Eq Ha-1 Research Articles

Energy budgeting and global warming potential of traditional rice production system in Eastern Ghats region of Odisha

Aim: This study aims to focus on traditional agricultural practices which are gaining momentum around the globe as an energy efficient and sustainable approach in the changing climate condition. In this study, an attempt was under taken to quantify the energy use, green house gas emission and global warming potential of rice cultivated by traditional method in terraced low land. Methodology: The data were collected through Focused Group Discussion (FGD) from farmers of the study area using the questionnaire. The sample size was calculated by Neyman method. Results: Total input and output energy required for traditional rice production were 8513.0 MJ ha-1 and 77356.88 MJ ha-1, respectively. Energy use efficiency was calculated as 9.01. Total global warming potential (GWP) was 610.19 CO2 eq ha-1. In this study, the output and input carbon were found to be 2580.48 and 164.75 kg C ha-1, respectively and the carbon efficiency ratio was 15.66. Energy productivity of this traditional method of rice production system was approximately 1.21 to 3.64 times higher than that of other rice production system. Interpretation: Rice is the staple food of tribal's habited in the highland region of Eastern Ghats Odisha, India, and these tribal people mostly cultivate rice by traditional method. This traditional rice production system can be considered as an environmental friendly and sustainable agricultural system in this changing climatic condition, and this system is also economical than the conventional rice cultivation practices. Key words: Budgeting, Energy, Eastern Ghats, Green house gases, Global warming, Rice

Planting and mowing cover crops as livestock feed to synergistically optimize soil properties, economic profit, and environmental burden on pear orchards in the Yangtze River Basin.

Pears, as an important cash crop, are currently facing great issues due to unsustainable management practices. Cover cropping is a sustainable management strategy that can improve soil fertility and increase fruit yield, while it may also stimulate greenhouse gas emissions. Therefore, synergizing multiple indicators to achieve sustainable development is critical. This study introduces a new management system, namely the planting and mowing of ryegrass as a livestock feed system (PRSS), and analyzes its impact on soil quality, economic benefits, and environmental burdens. Our results indicated that PRSS could increase soil pH from 5.08 to 5.48 and decrease the content of soil alkali-hydrolyzable nitrogen, total phosphate, and available phosphate (26.96-59.89%) while also enhancing yield (+38.51%) compared with the traditional natural grass management system (TMS). The average soil methane fluxes in PRSS were 72.67 μg m-2 day-1 , higher than those of TMS (61.28 μg m-2 day-1 ). However, the gross primary production was lower than TMS (-37.24%), and no significant difference was observed in soil nitrous oxide fluxes. In different scenarios, the total profit of PRSS mode 1 (mowing ryegrass and selling to a livestock company) and PRSS mode 2 (mowing ryegrass and feeding own sheep) were 10 706.21 $ ha-1 and 26 592.87 $ ha-1 respectively. These values are respectively2.36 times and 5.85 times higher than that of TMS. The total global warming potential of TMS (18.19 t CO2 -eq ha-1 ) was 1.29 t CO2 -eq ha-1 higher and 2.89 t CO2 -eq ha-1 lower than that of PRSS mode 1 and mode 2 respectively. Compared with traditional natural grass, planting and mowing ryegrass in pear orchards can optimize soil properties, increase fruit yield, and reduce global warming potential. Different modes can greatly increase revenue but have varying impacts on environmental burdens. These findings can help rebuild the links between farmland and specialized livestock production, contributing to sustainable development in the pear industries. © 2023 Society of Chemical Industry.

