亚热带常绿阔叶林土壤微生物量动态变化及其对氮磷添加的响应
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摘要
土壤微生物是土壤生物化学过程的驱动者,对环境变化极其敏感。为了探讨不同年份气候差异及不同坡位土壤微生物对氮沉降的响应机制,在安徽南部查湾自然保护区选择不同坡位亚热带常绿阔叶林,就氮、磷添加对土壤微生物量碳(MBC)、氮(MBN)的影响进行了为期3年的试验研究。选择中坡和坡顶两种立地类型,分别设置3种控制实验,对照(CK,0 kg N?hm~(-2)?a~(-1))、氮添加(N,100 kg N?hm~(-2)?a~(-1))、氮磷添加(N+P,100 kg N?hm~(-2)?a~(-1)+50 kg P?hm~(-2)?a~(-1))。取样后,测试不同处理土壤MBC、MBN及土壤理化性质。结果表明,氮磷添加后,不同坡位MBC和MBN季节变化存在差异。与対照相比,氮磷和氮添加中坡MBC分别降低了14.6%和15.4%,而在坡顶,两种处理MBC分别提高5.8%和2.1%。中坡MBC变化范围为171.94~2 151.35 mg?kg~(-1),MBN变化范围为52.14~203.3 mg?kg~(-1);坡顶MBC变化范围为102.49~2 219.95 mg?kg~(-1),MBN变化范围为38.56~203.3 mg?kg~(-1)。中坡第2年、第3年及坡顶第3年氮磷和氮添加降低了ω(MBC)/ω(MBN)比,不同坡位ω(MBC)/ω(MBN)比均值为7.88~14.21。土壤微生物量的季节变化显著,土壤MBN在生长季节(5月、7月、9月及11月)较高,最低值出现在休眠期(1月);养分添加改变了土壤MBN季节变化规律。季节、坡位改变了土壤微生物量碳氮和土壤养分的相关性。因此,养分添加对不同立地土壤微生物的影响不同,且不同年份存在差异。长期氮、磷添加降低了ω(MBC)/ω(MBN)比值,但不同坡位反应时间存在差异。土壤MBC、MBN不同年份之间差异显著,主要受不同年份降雨和气温变化控制。冗余分析(RDA)表明,月降水频率、不同年份气温及降水差异、林分因子及土壤理化性质均对土壤微生物量存在显著影响,其季节变化由降水频率(月降水天数)、降水量及气温变化和月降水量及气温波动差异(月标准差)所控制。
Soil microbes are the drivers of soil biochemical processes and are extremely sensitive to environmental changes. In order to explore the climate differences in different years and the response mechanisms of soil microorganisms to nitrogen deposition at different slope positions, the subtropical evergreen broad-leaved forests with different slope positions were selected in the Zhawan Nature Reserve in southern Anhui Province, and nitrogen and phosphorus were added to study the effect of the soil microbial biomass carbon(MBC) and nitrogen(MBN) over a three-year period. Two kinds of site types were selected: middle slope and top slope, and three control experiments were set up, control(CK, N 0 kg?hm~(-2)?a~(-1)), nitrogen addition(N, N 100 kg?hm~(-2)?a~(-1)), and nitrogen and phosphorus addition(N+P, N 100 kg?hm~(-2)?a~(-1)+P 50 kg?hm~(-2)?a~(-1)). After sampling, soil MBC, MBN, and soil physical and chemical properties were tested. The results showed that there were differences in soil microbial biomass carbon(MBC) and nitrogen(MBN) between the two slope positions after N+P and N additions. Compared with the control, the MBC on the mid-slope decreased by 14.6% and 15.4% after N+P and N additions, respectively. On the flat ridge, the MBC was increased by 5.8% and 2.1% after N+P and N additions, respectively. The range of MBC varied from 171.94 to 2 151.35 mg?kg~(-1), and MBN from 52.14 to 203.3 mg?kg~(-1) on the mid-slope. On the flat ridge, the mean MBC ranged from 102.49 to 2 219.95 mg?kg~(-1) and MBN from 38.56 to 203.3 mg?kg~(-1). After N+P and N additions, the mean MBC/MBN ratios were decreased in the 2 nd and 3 rd years on mid-slope and in the 3 rd year on the flat ridge. The mean MBC/MBN ratios ranged from 7.88 to 14.21 for the different slope positions. There existed significant seasonal variation in soil microbial biomass, with relatively high MBN in the growing season(May, July and November) and lowest in the dormant season(January). The N+P and N additions changed the seasonal variation of MBN, while not change of MBC. The relationship between soil microbial biomass and soil nutrient was changed by the interaction between seasonal variation and site conditions. Consequently, the N+P and N additions had different effects on soil microbial biomass at different sites, and there was different among years. The long-term additions of N+P or N could result in decrease of MBC/MBN ratio. However, there was different in response time between the two slope positions. The seasonal variation of soil microbial biomass was not uniform among years, which was mainly controlled by annual precipitation and temperature. Redundancy analysis(RDA) indicated that monthly rainfall frequency, annual temperature and precipitation changes, stand factor and soil physicochemical properties had significant effects on soil microbial biomass. The seasonal variation of soil microbial biomass was controlled by monthly rainfall days, precipitation and temperature changes and monthly rainfall and temperature fluctuations(monthly standard deviation).
