壤呼吸的影响研究很多[2-3,16-29],但在牧场尺度上,放牧季节对草原土壤呼吸的影响报道较少,且放牧强度多以定性的过牧或重牧、中牧、轻牧、禁牧或围封等为主,而放牧强度与土壤呼吸之间的定量关系尚不明确。国内对于高寒草甸研究较多[15,23,29-31],但对高寒灌丛化研究较少。为此,研究祁连山北坡不同季节牧场土壤呼吸特征及与影响土壤呼吸因素之间的相互关系,并建立预测模型,为牧场碳汇管理提供理论依据,还可为牧场科学管理决策提供理论支持。

1 材料与方法

1.1 研究区概况

研究区位于甘肃省肃南裕固族自治县甘肃马鹿(Cervuselaphuskansuensis)养殖场,有3个季节牧场,地处祁连山中段北麓,地理坐标38.8° N、99.6° E附近,平均海拔2 850 m。年均温3.6 ℃,年均降水量253.0 mm,主要集中在6月-9月。牧草一般4月下旬返青,7月上旬进入生长旺盛期,9月上旬开始枯黄[19]。

1.2 样地设置

试验设在甘肃马鹿的冬季牧场(winter pasture,WP)、春秋季牧场(spring-autumn pasture,SAP)和夏季牧场(summer pasture,SP)。根据草原综合顺序分类法[32],冬季和春秋季牧场属于寒温微干山地草原类,土壤为山地栗钙土[33];夏季牧场属于亚高山灌丛草甸,土壤属于高山灌丛草甸土。冬季和春秋季牧场主要植物种为紫花针茅(Stipapurpurea)、短花针茅(S.breviflora)、扁穗冰草(Agropyroncristatum)、醉马草(Achnatheruminebrians)、冷蒿(Artemisiafrigida)、赖草(Leymussecalinus)、银灰旋花(Convolvulusammannii)和其它一些植物[9,34];夏季牧场主要植物种为鬼箭锦鸡儿(Caraganajubata);冬季牧场的醉马草、甘肃马先蒿(Pediculariskansuensis)、狼毒(Stellerachamaejasme)和银灰旋花等毒杂草分布广泛,在牧场入口附近甚至是优势种或次优势种,退化严重。醉马草仅分布在春秋季牧场入口附近,纵深区域较少,退化较轻;夏季牧场畜圈附近退化严重,醉马草为优势种[35]。

冬季和春秋季牧场沿马鹿采食的主要路线在距牧场入口0、300、600、900、1 200和1 500 m处共设6个样地,向外呈放射状形成放牧率由高到低的牧压梯度。1个家畜单位(animal unit,AU)为1头成年甘肃马鹿母鹿(活体重200 kg左右)带一只哺乳期的小鹿。依据家畜体量或采食量,将各年龄段马鹿换算为标准家畜单位[34,36-37]。放牧率以单位放牧地面积上家畜单位与放牧时间(月month,M)的乘积(AUM)表示,分别得到冬季和春秋季牧场的放牧率(表1)[34,36-37]。1999年夏季从放牧开始,直至放牧结束,每隔2 h观察一次马鹿的放牧行为,记录样地内马鹿数量和年龄。

冬季和春秋季牧场各样地放牧率(stocking rate,SR)计算公式:

式中:SRi为样地i的放牧率,SR为整个牧场的放牧率,Fi为家畜在样地i的出现频率,n为样地的总数[36-37]。

夏季牧场由南北走向的两个小山及其间谷地组成,距离畜圈50和600 m,分别在东西方向上设置两条样带,600 m样带位于50 m样带南侧,海拔较50 m样带高50 m左右。每条样带分为坡顶、坡中、坡谷;根据坡向分为阳坡和阴坡(表2)。

1.3 测定方法

应用CI-301PS闭路系统的CI-301SR土壤呼吸室测定土壤呼吸。冬季牧场,1999年7月06:00-21:00,每隔2 h测定一次,每样地每次随机选择5个样点,每样点测定5次,取平均值。春秋季牧场和夏季牧场,09:00-11:00测定一次,每样地随机布设5个样点,每样点测5个数据。同时测定气温、光照、土壤地表温度、土壤含水量等数据。

土壤呼吸速率计算公式:

Rs=12 323.35×V×P/Δt×Ta×A.