An Initial Approximation to the Simulation of Soil CO2 Emissions Using the IPCC Methodology in Agricultural Systems of Villavicencio

At a global level, the agricultural sector has represented the largest source of greenhouse gas (GHG) emissions. Our research hypothesizes whether it is possible to faithfully define the effect of soil management factors on modeling soil carbon organic (SOC) sequestration and reducing soil CO2 emissions in different agricultural systems across three zones of Villavicencio (Colombia) by applying the Tier-1 IPCC process‐based model. Agroforestry systems (AFS) are typically found in zone 1, and intensive croplands (CL) in zones 3 and 4. Soil CO2 emissions rates are calculated according to the current IPCC guidelines for national GHG inventories. Root-mean square error (RMSE, RMSE/n), R2, and Nash‐Sutcliffe efficiency (NSE) are measured to assess model performance. In zone 1, 7-year coffee-based agroforestry stored higher SOC, neutralizing -10,83t CO2 eq ha-1 year−1 than 25-year soybean/corn crop rotation in zone 3, with emissions of 2,56t CO2eq ha-1 year-1. The agricultural systems of zones 3 and 4 turned out to be greater emitters, with 7 223 and 3 889t CO2 eq year-1, respectively, which could increase if CL continues to adopt agricultural practices that encourage full tillage. The beneficial effects of AFS on stored SOC are identified via field observations and correctly reproduced by RMSE evaluation.

Potential mitigation of environmental impacts of intensive plum production in southeast China with maintenance of high yields: Evaluation using life cycle assessment.

Intensive plum production usually involves high yields but also high environmental costs due to excessive fertilizer inputs. Quantitative analysis of the environmental effects of plum production is thereby required in the development of optimum strategies to promote sustainable fruit production. We collected survey questionnaires from 254 plum production farms in Zhao'an county, Fujian province, southeast China to assess the environmental impacts by life cycle assessment (LCA) methodology. The farms were categorized into four groups based on yield and environmental impacts, i.e., LL (low yield and low environmental impact), LH (low yield but high environmental impact), HL (high yield but low environmental impact), and HH (high yield and high environmental impact). The environmental impacts, i.e., average energy depletion, global warming, acidification, and eutrophication potential in plum production were 18.17 GJ ha-1, 3.63t CO2 eq ha-1, 42.18kg SO2 eq ha-1, and 25.06kg PO4 eq ha-1, respectively. Only 19.7% of farmers were in the HL group, with 13.3% in the HH group, 39.0% in LL, and 28.0% LH. Plum yields of the HL group were 109-114% higher than the mean value of all 254 farms. Additionally, the HL group had a lower environmental impact per unit area compared to the overall mean value, with a reduction ranging from 31.9% to 36.7%. Furthermore, on a per tonne of plum production basis, the energy depletion, global warming potential, acidification potential, and eutrophication potential of HL farms were lower by 75.4%, 75.0%, 75.6%, and 75.8%, respectively. Overall, the total environmental impact index of LL, LH, HL, and HH groups were 0.26, 0.42, 0.06, and 0.21, respectively. Excessive fertilizer N application was the main source of the environmental impacts, the potential to reduce fertilizer N rate can be achieved without compromising plum yield by studying the HH group. The results provide an important foundation for enhancing the management of plum production, in order to promote 'green' agricultural development by reducing environmental impacts.

Transforming agrifood systems in a win-win for health and environment: evidence from organic rice-duck coculture.

Rice-duck coculture is an ecological agricultural mode; however, the nutritional and environmental benefits of transforming from conventional rice monoculture to rice-duck coculture are unknown. Based on survey data and the life-cycle assessment approach, this study conducted a carbon footprint evaluation of conventional rice monoculture (CR), organic rice monoculture (OR), and organic rice-duck coculture (ORD) using different functional units. The carbon footprint per hectare of ORD (7842 ± 284 kg CO2 eq ha-1 ) was slightly lower than that of CR (7905 ± 412 kg CO2 eq ha-1 ), while higher than that of OR (7786 ± 235 kg CO2 eq ha-1 ). Although the rice yield of ORD was slightly lower than that of CR, its nutrient density unit (NDU) did not decrease significantly due to the additional duck yield. Thus, the carbon footprint per NDU of ORD was significantly lower than that of OR by 24.3% (P < 0.05) and was 5.8% higher than that of CR, but this was not statistically significant. Due to the higher economic profits of ORD, its unit of carbon footprint per economic profit was significantly reduced (by 47.1-75.7%) compared with the other two farming modes, while the net ecosystem economic budget was significantly increased by 98.5-341.9% (P < 0.05). Transforming from a rice monoculture to a coculture system will contribute to a win-win situation for human health and environmental sustainability. This study highlighted the abundant nutritional output function of the rice-duck coculture and analyzed the urgency and necessity of transitioning from traditional agriculture to ecological agriculture from the production and consumption perspectives. © 2022 Society of Chemical Industry.

