새롭게 고안된 Canopy chamber를 이용한 생태계 탄소수지 모니터링 = Carbon Flux Monitoring of Ecosystems Using a Newly Designed Canopy Chamber System

다국어 초록 (Multilingual Abstract)

Current environmental issue is the global warming due to the increasing CO2 concentration in atmosphere. For decelerating the global warming, carbon absorption capacity of terrestrial ecosystems are in the limelight recently. To understand the possibility of ecosystems as a carbon sink, comprehension of carbon flux of ecosystems must be preceded. In an effort to gain insight into the diurnal and seasonal carbon cycle dynamics of ecosystems, newly designed automatic sliding canopy chamber (ASCC) system was constructed at the National Institute of Agricultural Science and Technology, Suwon, Korea. The ASCC system was designed to minimize disturbances to cultivated plants (often referred to as the chamber effect), and also allowed for real-time monitoring. This system could cover a plant canopy, permitting synergistic effects to be monitored. The ASCC system was shaped like a greenhouse: 20m long, 1.8m wide, and 1.4m high, with 5 sectors. Each of the sectors was covered with a sliding cap only at the time of measurement, such that the rest of the time it remained open to the natural environment, in order to remove chamber effects. On the basis of the open-flow method, we had analyzed the differences in CO2 between the air inlet and outlet. Thus, we may estimate the CO2 absorption or CO2 release. In order to verify environmental changes caused by the ASCC system, a verification test was conducted under the field condition in 2005. As for temperature changes owing to the greenhouse effect, less than a 1oC difference was noted in the majority of cases under plant cultivation conditions. In leakage test, it showed a 4.4% leakage (r2 = 0.98**) with ASCC system. On the field test with plant cultivation with barley (Hordeum vulgare), net ecosystem productivity (NEP) and heterotrophic respiration (HR) showed good reflection of diurnal and seasonal variation. After the application of manure treatment (FMT treatment: fertilizer, manure and tillage treatment) to barley, soybean, and red pepper, increases in net primary productivity (NPP) were noted？with the exception of the soybean, in which manure treatment exerted an insignificant effect. As for the increases in NEP and NPP per supplied tonCO2 ha-1, without manure treatment (FT treatment: fertilizer and tillage treatment) caused 3x to 8x increases. As a consequence, soybeans treated with FT treatment evidenced the most profound increases in NEP and NPP. Thus, the most effective method to increase CO2 absorption in plants was the cultivation of soy-beans immediately after barley without manure treatment, and the potential CO2 sequestered from atmosphere was measured at 7.9 tonCO2 ha-1. Overall, the ASCC system is a useful tool for monitoring CO2 flux with minimized disturbance on natural environmental conditions. Also this ASCC system can be applied for study on such as plant growth responses by O3 and various air pollution？NO2, SO2, not only in natural environmental condition but in artificial conditions. Additionally, with regard to the convertibility of the ASCC system into any other ecosystems with transforming frames and of gas analyzer into other greenhouse gas (GHG), the ASCC system can be applied to research on any GHG exchange, and can provide baseline data in a variety of ecosystems. In order to utilize the predictive models for the construction of a national GHG emission inventory in Korea, the accurate monitoring of GHG flux followed by environmental changes is initially required. In this regard, a better understanding of GHG flux and environmental alterations in various ecosystems using the ASCC system could provide the parameters by which the actual measurements and the model equations might be linked for the near future.

국문 초록 (Abstract)

