• Authors:
    • Husnain,H.
    • Wigena,I. G. P.
    • Dariah,A.
    • Marwanto,S.
    • Setyanto,P.
    • Agus,F.
  • Source: Mitigation and Adaption Strategies for Global Change
  • Volume: 19
  • Issue: 6
  • Year: 2014
  • Summary: With the increasing use of tropical peatland for agricultural development, documentation of the rate of carbon dioxide (CO 2) emissions is becoming important for national greenhouse gas inventories. The objective of this study was to evaluate soil-surface CO 2 fluxes from drained peat under different land-use systems in Riau and Jambi Provinces, Sumatra, Indonesia. Increase of CO 2 concentration was tracked in measurement chambers using an Infrared Gas Analyzer (IRGA, LI-COR 820 model). The results showed that CO 2 flux under oil palm ( Elaeis guineensis) plantations ranged from 3416 and 4525 Mg CO 2 ha -1 year -1 in two locations in Jambi province to 6625 Mg CO 2 ha -1 year -1 for a site in Riau. For adjacent plots within 3.2 km in the Kampar Peninsula, Riau, CO2 fluxes from an oil palm plantation, an Acacia plantation, a secondary forest and a rubber plantation were 6625, 5919, 6125, 5217 Mg ha -1 year -1, respectively, while on bare land sites it was between 5630 and 6724 Mg CO 2 ha -1 year -1, indicating no significant differences among the different land-use systems in the same landscape. Unexplained site variation seems to dominate over land use in influencing CO 2 flux. CO 2 fluxes varied with time of day ( p<0.001) with the noon flux as the highest, suggesting an overestimate of the mean flux values with the absence of night-time measurements. In general, CO 2 flux increased with the depth of water table, suggesting the importance of keeping the peat as wet as possible.
  • Authors:
    • Utomo,M.
  • Source: Sustainable Living with Environmental Risks
  • Volume: 9784431548041
  • Year: 2014
  • Summary: Global warming due to greenhouse gas emissions is currently receiving considerable attention worldwide. Agricultural systems contribute up to 20 % of this global warming. However, agriculture can reduce its own emissions while increasing carbon sequestration through use of recommended management practices, such as consernvation tillage (CT). The objective of this paper is to review the role of long-term CT in mitigating greenhouse gas emissions during corn production in rainfed tropical agro-ecosystems. The types of conservation tillage were no-tillage (NT) and minimum tillage (MT). In a long-term plot study, CO2 emission from CT throughout the corn season was consistently lower than that from intensive tillage (IT). The cumulative CO2 emissions of NT, MT, and IT in corn crops were 1.0, 1.5, and 2.0 Mg CO2-C ha-1season-1, respectively. Soil carbon storage at 0-20 cm depth after 23 years of NT cropping was 36.4 Mg C ha-1, or 43 % and 20 % higher than the soil carbon strorage of IT and MT, respectively. Thus, NT had sequestered some 4.4 Mg C ha-1of carbon amounting to carbon sequestration rate of 0.2 Mg C ha-1 year-1. IT, on the other hand, had depleted soil carbon by as much as 6.6 Mg C ha-1, yielding a carbon depletion rate of 0.3 Mg C ha-1 year-1. Assessment of the farmer's corn fields confirmed these findings. CO2 emission from CT corn farming was similar to that of rubber agroforest and lower than IT corn farming. Based on carbon balance analysis, it can be concluded that corn crops in tropical rainfed agro-ecosystems were not in fact net emitters, and that NT was a better net sinker than other tillage methods. © 2014 The Editor(s) (if applicable) and the Author(s). All rights reserved.