Economic Analysis of Greenhouse Gas Emission Reduction Potential, Energy-Use and Sustainability of Maize Production in Karnataka

This study was conducted to examine the energy use pattern, efficiency, sustainability and GHG reduction potential in maize production in Karnataka State through a non-parametric production function (DEA) and threshold dynamic panel model framework. Cross-sectional panel data obtained from cost of cultivation scheme was used for the study. The results illustrated that the total input energies in maize production for the period under study increased from 73.01 thousand MJ ha-1in 2010-11 to 95.03 thousand MJha-1in 2017-18. Energy usage pattern indicated that power and electricity consumed for irrigation were the main energy inputs consumed in maize production in the study region. The farmers were technical inefficiency (0.851) implying that 14.9 per cent of the overall resources in the production process could be saved. The total CO2 emission was calculated as 45.17 thousand kg CO2 eq ha-1. By energy optimization, the total energy consumption can be reduced to 105.7 thousand MJ ha-1 corresponding to total CO2 emission reduction potential to value at 5.7 thousand kg CO2eq ha-1. Sustainability of the farm was characterized by positive growth at a low rate of 0.07% per annum and thus, higher efficiency level accompanied by high level of productivity resulted in potential reduction emission level among the farmers. It is, therefore; recommended that government policies should be geared towards practices that tend to improve efficiency and productivity of the farmers through effective extension education.

Growth and Development of Groundnut (Arachis hypogaea L.) as Influenced by Different Levels and Timing of Phosphogypsum Nutrition

Aims: A field experiment entitled “Growth and development of groundnut (Arachis hypogaea L.) as influenced by different levels and timing of phosphogypsum nutrition” was planned to ascertain the role of phosphogypsum an industrial by product in promoting growth of groundnut.&#x0D; Study Design: Experiment was carried out at Agronomy field unit, Zonal Agricultural Research Station, University of Agricultural Sciences, GKVK, Bangalore, during kharif 2019. Experiment was planned with eleven treatments of which eight received sulphur through phosphogypsum at different levels (50, 75, 100 and 125 kg S eq ha-1) as basal and split (30 DAS) and one through gypsum (500 kg ha-1) as basal. Whereas, other two treatments with NPK and NK alone are included for comparison. Design of the experiment is RCBD with eleven treatments replicated thrice.&#x0D; Results: Among different treatments, application of phosphogypsum 125 kg S eq ha-1 in split recorded highest growth parameters like plant height (42.49 cm), leaf area (1137 cm2 plant-1), dry matter per plant (29.30 g) and number of branches plant‑1 (8.62). Whereas, application of phosphogypsum 100 kg S eq ha‑1 in split found on par with 125 kg with respect to all growth parameters. While lowest values of all the parameters were noticed in treatment receiving N and K fertilizer alone.

Greenhouse gas emissions and mitigation potential of hybrid maize seed production in northwestern China

Although hybrid maize seed production is one of the most important agriculture systems worldwide, its greenhouse gas (GHG) emissions and potential mitigation measures have not been studied. In this study, we used life cycle assessment (LCA) to quantify the GHG emissions of 150 farmers run by 6 companies in an area of northwest China known for hybrid maize seed production. The results indicated that the average reactive nitrogen (Nr) losses and GHG emissions from hybrid maize seed production were 53 kg N ha-1 and 8077 kg CO2 eq ha-1, respectively. Furthermore, the average nitrogen and carbon footprints of the process were 12.2 kg N Mg-1 and 1495 kg CO2 eq Mg-1, respectively. Nitrogen fertilizer and electricity consumption for irrigation were the main contributors to high GHG emissions, accounting for 60% and 30% of the total, respectively. The GHG emissions from seed production for different companies varied greatly with their resource input. There was also a large variation in environmental burdens among the 150 farmers. Based on an analysis of the yield group, we found that the carbon footprint of the first group (the one with the highest yield) was 27% lower than the overall average. Scenario analysis suggests that a combined reduction of N input rate, optimizing irrigation, and increasing yield can eventually mitigate the carbon footprint of hybrid maize seed production by 37%. An integrated systematic approach (e.g., ISSM: integrated soil-crop system management) can reduce the GHG emissions involved in producing hybrid maize seeds. This study provides quantitative evidence and a potential strategy for GHG emissions reduction of hybrid maize seed production.