Soil microbes are the drivers of soil biochemical processes and are extremely sensitive to environmental changes. In order to explore the climate differences in different years and the response mechanisms of soil microorganisms to nitrogen deposition at different slope positions, the subtropical evergreen broad-leaved forests with different slope positions were selected in the Zhawan Nature Reserve in southern Anhui Province, and nitrogen and phosphorus were added to study the effect of the soil microbial biomass carbon(MBC) and nitrogen(MBN) over a three-year period. Two kinds of site types were selected: middle slope and top slope, and three control experiments were set up, control(CK, N 0 kg?hm~(-2)?a~(-1)), nitrogen addition(N, N 100 kg?hm~(-2)?a~(-1)), and nitrogen and phosphorus addition(N+P, N 100 kg?hm~(-2)?a~(-1)+P 50 kg?hm~(-2)?a~(-1)). After sampling, soil MBC, MBN, and soil physical and chemical properties were tested. The results showed that there were differences in soil microbial biomass carbon(MBC) and nitrogen(MBN) between the two slope positions after N+P and N additions. Compared with the control, the MBC on the mid-slope decreased by 14.6% and 15.4% after N+P and N additions, respectively. On the flat ridge, the MBC was increased by 5.8% and 2.1% after N+P and N additions, respectively. The range of MBC varied from 171.94 to 2 151.35 mg?kg~(-1), and MBN from 52.14 to 203.3 mg?kg~(-1) on the mid-slope. On the flat ridge, the mean MBC ranged from 102.49 to 2 219.95 mg?kg~(-1) and MBN from 38.56 to 203.3 mg?kg~(-1). After N+P and N additions, the mean MBC/MBN ratios were decreased in the 2 nd and 3 rd years on mid-slope and in the 3 rd year on the flat ridge. The mean MBC/MBN ratios ranged from 7.88 to 14.21 for the different slope positions. There existed significant seasonal variation in soil microbial biomass, with relatively high MBN in the growing season(May, July and November) and lowest in the dormant season(January). The N+P and N additions changed the seasonal variation of MBN, while not change of MBC. The relationship between soil microbial biomass and soil nutrient was changed by the interaction between seasonal variation and site conditions. Consequently, the N+P and N additions had different effects on soil microbial biomass at different sites, and there was different among years. The long-term additions of N+P or N could result in decrease of MBC/MBN ratio. However, there was different in response time between the two slope positions. The seasonal variation of soil microbial biomass was not uniform among years, which was mainly controlled by annual precipitation and temperature. Redundancy analysis(RDA) indicated that monthly rainfall frequency, annual temperature and precipitation changes, stand factor and soil physicochemical properties had significant effects on soil microbial biomass. The seasonal variation of soil microbial biomass was controlled by monthly rainfall days, precipitation and temperature changes and monthly rainfall and temperature fluctuations(monthly standard deviation).