式中:Rs为土壤呼吸速率[μmol·(m2·s)-1],V为体积流速(L·min-1),P为大气压力(Pa),Δt为测定间隔时间(Δt=30 s),Ta为空气湿度(K),A为呼吸室面积(A=74.5 cm2)。

冬季牧场日均土壤呼吸速率:用测定的土壤呼吸速率对时间积分,取其时间平均值。

冬季和春季牧场在每个样地随机取5个(1 m×1 m)样方,统计每个样方中的植物种类,记录每个植物种的投影盖度,总盖度=各个植物种的分盖度之和。土样采集与群落盖度同步,每样地用直径5 cm土钻取15钻,0-40 cm深度每10 cm为一层,筛出根系,测定根系生物量[38]。

表1 祁连山北坡不同放牧率下冬季和春秋季牧场植物群落Table 1 Plant community in winter and spring-autumn pasture under different stocking rates on the northern slope of Qilian Mountains

表2 祁连山北坡夏季牧场不同坡位植物群落Table 2 Plant community on the different slope positions in summer pasture on the northern slope of Qilian Mountains

1.4 数据统计分析

用SPSS 20.0软件,对祁连山北坡夏季不同季节牧场影响土壤呼吸因子及其与土壤呼吸之间进行相关性分析;运用LSD法分别对夏季牧场相同距离不同坡位、不同距离相同坡位土壤呼吸进行多重比较;利用通径分析方法,分析影响土壤呼吸因子分别在冬季和春秋季牧场对土壤呼吸的直接和间接作用;采用多元回归方法,建立影响土壤呼吸因子与土壤呼吸之间的回归模型。用Microsoft Excel 2010软件绘图。

2 结果与分析

2.1 土壤呼吸特征

冬季牧场300 m样地土壤呼吸日动态具有代表性,基本呈单峰曲线变化,14:00左右最高(图1),与土壤温度变化一致。

随放牧率增加,冬季牧场日均土壤呼吸速率下降,春秋季牧场呈增加变化(图2)。放牧率增加1 AUM·hm-2,冬季和春秋季牧场土壤呼吸分别减少0.014 2 μmol·(m2·s)-1和增加0.025 7 μmol·(m2·s)-1。

图1 冬季牧场土壤呼吸和土壤温度日动态Fig. 1 Daily dynamics of soil respiration and soil temperature in winter pasture on the northern slope of Qilian Mountains

夏季牧场,相同坡位,离畜圈50 m的样地土壤呼吸速率高于离畜圈600 m的样地(P<0.05)(表3);相同距离不同坡位土壤呼吸不同。夏季牧场阴坡坡顶日均土壤呼吸速率[Rs=0.318μmol·(m2·s)-1]>坡谷[Rs=0.214 μmol·(m2·s)-1]>坡中[Rs=0.165 μmol·(m2·s)-1],阳坡坡中日均土壤呼吸速率[Rs=0.308 μmol·(m2·s)-1]>坡顶[Rs=0.243 μmol·(m2·s)-1]>坡谷[Rs=0.214 μmol·(m2·s)-1]。

图2 冬季牧场和春季牧场放牧率与土壤呼吸速率的关系Fig. 2 The relationship between stocking rate and soil respiration in winter and spring-autumn pasture on the northern slope of Qilian Mountains

2.2 影响土壤呼吸的因素分析

冬季牧场土壤呼吸速率与放牧率、土壤含水量和土壤温度显著相关(P<0.05)(表4),放牧率与土壤0-10 cm温度显著负相关(P<0.05);冬季牧场土壤呼吸速率与其含水量显著正相关(P<0.05),与放牧率和土壤温度显著正相关(P<0.05)。

影响春秋季牧场土壤呼吸的因素较多,放牧率、光合有效辐射和土壤温度与土壤呼吸显著正相关(P<0.05),土壤含水量、群落盖度与土壤呼吸显著负相关(P<0.05)。

冬季牧场土壤呼吸通径分析显示(图3),土壤含水量和温度对冬季牧场土壤呼吸是直接作用,放牧对土壤呼吸是间接作用,土壤温度相较于土壤含水量对土壤呼吸的直接作用较大,说明冬季牧场日均土壤呼吸速率土壤0-10 cm温度变化较敏感。放牧主要通过改变土壤0-10 cm温度间接影响冬季牧场土壤呼吸。

表3 祁连山北坡夏季牧场不同坡位土壤呼吸速率Table 3 Soil respiration on the different slope positions in summer pasture on the northern slope of Qilian Mountains

注:不同小写字母表示相同距离不同坡位之间差异显著(P<0.05);不同大写字母表示相同坡位不同距离之间差异显著(P<0.05)。

Note: Different lowercase letters within the same distance indicate significant difference between different slope positions at the 0.05 level; different uppercase letters within the same slope position indicate significant difference between different distances at the 0.05 level.