Response of Groundnut (Arachis hypogaea L.) to Different Levels and Time of Phosphogypsum Nutrition

Background: Groundnut is one of the most important oilseed crops of India. Improving productivity of groundnut to meet the domestic vegetable oil demand through balanced fertilization is the prime challenge lying before the agronomists in the country. With the aim of evaluating phosphogypsum as a source of sulphur nutrition in groundnut, a field experiment entitled “Response of groundnut (Arachis hypogaea L.) to different levels and time of phosphogypsum nutrition” was conducted at Agronomy field unit, University of Agricultural Sciences Bangalore, during kharif-2019. Methods: Experiment was laid out in randomised complete block design (RCBD) with eleven treatments, of which eight have different combinations of phosphogypsum applied as basal and in split (30 DAS) and one with gypsum as basal alone. Whereas, the remaining two treatments, without any additional source of sulphur are included for comparison. Result: Among eleven treatments, application of phosphogypsum @ 125 kg S eq ha-1 in split recorded highest yield attributes, pod yield (2063 kg ha-1), kernel yield (1418 kg ha-1) and sulphur uptake (11.33 kg ha-1). Which were on par with 100 kg S eq ha-1 in split (2014, 1380 and 10.39 kg ha-1, respectively). All other treatments recorded lower values with lowest in treatments without any additional sulphur source.

Can cropland management practices lower net greenhouse emissions without compromising yield?

Smart cropland management practices can mitigate greenhouse gas (GHG) emissions while safeguarding food security. However, the integrated effects on net greenhouse gas budget (NGHGB) and grain yield from different management practices remain poorly defined and vary with environmental and application conditions. Here, we conducted a global meta-analysis on 347 observation sets of non-CO2 GHG (CH4 and N2 O) emissions and grain yield, and 412 observations of soil organic carbon sequestration rate (SOCSR). Our results show that for paddy rice, replacing synthetic nitrogen at the rate of 30%-59% with organic fertilizer significantly decreased net GHG emissions (NGHGB: -15.3±3.4 [standard error], SOCSR: -15.8±3.8, non-CO2 GHGs: 0.6±0.1 in Mg CO2 eq ha-1 year-1 ) and improved rice yield (0.4±0.1 in Mg ha-1 year-1 ). In contrast, intermittent irrigation significantly increased net GHG emissions by 11.2±3.1 and decreased rice yield by 0.4±0.1. The reduction in SOC sequestration by intermittent irrigation (15.5±3.3), which was most severe (>20) in alkaline soils (pH>7.5), completely offset the mitigation in CH4 emissions. Straw return for paddy rice also led to a net increase in GHG emissions (NGHGB: 4.8±1.4) in silt-loam soils, where CH4 emissions (6.3±1.3) were greatly stimulated. For upland cropping systems, mostly by enhancing SOC sequestration, straw return (NGHGB: -3.4±0.8, yield: -0.5±0.6) and no-tillage (NGHGB: -2.9±0.7, yield: -0.1±0.3) were more effective in warm climates. This study highlights the importance of carefully managing croplands to sequester SOC without sacrifice in yield while limiting CH4 emissions from rice paddies.

Conversion of coastal wetlands, riparian wetlands, and peatlands increases greenhouse gas emissions: A global meta-analysis.