引文
ARNEBRANDT K,BAATH E,SODERSTROM B.1990.Changes in fungal community structure after fertilization of Scots pine forest soils with ammonium nitrate or urea[J].Soil Biology and Biochemistry,22(3):309-312.
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CHEN C R,XU Z H,BLUMFIELD T J,et al.2003.Soil microbial biomass during the early establishment of hoop pine plantation:seasonal variation and impacts of site preparation[J].Forest Ecology and Management,186(1-3):213-225.
CUSACK D F,SILVER W L,TORN M S,et al.2011.Changes in microbial community characteristics and soil organic matter with nitrogen additions in two tropical forests[J].Ecology,92(3):621-632.
DEVI N B,YADAVA P S.2006.Seasonal dynamics in soil microbial biomass C,N and P in a mixed-oak forest ecosystem of Manipur,Northeast India[J].Applied Soil Ecology,31(3):220-222.
FENG W T,ZOU X M,SCHAEFER D.2009.Above-and belowground carbon inputs affect seasonal variations of soil microbial biomass in a subtropical monsoon forest of southwest China[J].Soil Biology and Biochemistry,41(5):978-983.
PAUL E A,CLARK F E.1996.Soil Microbiology and Biochemistry[M].San Diego:Academic Press.
PENUEL A S J,SARDANS J,RIVAS-UBACH,et al.2012.The human-induced imbalance between C,N and P in Earth'life system[J].Global Change Biology,18(1):3-6.
REDDING M R,SHORTEN P R,LEWIS R,et al.2016.Soil N availability,rather than N deposition,controls indirect N2O emission[J].Soil Biology and Biochemistry,95:288-298.
ROELOFS J G M,KEMPERS A J,et al.1985.The effect of air-borne ammonium sulphate on Pinus nigra var.maritima in the Netherlands[J].Plant Soil,84(1):45-56.
SUGIHARA S,FUNAKAWA S,KILASARA M,et al.2010.Effect of land management and soil texture on seasonal variations in soil microbial biomass in dry tropical agroecosystems in Tanzania[J].Applied Soil Ecology,44(1):80-88.
VANDER EERDEN L J,LEKKERKERK L J A,SMEULDERS S M.1982.Effects of atmospheric ammonia and ammonium sulphate in forest canopy throughfall[J].Nature,299(5883):548-550.
WALLENSTEIN M D,MCNULTY S,FERNANDEZ I J,et al.2006.Nitrogen fertilization decreases forest soil fungal and bacterial biomass in three long-term experiments[J].Forest Ecology and Management,222(1-3):459-468.
WANG X F,LI S Y,BAI K J,et al.1998.Influence of doubled CO2 on plant growth and soil microbial biomass C and N[J].Acta Botanica Sinica,40(12):1169-1172.
WANG X,XU L G,WAN R R,et al.2016.Seasonal variations of soil microbial biomass within two typical wetland areas along the vegetation gradient of Poyang Lake,China[J].Catena,137:483-493.
WARREN M,ZOU X M.2003.Seasonal nitrogen retention in temperate hardwood forests:The“vernal dam”hypothesis and case studies[J].Acta Phytoecologica Sinica,27(1):11-15.
ZAK D R,GROFFMAN P M,PREGITZER K S,et al.1990.The“Vernal Dam”:plant-microbe competition for nitrogen in northern hardwood forests[J].Ecology,71(2):651-656.
ZHOU G Y,WEI X H,WU Y P,et al.2011.Quantifying the hydrological responses to climate change in an intact forested small watershed in Southern China[J].Global Change Biology,17(12):3736-3746.