  • Authors:
    • Fanin,Nicolas
    • Haettenschwiler,Stephan
    • Fromin,Nathalie
  • Source: Plain and Soil
  • Volume: 379
  • Issue: 1-2
  • Year: 2014
  • Summary: Little is known about how plant leaf litter decomposing on the soil surface is affecting microbial communities in the underlying soil. Here we examined the effects of decomposing leaf litter of different initial chemistry on biomass, stoichiometry, community structure and activity of microorganisms in the soil underneath the decaying litter layer. Leaf litter from six different neotropical tree species with contrasted quality decomposed on top of a common tropical soil in a laboratory microcosm experiment over 98 days. At the end of the experiment we determined microbial biomass C, N, and P, microbial community structure (PLFA), and community level physiological profiles (CLPP) from the top soil. Despite growing in a common soil substrate, soil microorganisms were strongly affected by litter species, especially by the soluble litter fraction. While litters with low soluble C content did not affect the soil microbial community, litters with high soluble C content led to an increase of microbial biomass and to a structural shift to relatively more Gram-negative bacteria. Changing community structure resulted in changes of catabolic capacity of microorganisms to metabolize a range of different C substrates. The large differences in leachate N and P among litter species, in contrast, had no effect on soil microbial parameters. Our data suggest that plant litter decomposing on the soil surface exhibit a strong and predictable leachate C-control over microbial community biomass, structure and function in the underlying soil.
  • Authors:
    • Thompson, A.
    • Chadwick, O. A.
    • Kramer, M. G.
    • Buettner, S. W.
  • Source: Journal
  • Volume: 221
  • Year: 2014
  • Summary: The transport of organic carbon (C) to deep mineral horizons in soils can lead to long-term C stabilization. In basaltic soils, C associations with short-range-ordered (SRO) minerals often lead to colloid-sized aggregates that can be dispersed and mobilized by changes in soil solution chemistry. In the montane forest region of Hawaii, basaltic soils are exposed to high rainfall and anoxic conditions that facilitate ferric (Fe-III) (oxyhydr)oxide reduction. We explored the potential of iron (Fe)-reducing conditions to mobilize C by exposing the surface mineral horizons of three soils from the Island of Hawai'i (aged 03, 20, and 350 ky) to 21 days of anoxic incubation in 1:10 soil slurries. Mobilized C was quantified by fractionating the slurries into three particle-size classes (<430 nm,<60 nm,<23 nm approximate to 10 kDa). In all three soils, we found Fe reduction (maximum Fe2+ (aq) concentration approximate to 17.7 +/- 1.9 mmol kg(-1) soil) resulted in similar to 500% and similar to 700% increase of C in the 23-430 nm, and <23 nm size fractions, respectively. In addition, Fe reduction increased solution ionic strength by 127 mu S cm(-1) and generated hydroxyl ions sufficient to increase the slurry pH by one unit. We compared this to C mobilized from the slurries during a 2-h oxic incubation across a similar range of pH and ionic strength and found smaller amounts of dissolved (<23 nm) and colloidal (23-430 nm) C were mobilized relative to the Fe reduction treatments (p < 0.05). In particular, C associated with the largest particles (60-430 nm) was dispersed almost exclusively during the Fe reduction experiments, suggesting that it had been bound to Feoxide phases. Our experiments suggest that colloidal dispersion during Fe-reducing conditions mobilizes high concentrations of C, which may explain how C migrates to deep mineral horizons in redox dynamic soils. (C) 2014 Elsevier B.V. All rights reserved.
  • Authors:
    • Jair Andrade, H.
    • Alvarado, J.
    • Segura, M.
  • Source: Revista Colombia Forestal
  • Volume: 16
  • Issue: 1
  • Year: 2013
  • Summary: The increase in greenhouse gas emissions from anthropogenic sources has resulted in climate change, which affects all living beings. Coffee (Coffea arabica L.) plantations, in monoculture or together with timber species such as salmwood (Cordia alliodora), mitigate climate change due to fixation of atmospheric CO 2 that is deposited in biomass and soils. This study was carried out in the municipality of Libano, Tolima, Colombia with the objective of defining which of the following coffee production systems store more soil organic carbon (SOC): (1) monoculture, (2) agroforestry systems (AFS) with salmwood, and (3) AFS with plantain. Farms with those systems that are the most dominant in the study zone were selected. From each system, five repetitions were identified to be analyzed with a completely randomized design. In each plot or repetition, five samples for bulk density (BD) using the cylinder method and a composite sample for concentration of SOC were taken and analyzed using the Walkley and Black approach. The systems of production did not significantly (p >0.05) affect either the BD or the concentration of SOC. However, AFS with plantain tended to have less BD than monoculture and AFS with salmwood (0.830.03 vs 0.880.03 vs 0.920.04 g.cm -3, respectively). These systems of production stored between 50 and 54 t.ha -1 of SOC in the top 30 cm, which indicates their capacity for climate change mitigation.
  • Authors:
    • Cerri, C. E. P.
