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浙江大学学报（农业与生命科学版）
浙江大学学报(农业与生命科学版)  2013, Vol. 39 Issue (3): 299-308    DOI: 10.3785/j.issn.1008-9209.2012.07.262
农业科学     
酒竹人工林土壤呼吸对氮输入的响应及其因子分析
李伟成1,2*,　王曙光1,2，　盛海燕3，　郑友苗1，  王树东1，　钟哲科1
（1.国家林业局竹子研究开发中心，杭州310012； 2.西南林业大学生命科学学院，昆明650224；
3.杭州市环境保护科学研究院，杭州310014）
Effects of nitrogen levels on  soil respiration of sympodial bamboo plantation and factor analysis
LI Weicheng1,2*, WANG Shuguang1,2, SHENG Haiyan3, ZHENG Youmiao1,  WANG Shudong1, ZHONG Zheke1
(1. National Bamboo Research Center, State Forestry Administration, Hangzhou 310012, China; 2. College of Life Sciences, Southwest Forestry University, Kunming 650224, China; 3. Hangzhou Academy of Environmental Science, Hangzhou 310014, China
)
 
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摘要： 以西南地区引种栽培的酒竹为对象，开展造林初期不同氮输入措施的试验以评价其对土壤呼吸的影响，并通过10 cm深处土壤温度（soil temperature at
   10 cm depth，T10）、土壤水溶性有机碳含量（soil water-soluble organic carbon content，WSOC ）和土壤含水量（soil water content，SW）探讨其响应机制。结果显示：在不同氮输入处理下酒竹人工林T10、WSOC和SW的变化规律基本与土壤呼吸相似，全年呈现上升—高峰—下降—低谷的过程，雨季和旱季的差异性显著；土壤呼吸速率与T10呈极显著相关的指数关系，而与WSOC、SW呈极显著相关的线性关系；全年温度敏感指数Q10值在2.45~2.78之间，雨季的温度敏感性略低(Q10值在1.66~1.89之间)，旱季则较为特殊，对温度敏感，Q10值在4.85~9.54之间，N80和N160处理降低了土壤呼吸的温度敏感性；测得的WSOC数据波动较大，酒竹人工林的氮输入并不能提高T10和SW，但N80和N160相对提高了WSOC。SW和T10解释了全年在N0、N40、N80和N160处理下土壤呼吸变化的96.10%、94.30%、94.48%和92.99%，贡献了绝大部分信息量；雨季与旱季土壤呼吸的主导因素有所不同，雨季为SW，旱季为T10。
Abstract: Soil respiration is the primary way by which CO2 absorbed by terrestrial plants returns to the atmosphere. And it may have distinctly dynamic patterns at  different temporal scales since it is affected by diverse abiotic and biotic factors. Increasing deposition of nitrogen from the traditional cultivation of sympodial bamboos may lead to the sequestration of carbon in vegetation and soil. And the rising temperature and water content may increase the flux of CO2 from the soil, but the response of the ecosystem to simultaneous changes in all of these factors is still unknown. Meanwhile, to provide abundant supply of bamboo timber, afforestation of bamboo species such as Oxytenanthera braunii Pilger ap. Engler, Dendrocalamus brandisii Kurz and D. giganteus Munro is encouraged by the government but without scientific directions.  And chemical fertilizers are usually applied into fields unscientifically and blindly in the villages of southwest China. Subsequently, what will happen to the soil structure and how to balance soil nutrient environment in the situation of chemical fertilizer abuse?
In the context of climate change, the amount of nitrogen allocated to the soil is predicted to increase with the productivity of terrestrial ecosystem, and may alter soil carbon storage capacities. To provide the proof of soil respiration responding to the nitrogen input for sympodial bamboo afforestation at  the beginning period, we set up four  nitrogen fertilization (CO(NH2)2) levels in mid-high mountain of southeast China, i.e. N content of 0, 40, 80, 160 kg/hm2
  (expressed on  N0,
 N40, N80, N160, respectively), using the two-year old stump of wine bamboo which were planted every five  meters. The soil respiration rate is measured by using trenching method and infrared gas analyzer. The responding mechanism is discussed through analyzing the change of soil temperature at  10 cm   depth (T10), as well as changes of soil water-soluble organic carbon content (WSOC) and soil water content (SW).
Results showed that soil respiration rate was quite different between rainy and dry seasons. The soil respiration rate increased at the end of April or in the beginning of May when the rainy season arrived. Its wave crest arrived in July, Aug. and Sept., and then the rate decreased along with the dry season  in  Nov.,  Dec.,  Feb. and Mar., then the trough of soil respiration rate appeared. The variation rule of T10, WSOC and SW was  similar as this way. Exponential function could  be used to describe the relationship between T10  and respiration rate. Meanwhile, WSOC and SW showed a linear relationship with the respiration rate respectively, and  the regression test
indicted  that it was significant. And the temperature sensitivity value Q10 of a whole year was 2.45-2.78 nearby. In rainy season, Q10 decreased to 1.66-1.89, which indicated that the sensitivity of respiration rate responding to temperature decreased. On the contrary, Q10 ascended to 4.85-9.54 in dry season. The yearly data of WSOC were unstable, and the nitrogen input could not enhance T10 and SW, but N80 and N160 could increase WSOC relatively. The changes of SW and T10  explained 96.10%, 94.30%, 94.48% and 92.99% of the variation of soil respiration rate in the treatment of N0, N40, N80 and N160, which contributed most of the information. The main factor affecting the soil respiration in rainy  and dry seasons  was quite different, which was SW and T10 respectively.