成毅,安韶山,马云飞.2010.宁南山区不同坡位土壤微生物生物量和酶活性的分布特征[J].水土保持研究,17(5):148-153.
戴允泽,傅欣蕾,张莎莎,等.2017.安徽查湾自然保护区常绿阔叶林不同林分土壤微生物群落代谢特征[J].生态环境学报,26(7):1114-1121.
李延茂,胡江春,汪思龙,等.2004.森林生态系统中土壤微生物的作用与应用[J].应用生态学报,15(10):1943-1946.
孟盈,薛敬意,沙丽清,等.2001.西双版纳不同热带森林下土壤铵态氮和硝态氮动态研究植物[J].生态学报,25(1):99-104.
莫江明,彭少鳞,方运霆,等.2001.鼎湖山马尾松针叶阔叶混交林土壤有效氮动态的初步研究[J].生态学报,21(3):492-497.
涂玉,尤业明,孙建新.2012.油松-辽东栋混交林地表凋落物与氮添加对土壤微生物量碳、氮及其活性的影响[J].应用生态学报,23(9):2325-2331.
王晖,莫江明,薛璟花,等.2006.氮沉降增加对森林凋落物分解酶活性的影响[J].热带亚热带植物学报,14(6):539-546.
王志勇.2012.模拟氮沉降对亚热带人工林土壤微生物的影响[J].长沙:中南林业科技大学学位论文.
张地,张育新,曲来叶,等.2012.坡位对东灵山辽东栋林土壤微生物量的影响[J].生态学报,32(20):6412-6421.
赵超,彭赛,阮宏华,等.2015.氮沉降对土壤微生物影响的研究进展[J].南京林业大学学报(自然科学版),39(3):149-155.
周嘉聪,刘小飞,郑永.2017.氮沉降对中亚热带米槠天然林微生物生物量及酶活性的影响[J].生态学报,37(1):127-135.
周世兴,皱平,肖永祥.2017.模拟氮沉降对华西雨屏区天然常绿阔叶林土壤微生物碳和氮的影响[J].应用生态学报,28(1):12-18.
CAO Z P,LI D P,HAN X M.2011.The fungal to bacterial ratio in soil food webs,and its measurement[J].Acta Ecologica Sinica,31(16):4741-4748.
CHEN C R,XU Z H,BLUMFIELD T J,et al.2003.Soil microbial biomass during the early establishment of hoop pine plantation:seasonal variation and impacts of site preparation[J].Forest Ecology and Management,186(1-3):213-225.
CUSACK D F,SILVER W L,TORN M S,et al.2011.Changes in microbial community characteristics and soil organic matter with nitrogen additions in two tropical forests[J].Ecology,92(3):621-632.
DEVI N B,YADAVA P S.2006.Seasonal dynamics in soil microbial biomass C,N and P in a mixed-oak forest ecosystem of Manipur,Northeast India[J].Applied Soil Ecology,31(3):220-222.
FENG W T,ZOU X M,SCHAEFER D.2009.Above-and belowground carbon inputs affect seasonal variations of soil microbial biomass in a subtropical monsoon forest of southwest China[J].Soil Biology and Biochemistry,41(5):978-983.
PAUL E A,CLARK F E.1996.Soil Microbiology and Biochemistry[M].San Diego:Academic Press.
PENUEL A S J,SARDANS J,RIVAS-UBACH,et al.2012.The human-induced imbalance between C,N and P in Earth'life system[J].Global Change Biology,18(1):3-6.
REDDING M R,SHORTEN P R,LEWIS R,et al.2016.Soil N availability,rather than N deposition,controls indirect N2O emission[J].Soil Biology and Biochemistry,95:288-298.
ROELOFS J G M,KEMPERS A J,et al.1985.The effect of air-borne ammonium sulphate on Pinus nigra var.maritima in the Netherlands[J].Plant Soil,84(1):45-56.