    • Soares-Filho, B.
    • Galford, G. L.
  • Source: Philosophical Transactions of the Royal Society B, Biological Sciences
  • Volume: 368
  • Issue: 1619
  • Year: 2013
  • Summary: The Brazilian Amazon frontier shows how remarkable leadership can work towards increased agricultural productivity and environmental sustainability without new greenhouse gas emissions. This is due to initiatives among various stakeholders, including national and state government and agents, farmers, consumers, funding agencies and non-governmental organizations. Change has come both from bottom-up and top-down actions of these stakeholders, providing leadership, financing and monitoring to foster environmental sustainability and agricultural growth. Goals to reduce greenhouse gas emissions from land-cover and land-use change in Brazil are being achieved through a multi-tiered approach that includes policies to reduce deforestation and initiatives for forest restoration, as well as increased and diversified agricultural production, intensified ranching and innovations in agricultural management. Here, we address opportunities for the Brazilian Amazon in working towards low-carbon rural development and environmentally sustainable landscapes.
  • Authors:
    • Gonzalez, A.
    • Tapasco, J.
    • Graefe, S.
  • Source: Fruits
  • Volume: 68
  • Issue: 4
  • Year: 2013
  • Summary: Introduction. The cultivation of high-value fruit species is a profitable agricultural activity in many tropical countries; however, intensive fruit cultivation may depend on high amounts of external inputs. The objective of our study was to quantify and compare the resource use during the cultivation of eight tropical fruit species (Rubus glaucus, Solanum quitoense, Passiflora edulis, Cyphomandra betacea, Physalis peruviana, Ananas comosus, Persea americana and Mangifera indica) commonly cultivated in Colombia. It further aimed to identify greenhouse gas (GHG) emissions in the selected production systems and to highlight the potential to contribute to climate change mitigation efforts. Materials and methods. The analysis was based on data from agricultural databases and applied a life-cycle assessment with energy use and GHG emissions as impact categories. Furthermore, economic indicators were taken into account with the aim of integrating the environmental and economic goals of production systems. Results and discussion. Among the eight fruit species studied, mango (Mangifera indica) was found to have the lowest and tree tomato (Cyphomandra betacea) the highest emission profile. The variability in resource use among growers of the same species was high, indicating the need to improve management abilities at the farm level. Mineral fertilizer production was the highest contributor to GHG emissions. GHG- and energy-efficient management alternatives would have a high potential to reduce the carbon footprint of fruit cultivation.
  • Authors:
    • Meyer-Aurich, A.
    • Salleh, M. A. M.
    • Hansen, A.
    • Lau, Lek H.
    • Grundman, P.
    • Harsono, S. S.
    • Idris, A.
    • Ghazi, T. I. M.
  • Source: Resources, Conservation and Recycling
  • Volume: 77
  • Year: 2013
  • Summary: This paper presents results from a gate-to-gate analysis of the energy balance, greenhouse gas (GHG) emissions and economic efficiency of biochar production from palm oil empty fruit bunches (EFB). The analysis is based on data obtained from EFB combustion in a slow pyrolysis plant in Selangor, Malaysia. The outputs of the slow pyrolysis plant are biochar, syngas, bio-oil and water vapor. The net energy yield of the biochar produced in the Selangor plant is 11.47 MJ kg(-1) EFB. The energy content of the biochar produced is higher than the energy required for producing the biochar, i.e. the energy balance of biochar production is positive. The combustion of EFB using diesel fuel has the largest energy demand of 2.31 MJ kg(-1) EFB in the pyrolysis process. Comparatively smaller amounts of energy are required as electricity (0.39 MJ kg(-1) EFB) and for transportation of biochar to the warehouse and the field (0.13 MJ kg(-1) EFB). The net greenhouse gas emissions of the studied biochar production account for 0.046 kg CO2-equiv.kg(-1) EFB yr(-1) without considering fertilizer substitution effects and carbon accumulation from biochar in the soil. The studied biochar production is profitable where biochar can be sold for at least 533 US-$t(-1). Potential measures for improvement are discussed, including higher productivity of biochar production, reduced energy consumption and efficient use of the byproducts from the slow pyrolysis.
  • Authors:
    • Annandale, J. G.
    • Van Asten,P. J. A.
    • Uzayisenga, B.
    • Swennen, R.