通径分析显示,春秋季牧场放牧率、光合有效辐射、土壤温度、土壤含水量和群落盖度均对土壤呼吸产生直接作用,放牧率和光合有效辐射对土壤呼吸有间接作用(图4)。群落盖度对春秋季牧场的土壤呼吸的直接作用最大,放牧次之;光合有效辐射通过群落盖度对土壤呼吸的间接作用较大,放牧通过土壤含水量对土壤呼吸的间接作用极显著。可见,群落盖度是春秋季牧场土壤呼吸主要限制因子。

冬季牧场分别以放牧率和土壤温度、土壤温度和土壤含水量预测土壤呼吸的两个决定系数均在0.05水平上显著,说明冬季牧场土壤呼吸可由其与放牧率和土壤温度、土壤温度和土壤含水量之间的多元回归模型很好地预测(表5)。春秋季牧场光合有效辐射和群落盖度预测土壤呼吸的决定系数在0.01水平上显著,说明春秋季牧场土壤呼吸可由其与光合有效辐射和群落盖度之间的多元回归模型很好地预测。

表4 祁连山北坡冬季和春秋季牧场土壤呼吸影响因素之间的相关性分析Table 4 Correlation among the factors of affecting soil respiration in winter and spring-autumn pasture on the northern slope of Qilian Mountains

注:右上部分是春秋季牧场;左下部分是冬季牧场。SR,放牧率;PAR,光合有效辐射;Ts,土壤温度;SM,土壤含水量;C,群落盖度;UB,地下生物量;Rs,土壤呼吸速率。

Note: Upper right part, spring-autumn pasture; lower left part, winter pasture. SR, stocking rate; PAR, photosynthetically available radiation; Ts, soil temperatute; SM, soil moisture; C, community coverage; UB, underground biomass; Rs, soil respiration.

间接作用Indirecteffect作用值EstimateP放牧率通过土壤温度对土壤呼吸的作用EffectofSRonRsbyTs-0.92130.002

图3 祁连山北坡冬季牧场土壤呼吸通径分析
Fig. 3 The path analysis of soil respiration in winter pasture on the northern slope of Qilian Mountains

注:实线为直接影响。*, **, ***分别表示在0.05、0.01和0.001水平上显著。下图同。

Note: Solid lines indicate direct effects. *, **, and *** indicate significant relationship at 0.05, 0.01, and 0.001 levels, respectively. similarly for the Fig. 4.

3 讨论

冬季和春秋季牧场在夏季的土壤呼吸速率与放牧率变化趋势相反,可能由于冬季牧场放牧较重,破坏了土壤理化性状,一方面土壤水分和有机碳下降,抑制土壤微生物和根系活动[37-38],另一方面牧草地上部分光合物质同化下降,向根系物质运输减少,使根系活动减弱[33-34];春秋季牧场放牧较轻,家畜春季适度放牧减少了群落盖度,改善了群落微气候,到达地面的太阳辐射增强,土壤升温较快,土壤呼吸强度随之增大[39]。春秋季牧场土壤呼吸速率低于冬季牧场,表明其碳汇功能较强,可能与放牧强度较低有关。

从土壤呼吸速率、土壤含水量和土壤温度相关性来看,冬季牧场土壤呼吸速率与土壤温度显著负相关,与短花针茅荒漠草原不同放牧制度下土壤呼吸速率与土壤温度相关性[28]相同,而亚高山草甸在生长季节的土壤呼吸速率与土壤温度正相关[29],这可能是由于土壤呼吸受多种生物、非生物因素影响有关。一些研究表明,当土壤湿度成为冬季牧场限制因子时,土壤呼吸对温度的敏感性会降低[31,40];当土壤温度较低时,增加冠层盖度可提高土壤湿度,从而促进土壤呼吸[1]。虽然冬季和春秋季牧场的土壤含水量与土壤温度均呈负相关关系,但冬季牧场的相关性不显著,而春秋季牧场呈显著负相关关系;这可能是土壤呼吸在小尺度范围内受地形地貌[40]、植被[41]、土壤质地[42]以及土地利用方式[43]的影响,从而土壤呼吸表现出明显空间变化特征;另一方面,由于不同植物、群落、土壤微气候存在一定差异,而土壤温度和水分均可通过影响土壤中的微生物活性及植被根系生长直接影响土壤呼吸作用[44-45]。