Land-use/land-cover change (LULCC) often results in degradation of natural wetlands and affects the dynamics of greenhouse gases (GHGs). However, the magnitude of changes in GHG emissions from wetlands undergoing various LULCC types remains unclear. We conducted a global meta-analysis with a database of 209 sites to examine the effects of LULCC types of constructed wetlands (CWs), croplands (CLs), aquaculture ponds (APs), drained wetlands (DWs), and pastures (PASs) on the variability in CO2 , CH4 , and N2 O emissions from the natural coastal wetlands, riparian wetlands, and peatlands. Our results showed that the natural wetlands were net sinks of atmospheric CO2 and net sources of CH4 and N2 O, exhibiting the capacity to mitigate greenhouse effects due to negative comprehensive global warming potentials (GWPs; -0.9 to -8.7 t CO2 -eqha-1 year-1 ). Relative to the natural wetlands, all LULCC types (except CWs from coastal wetlands) decreased the net CO2 uptake by 69.7%-456.6%, due to a higher increase in ecosystem respiration relative to slight changes in gross primary production. The CWs and APs significantly increased the CH4 emissions compared to those of the coastal wetlands. All LULCC types associated with the riparian wetlands significantly decreased the CH4 emissions. When the peatlands were converted to the PASs, the CH4 emissions significantly increased. The CLs, as well as DWs from peatlands, significantly increased the N2 O emissions in the natural wetlands. As a result, all LULCC types (except PASs from riparian wetlands) led to remarkably higher GWPs by 65.4%-2,948.8%, compared to those of the natural wetlands. The variability in GHG fluxes with LULCC was mainly sensitive to changes in soil water content, water table, salinity, soil nitrogen content, soil pH, and bulk density. This study highlights the significant role of LULCC in increasing comprehensive GHG emissions from global natural wetlands, and our results are useful for improving future models and manipulative experiments.

A critical review of the impacts of cover crops on nitrogen leaching, net greenhouse gas balance and crop productivity.

Cover crops play an increasingly important role in improving soil quality, reducing agricultural inputs and improving environmental sustainability. The main objectives of this critical global review and systematic analysis were to assess cover crop practices in the context of their impacts on nitrogen leaching, net greenhouse gas balances (NGHGB) and crop productivity. Only studies that investigated the impacts of cover crops and measured one or a combination of nitrogen leaching, soil organic carbon (SOC), nitrous oxide (N2O), grain yield and nitrogen in grain of primary crop, and had a control treatment were included in the analysis. Long‐term studies were uncommon, with most data coming from studies lasting 2–3 years. The literature search resulted in 106 studies carried out at 372 sites and covering different countries, climatic zones and management. Our analysis demonstrates that cover crops significantly (p < 0.001) decreased N leaching and significantly (p < 0.001) increased SOC sequestration without having significant (p > 0.05) effects on direct N2O emissions. Cover crops could mitigate the NGHGB by 2.06 ± 2.10 Mg CO2‐eq ha−1 year−1. One of the potential disadvantages of cover crops identified was the reduction in grain yield of the primary crop by ≈4%, compared to the control treatment. This drawback could be avoided by selecting mixed cover crops with a range of legumes and non‐legumes, which increased the yield by ≈13%. These advantages of cover crops justify their widespread adoption. However, management practices in relation to cover crops will need to be adapted to specific soil, management and regional climatic conditions.

Land use of drained peatlands: Greenhouse gas fluxes, plant production, and economics.