SUGIHARA S,FUNAKAWA S,KILASARA M,et al.2010.Effect of land management and soil texture on seasonal variations in soil microbial biomass in dry tropical agroecosystems in Tanzania[J].Applied Soil Ecology,44(1):80-88.
VANDER EERDEN L J,LEKKERKERK L J A,SMEULDERS S M.1982.Effects of atmospheric ammonia and ammonium sulphate in forest canopy throughfall[J].Nature,299(5883):548-550.
WALLENSTEIN M D,MCNULTY S,FERNANDEZ I J,et al.2006.Nitrogen fertilization decreases forest soil fungal and bacterial biomass in three long-term experiments[J].Forest Ecology and Management,222(1-3):459-468.
WANG X F,LI S Y,BAI K J,et al.1998.Influence of doubled CO2 on plant growth and soil microbial biomass C and N[J].Acta Botanica Sinica,40(12):1169-1172.
WANG X,XU L G,WAN R R,et al.2016.Seasonal variations of soil microbial biomass within two typical wetland areas along the vegetation gradient of Poyang Lake,China[J].Catena,137:483-493.
WARREN M,ZOU X M.2003.Seasonal nitrogen retention in temperate hardwood forests:The“vernal dam”hypothesis and case studies[J].Acta Phytoecologica Sinica,27(1):11-15.
ZAK D R,GROFFMAN P M,PREGITZER K S,et al.1990.The“Vernal Dam”:plant-microbe competition for nitrogen in northern hardwood forests[J].Ecology,71(2):651-656.
ZHOU G Y,WEI X H,WU Y P,et al.2011.Quantifying the hydrological responses to climate change in an intact forested small watershed in Southern China[J].Global Change Biology,17(12):3736-3746.
成毅,安韶山,马云飞.2010.宁南山区不同坡位土壤微生物生物量和酶活性的分布特征[J].水土保持研究,17(5):148-153.
戴允泽,傅欣蕾,张莎莎,等.2017.安徽查湾自然保护区常绿阔叶林不同林分土壤微生物群落代谢特征[J].生态环境学报,26(7):1114-1121.
李延茂,胡江春,汪思龙,等.2004.森林生态系统中土壤微生物的作用与应用[J].应用生态学报,15(10):1943-1946.
孟盈,薛敬意,沙丽清,等.2001.西双版纳不同热带森林下土壤铵态氮和硝态氮动态研究植物[J].生态学报,25(1):99-104.
莫江明,彭少鳞,方运霆,等.2001.鼎湖山马尾松针叶阔叶混交林土壤有效氮动态的初步研究[J].生态学报,21(3):492-497.
涂玉,尤业明,孙建新.2012.油松-辽东栋混交林地表凋落物与氮添加对土壤微生物量碳、氮及其活性的影响[J].应用生态学报,23(9):2325-2331.
王晖,莫江明,薛璟花,等.2006.氮沉降增加对森林凋落物分解酶活性的影响[J].热带亚热带植物学报,14(6):539-546.
王志勇.2012.模拟氮沉降对亚热带人工林土壤微生物的影响[J].长沙:中南林业科技大学学位论文.
张地,张育新,曲来叶,等.2012.坡位对东灵山辽东栋林土壤微生物量的影响[J].生态学报,32(20):6412-6421.
赵超,彭赛,阮宏华,等.2015.氮沉降对土壤微生物影响的研究进展[J].南京林业大学学报(自然科学版),39(3):149-155.
周嘉聪,刘小飞,郑永.2017.氮沉降对中亚热带米槠天然林微生物生物量及酶活性的影响[J].生态学报,37(1):127-135.
周世兴,皱平,肖永祥.2017.模拟氮沉降对华西雨屏区天然常绿阔叶林土壤微生物碳和氮的影响[J].应用生态学报,28(1):12-18.