在内蒙古短花针茅荒漠草原,放牧削弱了土壤水分对土壤呼吸速率的影响,可能是放牧样地由于牲畜的采食和踩踏,地上生物量和凋落物等减少,导致土壤表层温度易升高,土壤水分降低[46]。但本研究中,冬季牧场放牧促进土壤表层温度对土壤呼吸速率的影响,从而对土壤呼吸产生影响。

夏季牧场阴坡坡顶日均土壤呼吸速率大于坡谷大于坡中,阳坡坡顶日均土壤呼吸速率小于坡中但大于坡谷,这可能因为高寒灌丛草甸土壤水分充足,热量是土壤呼吸的限制因子,放牧强度越大,群落透光性越好,土壤升温越快,因此太阳辐射量越大,日均土壤呼吸速率越大[6,47]。

间接作用Indirecteffect作用值EstimateP放牧率通过土壤含水量对土壤呼吸的作用TheeffectofSRonRsbySM0.2716<0.00光合有效辐射通过群落盖度对土壤呼吸的作用TheeffectofPARonRsbyC1.18050.019

图4 祁连山北坡春秋季牧场土壤呼吸通径分析Fig. 4 The path analysis of soil respiration in spring-autumn pasture on north slope of Qilian Mountains

注: Rs,土壤呼吸; SR,放牧率; Ts,土壤温度; SM,土壤含水量; PAR, 光合有效辐射; C,群落盖度。

Note: Rs, soil respiration; SR, stoking rate; Ts, soil temperatute; SM, soil moisture; PAR, photosynthetically available radiation; C, community coverage.

4 结论

随放牧率增大,冬季牧场土壤呼吸速率减小,春秋季和夏季牧场土壤呼吸速率增大。土壤呼吸主要影响因子,冬季牧场为放牧率、土壤含水量与土壤温度,春秋季牧场为放牧率、光合有效辐射、土壤温度、土壤含水量和群落盖度,夏季牧场为坡位。冬季牧场的土壤含水量和土壤温度分别对其土壤呼吸起正向直接作用和负向直接作用,放牧率通过土壤表层温度对土壤呼吸起负向间接作用;春秋季牧场放牧率、土壤温度、土壤含水量、群落盖度主要对土壤呼吸起直接作用,光合有效辐射对土壤呼吸主要起间接作用;夏季牧场的土壤呼吸速率阴坡坡顶>坡谷>坡中,阳坡为坡中>坡顶>坡谷。冬季牧场Rs可分别由Rs=0.436-0.012Ts+0.018SM和Rs=0.707+0.002SR-0.02Ts估测;春秋季牧场Rs可由Rs=-0.239+0.003PAR-0.001C估测。

References:

[1] Chen J,Shi W,Cao J.Effects of grazing on ecosystem CO2exchange in a meadow grassland on the Tibetan Plateau during the growing season.Environmental Management,2015,55(2):347-359.

[2] Scharlemann J P W,Tanner E V J,Hiederer R.Global soil carbon:Understanding and managing the largest terrestrial carbon pool.Carbon Management,2014,5(1):81-91.

[3] Zhuoting W U,Dijkstra P,Koch G W,Penuelas J,Hugate B A.Responses of terrestrial ecosystems to temperature and precipitation change:A meta-analysis of experimental manipulation.Global Change Biology,2011,17(2):927-942.

[4] 侯扶江,杨中艺.放牧对草地的作用.生态学报,2006,26(1):244-264. Hou F J,Yang Z Y.Efects of grazing of livestock on grassland.Acta Ecologica Sinica,2006,26(1):244-264.(in Chinese)

[5] Hou X,Wang Z,Michael S P,Ji L,Yun X.The response of grassland productivity,soil carbon content and soil respiration rates to different grazing regimes in a desert steppe in northern China.Rangeland Journal,2014,36(6):573-582.