Drained peatlands are hotspots for greenhouse gas (GHG) emissions, which could be mitigated by rewetting and land use change. We performed an ecological/economic analysis of rewetting drained fertile peatlands in a hemiboreal climate using different land use strategies over 80years. Vegetation, soil processes, and total GHG emissions were modeled using the CoupModel for four scenarios: (1) business as usual-Norway spruce with average soil water table of -40cm; (2) willow with groundwater at -20cm; (3) reed canary grass with groundwater at -10cm; and (4) a fully rewetted peatland. The predictions were based on previous model calibrations with several high-resolution datasets consisting of water, heat, carbon, and nitrogen cycling. Spruce growth was calibrated by tree-ring data that extended the time period covered. The GHG balance of four scenarios, including vegetation and soil, were 4.7, 7.1, 9.1, and 6.2 Mg CO2 eq ha-1 year-1 , respectively. The total soil emissions (including litter and peat respiration CO2 + N2 O + CH4 ) were 33.1, 19.3, 15.3, and 11.0 Mg CO2 eq ha-1 year-1 , respectively, of which the peat loss contributed 35%, 24%, and 7% of the soil emissions for the three drained scenarios, respectively. No peat was lost for the wet peatland. It was also found that draining increases vegetation growth, but not as drastically as peat respiration does. The cost-benefit analysis (CBA) is sensitive to time frame, discount rate, and carbon price. Our results indicate that the net benefit was greater with a somewhat higher soil water table and when the peatland was vegetated with willow and reed canary grass (Scenarios 2 and 3). We conclude that saving peat and avoiding methane release using fairly wet conditions can significantly reduce GHG emissions, and that this strategy should be considered for land use planning and policy-making.

An Analysis of the Climate Change Mitigation Potential through Soil Organic Carbon Sequestration in a Corn Belt Watershed.

Land-based carbon sequestration constitutes a major low cost and immediately viable option in climate change mitigation. Using downscaled data from eight atmosphere-ocean general circulation models for a simulation period between 2015 and 2099, we examine the carbon sequestration potential of alternative agricultural land uses in an intensively farmed Corn Belt watershed and the impact of climate change on crop yields. Our results show that switching from conventional tillage continuous corn to no-till corn-soybean can sequester the equivalent of 192.1 MtCO2 eq of soil organic carbon per hectare with a sequestration rate of 2.26 MtCO2 eq ha-1 yr-1. Our results also indicate that switchgrass can sequester the equivalent of 310.7 MtCO2 eq of soil organic carbon per hectare with a sequestration rate of 3.65 MtCO2 eq ha-1 yr-1. Our findings suggest that, unlike for corn and soybean yields, climate change does not have a significant effect on switchgrass yields, possibly due to the carbon fertilization effect.

Tropical Peat Swamp Management Options: A Case Study Using System Dynamic in Southern Aceh

Tropical peat forest ecosystems have multiple benefits as regulating hydrological system, carbon storage, timber and non-timber products, and protecting the biodiversity. Lack of understanding of these functions, short-term economic benefits is more preferable despite reducing its ecological benefits. This study proposed a system dynamics model of tropical peat forest ecosystem in determining its optimum management for extractive utilizations (timber and non-timber forest products), environmental services, and biodiversity. A dynamics model was used to describe changes in peatland and forest cover, biomass accumulation and carbon storage, and total economic value of tropical peat forest ecosystem in Trumon and Singkil, Southern Aceh. The projection showed that peat forest ecosystem benefits would decline in the long term if degradations continue at the same rate over last decade. Efforts to change the primary peat forest to plantation would reduce the total economic value of ecosystem and biodiversity values at level -19.63% and -26.28% from current conditions. Carbon emissions were increased at 117.32 tons CO2 eq ha-1 year-1, higher than average of carbon losses from peatland oxidation. Preserving 50% of forest vegetation on moderate depth and protection very deep peatlands would reduce emission -6.96% to -35.06% and increase forest carbon storage at significant rate +15.06% to +63.32%, respectively. These mitigation schemes would improve the biodiversity and hydrological function. Forest rehabilitation with agroforestry practices will enhance carbon uptake, especially on degraded lands.