As a consequence, the increase in ecosystem productivity may lead to an increase in carbon turnover in the soil, via an increase in the amount of biomass. But its process and mechanism involving different carbon pools are  very complex, and to measure the soil respiration rate alone can not totally reflect the whole change of carbon cycle. Experiments of further control that involves different carbon pools interaction appending to the measurements of CO2 emission will  help to clarify the relative importance of bulk soil and micro-relationship in the prime effect.        
Soil respiration is the primary way by which CO2 absorbed by terrestrial plants returns to the atmosphere. And it may have distinctly dynamic patterns on  different temporal scales since it is affected by diverse abiotic and biotic factors. Increasing deposition of nitrogen from the traditional cultivation of sympodial bamboos may lead to the sequestration of carbon in vegetation and soil. And the rising temperature and water content may increase the flux of CO2 from the soil, but the response of the ecosystem to simultaneous changes in all of these factors is still unknown. Meanwhile, to provide
abundant supply of bamboo timber, afforestation of  bamboo  species such as Oxytenanthera braunii Pilger ap. Engler, Dendrocalamus brandisii Kurz and Dendrocalamus giganteus Munro is encouraged by the government but without scientific directions. And  unscientific and blind chemical fertilizer application
can be  commonly  in the villages of southwest China. Subsequently, what will happen to the soil structure and how to balance soil nutrient environment under the situation of chemical fertilizer abuse? In the context of climate change, the amount of nitrogen allocated to the soil is predicted to increase with the productivity of terrestrial ecosystem, and may alter soil carbon storage capacities. To provide the proof of soil respiration responding to the nitrogen input for sympodial bamboo afforestation in the beginning period, we set up 4 nitrogen fertilization (CO(NH2)2) levels in mid-high mountain of southeast China, i.e. N0 (calculated by N content), N40, N80, N160 kg/hm2, using the two-year old stump of wine bamboo which is planted every 5 m. The soil respiration rate is measured by using trenching method and infrared gas analyzer. The responding mechanism is discussed through analyzing the change of soil temperature at the depth of 10 cm (T10), as well as changes of soil water-soluble organic carbon content (WSOC) and soil water content (SW). Results show that soil respiration rate is quite different between rainy and dry seasons. The yearly variety of soil respiration rate increases at the end of April or the beginning of May when the rainy reason arrives. Its wave crest arrives in July, Aug. and Sept., and then the rate will decrease all along the dry season-Nov. and Dec. In Feb. and Mar., the trough of soil respiration rate appears. The variety of T10, WSOC and SW are similar  this rule. Exponential function can be used to describe the relationship between T10 and respiration rate. Meanwhile, WSOC or SW has the linear relationship with the respiration rate respectively with the regression test indicting that it is significant. And the temperature sensitivity value Q10 of a whole year is within 2.45-2.78, which is higher than the value of the montane evergreen broad-leaved forest of Ailao mountains nearby. In rainy season, that Q10 decreases within 1.66-1.89 means the sensitivity of respiration rate responding to temperature decreases. On the contrary, Q10 ascends to 4.85-9.54 in dry season specially. The yearly data of WSOC are unstable, but N80 and N160 can elevate WSOC. That Nitrogen input can not enhance T10 and SW explains a majority of varied information of soil respiration under all  treatments. And the main factor affecting the soil respiration in rainy season is SW but in dry season it is T10. As a consequence, the increase in ecosystem productivity may lead, via an increase in the amount of biomass, to an increase in carbon turnover in the soil. But its process and mechanism involving different carbon pools is very complex, and to measure the soil respiration rate alone can not totally reflect the whole change of carbon cycle. Experiments of further control that involves different carbon pools interacting each other appending to the measurements of CO2 emission would help to clarify the relative importance of bulk soil and micro-relationship in the prime effect.    
出版日期: 2013-05-20
CLC:  S 795  
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王树东1
　钟哲科1
李伟成1
2*
　王曙光1
2
　盛海燕3
　郑友苗1

引用本文:

李伟成1,2*,　王曙光1,2，　盛海燕3，　郑友苗1， 王树东1，　钟哲科1. 酒竹人工林土壤呼吸对氮输入的响应及其因子分析[J]. 浙江大学学报(农业与生命科学版), 2013, 39(3): 299-308.

LI Weicheng1,2*, WANG Shuguang1,2, SHENG Haiyan3, ZHENG Youmiao1, WANG Shudong1, ZHONG Zheke1. Effects of nitrogen levels on  soil respiration of sympodial bamboo plantation and factor analysis. Journal of Zhejiang University (Agriculture and Life Sciences), 2013, 39(3): 299-308.

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http://www.zjujournals.com/agr/CN/10.3785/j.issn.1008-9209.2012.07.262    或    http://www.zjujournals.com/agr/CN/Y2013/V39/I3/299

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