[6] 张秀敏,陈先江,侯扶江.陇东典型草原不同坡向土壤呼吸对模拟降雨的短期响应.草业科学,2014,31(10):1820-1824. Zhang X M,Chen X J,Hou F J.Temporary responses of soil respiration to precipitation in simulated typical steppe on the eastern Gansu Loess Plateau.Pratacultural Science,2014,31(10):1820-1824.(in Chinese)

[7] 揣小伟,黄贤金,郑泽庆,张梅,廖启林,赖力,卢俊宇.江苏省土地利用变化对陆地生态系统碳储量的影响.资源科学,2011,33(10):1932-1939. Chuai X W,Huang X J,Zheng Z Q,Zhang M,Liao Q L,Lai L,Lu J Y.Land use change and its influence on carbon storage of terrestrial ecosystems in Jiangsu Province.Resources Science,2011,33(10):1932-1939.(in Chinese)

[8] 侯扶江,安玉峰.近10年鹿放牧生态研究进展.草业学报,2000,9(2):24-31.

[9] 侯扶江,常生华,于应文,林慧龙.放牧家畜的践踏作用研究评述.生态学报,2004,24(4):784-789. Hou F J,Chang S H,Yu Y W,Lin H L.A review on trampling by grazed livestock.Acta Ecologica Sinica,2004,24(4):784-789.(in Chinese)

[10] 张新杰,韩国栋,王忠武.不同载畜率对短花针茅荒漠草原土壤呼吸的影响.生态环境学报,2014(5):743-748. Zhang X J,Han G D,Wang Z W.Effect of different stocking rate on soil respiration inStipabrevifloradesert steppe.Ecology & Environmental Sciences,2014(5):743-748.(in Chinese)

[11] Wang W,Zeng W J,Chen W L,Zeng H,Fang J Y.Soil Respiration and organic carbon dynamics with grassland conversions to woodlands in temperate China.PLoS One,2013,8(8):e71986.doi:10.1371/journal.pone.0071986

[12] 刘晓妮,李刚,赵祥,张宾宾,刘碧荣,董宽虎,王永新,任国华.放牧对赖草群落生物量及植物多样性的影响.草地学报,2014,22(5):942-948. Liu X N,Li G,Zhao X,Zhang B B,Liu B R,Dong K H,Wang Y X,Ren G H.Effects of grazing on the biodiversity and productivity ofLeymussecalinuscommunities.Acta Agrestia Sinica,2014,22(5):942-948.(in Chinese)

[13] 阿木日吉日嘎拉,红梅,韩国栋,高福光,赵巴音那木拉,刘超川.不同放牧强度对短花针茅荒漠草原土壤呼吸的影响.土壤通报,2013(2):321-327. Amurjirgala,Hong M,Han G D,Gao F G,Zhao Bayinnamula,Liu C C.Effects of different grazing intensity on soil respiration in theStipabrevifloradesert steppe.Chinese Journal of Soil Science,2013(2):321-327.(in Chinese)

[14] Cao G M,Tang Y H,Mo W H,Wang Y S,Li Y N,Zhao X Q.Grazing intensity alters soil respiration in an alpine meadow on the Tibetan plateau.Soil Biology & Biochemistry,2004,36(2):237-243.

[15] 贺桂香,李凯辉,宋韦,公延明,刘学军,胡玉昆,田长彦.新疆天山高寒草原不同放牧管理下的CO2,CH4和N2O通量特征.生态学报,2014,34(3):674-681. He G X,Li K H,Song W,Gong Y M,Liu X J,Hu Y K,Tian C Y.The fluxes of carbon dioxide,methane and nitrous oxide in alpine grassland of the Tianshan Mountains,Xinjiang.Acta Ecologica Sinica,2014,34(3):674-681.(in Chinese)

[16] 邓钰,柳小妮,闫瑞瑞,王旭,杨桂霞,任正超,辛晓平.呼伦贝尔草甸草原土壤呼吸及其影响因子对不同放牧强度的响应.草业学报,2013,22(2):22-29. Deng Y,Liu X N,Yan R R,Wang X,Yang G X,Ren Z C,Xin X P.Soil respiration of Hulunber meadow steppe and response of its controlling factors to different grazing intensities.Acta Agrestia Sinica,2013,22(2):22-29.(in Chinese)

[17] 陈吉,王京,高志娟,郭亚力,吴爱娇,徐炳成.黄土丘陵区白羊草与达乌里胡枝子混播草地土壤呼吸日变化特征.草业科学,2015,32(1):19-27. Chen J,Wang J,Gao Z J,Guo Y L,Wu A J,Xu B C.Diurnal variations of soil respiration inBothriochloaischaemumandLespedezadavuricamixture pasture at Loess Hilly Region.Pratacultural Science,2015,32(1):19-27.(in Chinese)