    • Blomme, G.
    • Vanlauwe, B.
    • Ndabamenye, T.
    • Barnard, R. O.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 95
  • Issue: 2
  • Year: 2013
  • Summary: The productivity of East African highland (EAH) banana cropping systems is declining, particularly in areas with low inherent soil fertility. Soil fertility management requires knowledge of nutrient flows at the interface between the soil surface and the soil system. The magnitude of soil fertility dynamics and nutrient depletion was studied for a short-term banana plant density trial in three contrasting agro-ecological sites of Rwanda (Kibungo low rainfall with medium soil fertility, Rubona high rainfall with low soil fertility and Ruhengeri high rainfall with high soil fertility) using nutrient stock and partial nutrient balance calculations. Plant density did not influence significantly nutrient mass fractions in plant parts (fruit, leaves and pseudostems) but nutrients contained through shredded leaves and pseudostems and those removed through bunch dry matter increased with plant density. Plant density responses to variation in soil fertility and partial nutrient balances seemed to depend on diversity in climate and soil type. Partial N and K balances (kg ha(-1) year(-1)) were estimated to be strongly negative at Rubona and Ruhengeri while Ca and Mg were positive at Kibungo and Ruhengeri but negative at Rubona. This study showed that partial nutrient balances associated with soil nutrient stocks can provide the first order of magnitude of nutrient depletion in low input EAH banana cropping systems. This brings attention from agricultural researchers and farmers to develop options that can improve the productivity of these systems, where resource availability for improved nutrient management is scarce.
  • Authors:
    • Say, E.
    • Astorga, C.
    • Poveda, V.
    • Alvarado, E.
    • Avila, G.
    • Mavisoy, H.
    • Espin, T.
    • Davila, H.
    • Cifuentes, M.
    • Orozco, L.
    • Cerda, R.
    • Somarriba, E.
    • Deheuvels, O.
  • Source: Agriculture Ecosystems and Environment
  • Volume: 173
  • Year: 2013
  • Summary: The cocoa tree ( Theobroma cacao L.) is cultivated typically in agroforestry systems in close association with a rich list of tree species and other useful plants on the same plot. Cocoa based agroforestry systems are credited for stocking significant amounts of carbon and hence have the potential to mitigate climate change. Since cocoa yields decrease non-linearly with increasing shade, a need is to design optimal cocoa agroforestry systems with high yields and high carbon stocks. We estimated the carbon stocked in a network of 229 permanent sample plots in cacao-based agroforestry systems and natural forests in five Central American countries. Carbon stocks were fractioned by both system compartments (aboveground, roots, soil, litter, dead wood - fine and coarse, and total) and tree use/form (cocoa, timber, fruit, bananas, shade and ornamentals, and palms). Cocoa plantations were assigned to a five-class typology and tested for independence with growing region using contingency analysis. Most Central American cocoa plantations had mixed or productive shade canopies. Only 4% of cocoa plantations were full sun or rustic (cocoa under thinned natural forest). Cocoa tree density was low (548192 trees ha -1). Total carbon (soil+biomass+dead biomass) was 11747 Mg ha -1, with 51 Mg ha -1 in the soil and 49 Mg ha -1 (42% of total carbon) in aboveground biomass (cocoa and canopy trees). Cocoa trees accumulated 9 Mg C ha -1 (18% of carbon in aboveground biomass). Timber and fruit trees stored 65% of aboveground carbon. The annual rate of accumulation of carbon in aboveground biomass ranged between 1.3 and 2.6 Mg C ha -1 y -1. Trade-offs between carbon levels and yields were explored qualitatively using functional relationships documented in the scientific and technical literature, and expert knowledge. We argue that it is possible to design cocoa-based AFS with good yields (cocoa and shade canopy) and high carbon stock levels. The botanical composition of the shade canopy provides a large set of morphological and functional traits that can be used to optimize shade canopy design. Our results offer Central American cocoa producers a rigorous estimate of carbon stocks in their cocoa plantations. This knowledge may help them to certify and sell their cocoa, timber, fruits and other goods to niche markets with good prices. Our results will also assist governments and the private sector in (i) designing better legal, institutional and policy frameworks, local and national, promoting an agriculture with trees and (ii) contributing to the development of the national monitoring, reporting and verification systems required by the international community to access funding and payment for ecosystem services.