생태계에서의 탄소순환의 일변화와 계절적 변화를 정확한 이해를 위하여 수원 국립농업과학기술원 포장에 장기간 연속 모니터링이 가능한 Automatic Sliding Canopy Chamber(ASCC) 시스템을 제작하였다. ASCC 시스템은 고정 프레임 위를 canopy chamber가 총 5개로 구성되어진 각 섹터를 순차적을 이동, 밀폐시킨 후 측정하는 장비이다. 한 섹터는 20x1.8x1.4m(LxWxH)로 구성되어 섹터 내부에 실제 작물재배 조건과 동일한 작물의 재배가 가능하다. 각 섹터는 측정시간을 제외한 나머지 시간에는 자연환경에 노출되어 있어 작물재배 시 자연환경의 교란을 최소화하였다. 밀폐된 각 섹터의 양 말단에서의 농도차이를 통해 측정된 CO2는 섹터 내부 식물체의 광합성, 호흡량과 토양미생물의 호흡량에 따른 CO2의 배출 또는 흡수량을 의미한다. 장비검증 실험을 통해 canopy chamber 내외부의 온도차이는 작물재배 시 1oC이하였으며, 측정 시 canopy chamber의 밀폐율은 95.6%이었다. 보리(Hordeum vulgare) 전체 재배기간을 통해 측정된 NEP와 HR는 각각의 일변화와 계절적 변이를 잘 반영해 주었으며, 이를 통해 계산된 NPP는 3.0 ton ha-1으로 이는 재배 직후 biomass 측정을 통해 측정된 NPP 2.8 ton ha-1와 유사하였다. 현재 우리나라에서 가장 넓은 재배면적을 차지하며 재배되고 있는 보리, 콩 (Glycine max), 고추 (Capsicum annuum)의 3 종을 선정하여 작물재배 실험을 해 본 결과, 퇴비처리와 미처리구에서의 유의적 차이를 찾을 수 없었던 콩을 제외한 보리와 고추에서 퇴비에 의한 NPP의 증가를 확인할 수 있었다. 공급된 CO2에 따른 NEP와 NPP의 증가는 퇴비 미처리구가 퇴비 처리구보다 최소 3배에서 최대 8배까지 증가하였다. 결과적으로 퇴비를 처리하지 않은 콩의 NEP와 NPP 증가효과가 가장 컸으며, 고추가 그 다음이었다. 경작지에서의 잠재적 CO2 흡수량을 증가시키기 위해서는 보리와 콩을 퇴비를 처리하지 않고 연속하여 재배하는 것이 가장 효과적이었으며 약 7.9 ton ha-1의 CO2가 대기 중으로부터 격리될 것으로 예상된다. 종합하여 보면 ASCC 시스템은 자연환경의 교란을 최소화하며 장기간 연속적인 CO2 모니터링에 있어 매우 효과적이었다. 또한 경작지 뿐만 아니라 다양한 생태계에서도 적용이 가능하며 다양한 가스분석기의 이용으로 CO2 플럭스 뿐만 아니라 다른 온실가스 기체를 대상으로 한 연구에도 유용하게 사용될 것으로 기대된다. 온실가스와 다양한 생태계를 대상으로 한 연구를 통해 축적된 기초자료를 축적할 수 있을 것이며, 이러한 기초자료는 향후 국가온실가스 배출량 인벤토리 산출을 위한 온실가스 배출량 예측 모델 구축에 있어 다양한 환경인자의 변화를 반영할 수 있는 파라메타를 제공할 것으로 기대된다.

목차 (Table of Contents)

• I.Introduction = 1
• II.Historical Review = 4
• A.CO2 flux in natural ecosystems = 4
• B.CO2 flux in agroecosystem = 6
• C.Methods of estimating the amount of CO2 emission = 7
• D.Accumulated soil carbon = 9
• E.Calculation on the national greenhouse emission inventory = 10
• III.Materials and Methods = 12
• A.Composition of ASCC system = 12
• 1.Chamber design = 12
• 2.Timer and valve system = 15
• 3.Pump system = 15
• 4.Chamber operation = 17
• a.Sliding cap operation = 17
• b.NEP measurement = 17
• c.Measurement time = 18
• 5.Heterotrophic respiration = 20
• 6.Chamber environmental conditions = 20
• a.Soil and air temperatures = 22
• b.Soil moisture contents = 22
• c.Solar radiation = 22
• 7.Calculation procedure = 22
• B.Field measurement in plant community = 24
• 1.Experimental site = 24
• 2.Experimental plant species = 24
• a.Barley = 26
• b.Soybean = 27
• c.Red pepper = 28
• 3.Fertilizer treatment and plant growth control = 28
• a.Barley community = 28
• b.Soybean community = 29
• c.Red pepper community = 29
• 4.Biomass and soil carbon measuring = 29
• 5.Data analysis = 30
• IV.Results and Discussions = 31
• A.Application of ASCC on un-plant conditions = 31
• 1.Greenhouse effects = 31
• 2.Light condition = 37
• 3.Leaking test = 40
• B.Application of ASCC on plant community = 42
• 1.Soil moisture contents = 42
• 2.Diurnal changes of NEP and HR = 51
• 3.Seasonal changes of NEP and HR = 55
• C.Manure effect on plants growth = 57
• 1.Manure treatment = 57
• a.Barley community = 57
• b.Soybean community = 65
• c.Red pepper community = 69
• 2.Annual CO2 flux = 73
• 3.CO2 absorption efficiency with FMT treatment = 85
• D.Soil carbon accumulation = 88
• V.Conclusions = 92
• VI.References = 96
• 국문초록 = 105