Equação de biomassa e estoque de carbono do pinhão manso, no município de Viçosa, MG

O presente trabalho teve como objetivo estimar equações de biomassa e o estoque de carbono da cultura do Pinhão Manso (Jatrophacurcas L.). A área estudada localiza-se no município de Viçosa, MG. O plantio foi realizado em espaçamento 3,5x3,0m, em 4,64ha. Para quantificação da biomassa, foi utilizado o método direto e destrutivo, aplicado às árvores-amostra, que foram selecionadas de acordo com as medidas da altura, do diâmetro das copas e do número de ramos. A determinação da biomassa de cada árvore foi obtida pelo método da proporcionalidade. Os modelos testados foram adaptados de Spurr e de Schumacher &amp; Hall, para biomassa aérea e biomassa total (biomassa aérea mais biomassa de raízes pivotantes). O estoque de carbono foi estimado através da multiplicação da biomassa seca pelo teor de carbono da matéria seca, que foi obtido pelo método da calcinação em mufla. A estimativa do CO2 equivalente estocado foi obtida pela multiplicação do estoque de carbono pelo fator 44/12. A equação que obteve melhor ajuste e que foi utilizada para determinação do estoque de carbono deste estudo foi a de Spurr, com os dados de biomassa total, B=0,7601*(DC2*H)0,8949, em que B = biomassa (kg); DC = diâmetro de copa (m); e H = altura (m). O estoque de carbono encontrado da cultura, no quarto ano, foi de 6,79MgC ha-1, correspondendo a 24,89Mg CO2(eq) ha-1. Os resultados mostram que o pinhão-manso é ambientalmente viável para elaboração de projetos MDL de florestamento/reflorestamento ou em projetos de carbono para mercados voluntários, agregando renda ao produtor rural e melhorando a atratividade financeira da cultura.

Il calcolo dei crediti di carbonio: il modello CO2FIX v. 3.1 applicato ad una faggeta sotto Forest Management nel sud Italia

Abstract: Forests play an important role in the mitigation of the effects of climate change thanks to their ability to sequestrate carbon dioxide from atmosphere. The assessment of the carbon fixed by forest ecosystems (stocks) and the carbon accumulated over a period of time (sinks) is focal for environmental protection scopes, as well as for accessing the carbon credits market. The main purpose of this work was to estimate (using the ecosystem-level model CO2FIX v. 3.1) the equivalent carbon dioxide (Mg CO2 eq ha-1 y-1) fixed by a beech stand located in southern Italy during the First Commitment Period (2008-2012) under Forest Management (art. 3.4 of the Kyoto Protocol). The model was applied over a forest district using local data obtained from both literature and field analysis. Over the simulated period, sink values of 9.77 Mg C ha-1 (1.95 ± 0.91 Mg C ha-1 y-1 on average) were obtained, corresponding to an accountable value of 5.36 Mg CO2 eq ha-1 and according to the possibility to accredit only the 15% of the real value (Decision 16/CMP.1 UNFCCC). Sink values estimated with the model applied barely diverge from those obtained by similar studies on beech forests, that have been briefly reviewed and discussed here.

Estimation of Critical Loads of. Sulfur and Nitrogen for the Korean Ecosystem

The critical loads of sulfur and nitrogen and their exceedances by the sulfur and nitrogen deposition of 1994-1998 were mapped for South Korea for the first time with a spatial resolution of 11km×14km (0.12 5° Long.×0.125° Lat.) using the steady-state mass balance model. The Korean soil and geological maps with the map scale of 1: 250, 000 and the Korean forestry statistical yearbooks were used as basis for the estimations of weathering rate of base cations, critical alkalinity leaching, denitrification fraction and uptakes of base cation and nitrogen. Wet depositions of sulfur, nitrogen and non-sea-salt base cations were derived from measured concentrations in precipitation and precipitation rates using optimum regression equations while dry depositions of sulfur and base cations were estimated using the inferential method. However, dry deposition of nitrogen due to NO, NO2, NH3 and NH4+ species was estimated using the MM5 numerical model, a modified Regional Acid deposition Model (RADM) and the K-mean clustering technique using three consecutive days of gridded daily mean 850 hPa geopotential height fields without precipitation on the last day over South Korea for 5 years. The predominant ranges of base cation deposition, weathering and uptake were estimated to be 300-500 eq ha-1 yr-1, 200-500 eq ha-1 yr-1 and 200-400 eq ha-1 yr-1, respectively. Critical alkalinity leaching was mainly in the range of 1, 0002, 000 eq ha-1 yr-1. Consequently, a large percentage of the maximum critical load of sulfur was found to be in the range of 1, 0002, 000 eq ha-1 yr-1. The estimated predominant ranges of nitrogen immobilization and uptake were 120-180 eq ha-1 yr-1 and 300-400 eq ha-1 yr-1, respectively, indicating low values of the minimum critical load of nitrogen. The maximum critical load of nitrogen was found to be relatively high (predominantly 2, 0004, 000 eq ha-1 yr-1) while the critical load of nutrient nitrogen was low (predominantly 400-800 eq ha-1 yr-1). Exceedance of the maximum critical load of sulfur was found at 85% of the Korean ecosystems considered mainly in the southeastern part of Korea, whereas that of the critical load of nutrient nitrogen was found in the whole Korean ecosystems. This implies that Korean ecosystems are very susceptible to the combined loadings of sulfur and nitrogen.