[18] 郭小伟,杜岩功,林丽,李以康,张法伟,李茜,刘淑丽,欧阳经政,曹广民.青藏高原北缘3种高寒草地的CH4、CO2和N2O通量特征的初步研究.草业科学,2016,33(1):27-37. Guo X W,Du Y G,Li L,Li Y K,Zhang F W,Li Q,Liu S L,Ouyang J Z,Cao G M.CH4,CO2and N2O flux among three types of alpine meadow in the north regions of Qinghai-Tibetan Plateau.Pratacultural Science,2016,33(1):27-37.(in Chinese)

[19] Bölter M,Wang Y,Chang Q R,Duttmann R,Marx K,Petersen J F,Wang Z L.Functional dependencies of soil CO2emissions on soil biological properties in northern German agricultural soils derived from a glacial till.Acta Agriculturae Scandinavica,Section B-Soil & Plant Science,2015,65(3):233-245.

[20] 谢国雄,沈建国,王京文,张奇春,侯昌萍,梁颖颖.不同经营措施下毛竹林土壤有机碳组分研究.中国农学通报,2013,29(31):53-57. Xie G X,Shen J G,Wang J W,Zhang Q C,Hou C P,Liang Y Y.Research on soil organic carbon components under different management in bamboo forest.Chinese Agricultural Science Bulletin,2013,29(31):53-57.(in Chinese)

[21] 郭明英,卫智军,运向军,吴艳玲,刘红梅,李耀,辛晓平.放牧对草原土壤呼吸的影响.草业科学,2011,28(5):729-736. Guo M Y,Wei Z J,Yun X J,Wu Y L,Liu H M,Li Y,Xin X P.Effect of grazing on grassland soil respiration.Pratacultural Science,2011,28(5):729-736.(in Chinese)

[22] 王旭,闫瑞瑞,邓钰,闫玉春,辛晓平.放牧对呼伦贝尔草甸草原土壤呼吸温度敏感性的影响.环境科学,2014,35(5):1909-1914. Wang X,Yan R R,Deng Y,Yan Y C,Xin X P.Effect of grazing on the temperature sensitivity of soil respiration in Hulumber meadow steppe.Environmental Science,2014,35(5):1909-1914.(in Chinese)

[23] 阳小成,阿舍小虎,苗原,刘银占.川西北高寒草甸不同放牧模式对土壤呼吸的影响.生态学报,2016,36(17):5371-5378. Yang X C,Ashe X H,Miao Y,Liu Y Z.Response of soil respiration rate to grazing patterns in an alpine meadow,Northwestern Sichuan,China.Acta Ecologica Sinica,2016,36(17):5371-5378.(in Chinese)

[24] 梁茂伟,白雪,王英舜,苗白岭,包桂荣,王譞,梁存柱.适度放牧对内蒙古典型草原碳循环的影响.内蒙古大学学报:自然科学版,2016(3):278-284. Liang M W,Bai X,Wang Y S,Miao B L,Bao G R,Wang X,Liang C Z.The effect of moderate grazing on carbon cycle of the typical steppe in Inner Mongolia.Journal of Inner Mongolia University:Natural Science Edition,2016(3):278-284.(in Chinese)

[25] Wei D,Ri X,Wang Y H,Wang Y S,Liu Y W,Yao T D.Responses of CO2,CH4and N2O fluxes to livestock exclosure in an alpine steppe on the Tibetan Plateau,China.Plant and Soil,2012,359(1-2):45-55.

[26] Liebig M A,Kronberg S L.Carbon dioxide efflux from long-term grazing management systems in a semiarid region.Agriculture,Ecosystems & Environment,2013,164(1):137-144.

[27] Thomas A D.Impact of grazing intensity on seasonal variations in soil organic carbon and soil CO2efflux in two semiarid grasslands in southern Botswana.Philosophical Transactions of the Royal Society B Biological Sciences,2011,367:3076-3086.

[29] Lin X W,Zhang Z H,Wang S P,Xie Z B.Response of ecosystem respiration to warming and grazing during the growing seasons in the alpine meadow on the Tibetan plateau.Agricultural and Forest Meteorology,2011,151(7):792-802.