Critical loads of acidity for forest soils: Tentative modifications

We reviewed the current methods for calculatingcritical loads of acidity for forest soils. The consequencesof four sets of assumptions concerning the soil modelstructure, parameter values and the critical loads criterionwere explored by comparing the values of the averageaccumulated exceedance (AAE) calculated for Finland withdeposition values for the year 1995. The AAE index is given inthe unit of deposition and is a measure of how far a region isfrom being protected in terms of fulfilling a certaincriterion, taking into account the size of the ecosystem areas.Using a critical limit for the molar ratio of theconcentrations of base cations to aluminium in soil solutiongave the lowest average accumulated exceedance. Assumingorgano-aluminium complexes and leaching of organic anions gaveAAE = 4 eq ha-1 a-1, which was close to the valueobtained with the standard approach used in Finland, assuminggibbsite equilibrium and no leaching of organic anions,yielding AAE = 5 eq ha-1 a-1. With a critical basesaturation limit, instead of the concentrations criterion, theAAE index was 17 eq ha-1 a-1. The highest averageaccumulated exceedance (AAE = 25 eq ha-1 a-1),corresponding to the lowest critical load, was obtained whenthe effects-based criterion (critical concentration or criticalbase saturation) was substituted with one restricting thedeterioration of the neutralizing capacity of the soil, ANCle(crit) = 0. These tests illustrate the variabilityof the critical load values for acidity that can be introducedby changing the criterion or by varying the calculation method,without, however, representing the extreme values of criticalloads that could be derived.

Sulfur Acidity Loading in South Korean Ecosystems

The applicability of critical load (CL) methodology for thedetermination of natural terrestrial ecosystem sensitivity to sulfur acidity loading in South Korea was investigated.The sulfur critical load values, CLmaxS, were calculated for the terrestrial ecosystems of South Korea using the steady-state mass balance approach. The corresponding mapping of CLmaxS was carried out on the scale of 11 × 14 km grid cells. The estimated CLmaxS values depend on the low rate of soil chemical base cation weathering (mainly, 200–400 eq ha-1 yr-1), relativelylow base cation depositions (mainly less than 450 eq ha-1 yr-1) and base cation uptake (predominantly 300–400 eq ha-1 yr-1), and in significant degree on high valuesof acid neutralizing capacity. The latter in turn is connectedwith relatively high values of surface runoff (maximum 9000 m3 ha-1 yr-1). It has been shown that about 75%of CLmaxS values are in the range of 1000–2000 eq ha-1 yr-1 and about 15% are relatively low values(<1000 eq ha-1 yr-1). About 10% of ecosystems haveCL values more than 2000 eq ha-1 yr-1. The sensitiveand very sensitive ecosystems occur in the southeastern part of the country whereas the sustainable ecosystems are wide spread in the northeastern part. In accordance with sulfur critical load and sulfur deposition patterns, in 1994–1997 the CLmaxS values were found to be exceeded in about 40% of total number of Korean ecosystems, mainly in the southeastern part of the country. The average yearly valuesof exceedances varied from 176 to 3100 eq ha-1 yr-1.