[30] 余磊朝,郭雪莲,王山峰,刘双圆,王雪.牦牛放牧对青藏高原东南缘泥炭沼泽湿地CO2排放的影响.草业科学,2016,33(12):2418-2424. Yu L C,Guo X F,Wang S F,Liu S Y,Wang X.Effects of yak grazing on CO2fluxes in peat bogs in the northwest Yunnan Plateau.Pratacultural Science,2016,33(12):2418-2424.(in Chinese)

[31] 田林卫,周华坤,刘泽华,魏晴,姚步青,王文颖,赵新全.高寒草甸区不同生境土壤呼吸变化规律及其与水热因子的关系.草业科学,2014,31(7):1233-1240. Tian L W,Zhou H K,Liu Z H,Wei Q,Yao B Q,Wang W Q,Zhao X Q.Soil respiration variation and its relationship with hydrothermic factor under different biotopes of alpine meadow distributed area.Pratacultural Science,2014,31(7):1233-1240.(in Chinese)

[32] 任继周,胡自治,牟新待,张普金.草原的草原综合顺序分类法及其草原发生学意义.中国草地,1980,18(1):12-24.

[33] 侯扶江,南志标,肖金玉,常生华.重牧退化草地的植被、土壤及其耦合特征.应用生态学报,2002,13(8):915-922. Hou F J,Nan Z B,Xiao J Y,Chang S H.Characteristics of vegetation,soil,and their coupling of degraded grasslands.Chinese Journal of Applied Ecology,2002,13(8):915-922.(in Chinese)

[34] Zhang Y,Chen X J,Cheng Y X,Chang S H,Hou F J.Effects of stocking rates on functional group diversity and forage quality in rangeland of Qilian Mountain,China.Journal of Environmental Biology,2015,36(4):713-719.

[35] 侯扶江.对肃南县甘肃马鹿养殖的几点建议.草业与西部大开发学术研讨会暨中国草原学会2000年学术年会.兰州:中国草原学会,2000:192.

[36] 王化,侯扶江,袁航,万秀丽,徐磊,陈先江,常生华.高山草原放牧率与群落物种丰富度.草业科学,2013,30(3):328-333. Wang H,Hou F J,Yuan H,Wan X L,Xu L,Chen X J,Chang S H.Relationships between stocking rate and species richness on alpine steppe.Pratacultural Science,2013,30(3):328-333.(in Chinese)

[37] Yuan H,Hou F.Grazing intensity and soil depth effects on soil properties in alpine meadow pastures of Qilian Mountain in northwest China.Acta Agriculturae Scandinavica,Section B-Soil & Plant Science,2015,65(3):222-232.

[38] 侯扶江,任继周.甘肃马鹿冬季放牧践踏作用及其对土壤理化性质影响的评价.生态学报,2003,23(3):486-495. Hou F J,Ren J Z.Evaluation on trampling of grazed Gansu wapiti (CervuselaphuskansuensisPo cock) and its effects on soil property in winter grazing land.Acta Ecologica Sinica,2003,23(3):486-495.(in Chinese)

[39] Chen J B,Hou F J,Chen X J,Wan X Z,Millner J.Stocking rate and grazing season modify soil respiration on the Loess Plateau,China.Rangeland Ecology & Management,2015,68(1):48-53.

[40] Chen J,Zhou X H,Wang J F,Hruska T,Shi W Y,Cao J J,Zhang B C,Xu G X,Chen Y Z,Luo Y Q.Grazing exclusion reduced soil respiration but increased its temperature sensitivity in a meadow grassland on the Tibetan Plateau.Ecology & Evolution,2016,6(3):675-687.

[41] Berryman E M,Barnard H R,Adams H R,Burns M A,Gallo E,Brooks P D.Complex terrain alters temperature and moisture limitations of forest soil respiration across a semiarid to subalpine gradient.Journal of Geophysical Research:Biogeosciences,2015,120(4):707-723.

[42] 赵蓉,李小军,赵洋,杨昊天,陈栋.固沙植被区两类结皮斑块土壤呼吸对不同频率干湿交替的响应.生态学杂志,2015,34(1):138-144. Zhao R,Li X J,Zhao Y,Yang H T,Chen D.CO2efflux from two biologically-crusted soils in response to drying-rewetting cycles with different frequencies in the Tengger Desert.Chinese Journal of Ecology,2015,34(1):138-144.(in Chinese)

[43] Li Y F,Li Z H,Li Z H,Geng X L,Deng X Z.Numerical simulation of the effects of grassland degradation on the surface climate in overgrazing area of north west China.Advances in Meteorology,2013,2013(4):183-186.

[44] Prem E M,Reitschuler C,Illmer P.Livestock grazing on alpine soils causes changes in abiotic and biotic soil properties and thus in abundance and activity of microorganisms engaged in the methane cycle.European Journal of Soil Biology,2014,62:22-29.

[45] Keidel L,Kammann C,Grünhage L,Moser G,Muller C.Positive feedback of elevated CO2on soil respiration in late autumn and winter.Biogeosciences,2015,12(4):1257-1269.

[46] 徐海红,侯向阳,那日苏.不同放牧制度下短花针茅荒漠草原土壤呼吸动态研究.草业学报,2011,20(2):219-226. Xu H Y,Hou X Y,Narisu.Dynamics of soil respiration under different grazing systems in aStipabrevifloradesert steppe.Acta Prataculturae Sinica,2011,20(2):219-226.(in Chinese)

[47] 吴启华,李英年,刘晓琴,李红琴,毛绍娟.牧压梯度下青藏高原高寒杂草类草甸生态系统呼吸和碳汇强度估算.中国农业气象,2013,34(4):390-395. Wu Q H,Li Y N,Liu X Q,Li H Q,Mao S J.Ecosystem respiration and carbon sink strength of the alpine weeds meadow in Qinghai-Tibetan Plateau under grazing gradient.Chinese Journal of Agrometeorology,2013,34(4):390-395.(in Chinese)

(责任编辑 武艳培)

Soil respiration in three types of seasonal pastures in summer on the northern slope of Qilian Mountains

Guo Ya-rong1,2, Hou Fu-jiang1,2, Yu Ying-Wen1,2

(1.State Key Laboratory of Grassland Agro-escosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China; 2.Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture, Lanzhou University, Lanzhou 730020, China)

To facilitate the management of carbon sink, soil respiration and factors affecting it were measured and analysed in summer pasture, winter pasture, and spring-autumn pasture on the northern slope of Qilian Mountains in summer. Daily soil respiration (Rs) was 0.24, 0.19, and 0.26 μmol·(m2·s)-1in the winter pasture, spring-autumn pasture, and summer pasture, respectively. With increase in stocking rate, Rsdecreased in winter pasture, whereas that in the spring-autumn pasture and summer pasture revealed the opposite trend. In winter pasture, Rswas significantly positively correlated with soil moisture (SM) and significantly negatively correlated with stocking rate (SR) and soil temperature (Ts) (P<0.05). However, in spring-autumn pasture, Rswas significantly positively correlated with SR, photosynthetically available radiation (PAR), and SM (P<0.05), but significantly negatively correlated with soil temperature (Ts) and community coverage (C) (P<0.05). A structural model revealed that the indirect negative effect of SR by Tson Rswas higher than the direct positive effect of SM in winter pasture. The direct negative effect of C on Rswas higher than the direct positive effect of SR in spring-autumn pasture. In winter pasture, Rscan be estimated better by Tsand SM,Rs=0.436-0.012ST+0.018SM(R2=0.775,P=0.037). In spring-autumn pasture, Rscan be estimated better by PAR and C,Rs=-0.239+0.003PAR-0.001C(R2=0.979,P=0.004).

grazing; alpine grassland; alpine shrub meadow; soil repiration; soil temperature; soil moisture; photosynthetically available radiation

Hou Fu-jiang E-mail:cyhoufj@lzu.edu.cn

10.11829/j.issn.1001-0629.2016-0454

2016-08-31 接受日期:2017-05-04

教育部“创新团队发展计划”(IRT_17R50);国家科技支撑计划项目(2012BAD13B05)

郭雅蓉(1993-),女,山西长治人,在读硕士生,研究方向为作物-家畜综合系统。E-mail:guoyr15@lzu.edu.cn

侯扶江(1971-),男,河南扶沟人,教授,博士,研究方向为草地-家畜生产系统。E-mail:cyhoufj@lzu.edu.cn

S152

A

1001-0629(2017)08-1561-10

郭雅蓉,侯扶江,于应文.祁连山北坡3个季节性牧场夏季的土壤呼吸.草业科学,2017,34(8):1561-1570.

Guo Y R,Hou F J,Yu Y W.Soil respiration in three types of seasonal pastures in summer on the northern slope of Qilian Mountains.Pratacultural Science,2017,34(8):1561-1570.

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