• Authors:
    • Saenjan, P.
    • Iwai, C. B.
    • Oo, A. N.
  • Source: LAND DEGRADATION & DEVELOPMENT
  • Volume: 26
  • Issue: 3
  • Year: 2015
  • Summary: The aim of this study was to investigate the effectiveness of compost and vermicompost as soil conditioners in alleviating salt-affected soils and increasing maize productivity. A greenhouse trial, consisting of seven soil amendment treatments in a completely randomized design with three replications, was carried out at Khon Kaen University, Thailand, during the rainy season of 2011. Plant height and total dry matter of maize increased in treatments with compost and vermicompost application when compared with the control (no fertilizer) in two types of soils (saline and nonsaline) during the growing season. Soil pH and electrical conductivity in saturation paste extracts were decreased by compost and vermicompost amendments with or without earthworms when compared with unamended treatments in the saline soil. Compost and vermicompost amendments improved cation exchange capacity, soil organic carbon, total nitrogen and extractable phosphorus in both soils. These amendments also increased exchangeable K+, Ca2+ and Mg2+ while decreasing exchangeable Na+ in the saline soil, which suggested that Ca2+ was exchanged for Na+, exchangeable Na+, then leached out, and soil salinity reduced as a result. Soil microbial activities including microbial C and N and basal soil respiration were improved by the application of compost and vermicompost amendments with or without earthworms when compared with the control in both soils. This experiment showed that the compost and vermicompost were effective in alleviating salinity and improving crop growth.
  • Authors:
    • Tran,T.
    • Da,G.
    • Moreno-Santander,M. A.
    • Velez-Hernandez,G. A.
    • Giraldo-Toro,A.
    • Piyachomkwan,K.
    • Sriroth,K.
    • Dufour,D.
  • Source: Resources, Conservation & Recycling
  • Volume: 100
  • Year: 2015
  • Summary: Energy use, water use and greenhouse gas (GHG) emissions were assessed for the transformation of cassava roots into starch by two small-scale (ST1, ST2: 1-2 t starch per day) and one large-scale (VLT: 100-200 t starch per day) technologies. The goal of the study was to identify hotspots of energy use and GHG emissions, as well as sustainable practices, with a view to uncover opportunities to improve the environmental performance of cassava starch production. VLT required 2527 MJ/t starch, mainly (77%) from biogas used to dry starch, but was the most efficient in terms of water use (10 m 3/t starch) due to the practice of water recycling between unit operations. ST1 and ST2 were similar in terms of electricity use (212 MJ/t starch), and were able to rely on solar energy to dry starch, due to the small volumes of production. In contrast, water use varied from 21 to 62 m 3/t starch due to differences in the design of the rasping and starch recovery (extraction) operations. GHG emissions were 149, 93 and 105 kg CO 2eq/t starch for VLT, ST1 and ST2 respectively. For ST1 and ST2, methane emissions from untreated wastewater were the main contribution to GHG emissions. For VLT, methane was captured to produce biogas and to dry starch, and the main contribution to GHG emissions was the use of non-renewable grid electricity. Biogas technology was adopted in the past 12 years in the case of VLT. Previously fuel oil was used instead of biogas, which resulted in GHG emissions of 539 kg CO 2eq/t starch. VLT used markedly more electricity than ST1 and ST2, which was necessary to ensure the high output and consistent starch quality. Strategies to reduce the impacts of cassava starch production could focus on (1) increasing the energy efficiency of the drying operation, in order to make more biogas available for other uses such as production of renewable electricity; (2) improving the design of some unit operations with regards to water and energy efficiency; and (3) promoting the transfer and adoption of water recycling practices.
  • Authors:
    • Polprasert, C.
    • Tangtham, N.
    • Chidthaisong, A.
    • Jaiarree, S.
    • Sarobol, E.
    • Tyler, S.
  • Source: Land Degradation and Development
  • Volume: 25
  • Issue: 2
  • Year: 2014
  • Summary: The effects of compost application on soil carbon sequestration potential and carbon budget of a tropical sandy soil was studied. Greenhouse gas emissions from soil surface and agricultural inputs (fertiliser and fossil fuel uses) were evaluated. The origin of soil organic carbon was identified by using stable carbon isotope. The CO2, CH4 and N2O emissions from soil were estimated in hill evergreen forest (NF) plot as reference, and in the corn cultivation plots with compost application rate at 30 Mg ha(-1) y(-1) (LC), and at 50 Mg ha(-1) y(-1) (HC). The total C emissions from soil surface were 8 center dot 54, 10 center dot 14 and 9 center dot 86 Mg C ha(-1) y(-1) for NF, HC and LC soils, respectively. Total N2O emissions from HC and LC plots (2 center dot 56 and 3 center dot 47 kg N2O ha(-1) y(-1)) were significantly higher than from the NF plot (1 center dot 47 kg N2O ha(-1) y(-1)). Total CO2 emissions from fuel uses of fertiliser, irrigation and machinery were about 10 per cent of total CO2 emissions. For soil carbon storage, since 1983, it has been increased significantly (12 Mg ha(-1)) under the application of 50 Mg ha(-1) y(-1) of compost but not with 30 Mg ha(-1) y(-1). The net C budget when balancing out carbon inputs and outputs from soil for NF, HC and LC soils were +3 center dot 24, -2 center dot 50 and +2 center dot 07 Mg C ha(-1) y(-1), respectively. Stable isotope of carbon (delta C-13 value) indicates that most of the increased soil carbon is derived from the compost inputs and/or corn biomass. Copyright (c) 2011 John Wiley & Sons, Ltd.
  • Authors:
    • Treloges, V.
    • Saenjan, P.
    • Rasche, F.
    • Vityakon, P.
    • Puttaso, A.
    • Cadisch, G.
  • Source: SOIL SCIENCE SOCIETY OF AMERICA JOURNAL
  • Volume: 77
  • Issue: 3
  • Year: 2013
  • Summary: The influence of residue quality on soil organic C (SOC) retention has been called into question. A field experiment in Northeast Thailand, in which contrasting quality organic residues were applied yearly for 13 yr, was used to determine quantities, locations, and stability of SOC in the soil matrix and identify residue quality parameters affecting SOC stabilization in a tropical sandy-textured soil. Total organic C (TOC) content was highest in intermediate- quality tamarind (Tamarindus indica L.) at 3.58 g kg-1 (intermediate N, lignin, and polyphenol contents), followed by groundnut (Arachis hypogaea L.) stover at 2.63 g kg-1 (high N), dipterocarp (Dipterocarpus tuberculatus Roxb.) at 2.63 g kg-1 (low N, high lignin and polyphenols), and rice (Oryza sativa L.) straw at 1.77 g kg-1 (high cellulose). Microaggregates (Mi) (0.053-0.25 mm) stored the highest C content (34-49% of TOC), with tamarind having the highest C content. Carbon in large macroaggregates (>2 mm), small macroaggregates (0.25-2 mm), and free organic matter (>0.053 mm) was significantly positively correlated with C, lignin, and polyphenols. Carbon in microaggregates and fine particles (<0.053 mm) was significantly negatively correlated with C/N ratio. Soil fraction C was negatively correlated with residue cellulose contents. Protected C lost through mineralization in Mi was lower in tamarind (7% Mi-C) followed by groundnut (9.5%), dipterocarp (17.7%), and rice straw (18.6%). It was significantly positively correlated with cellulose and C/N ratios but negatively correlated with N contents. Possible mechanisms of aggregate formation are based on microbial synthesis of both persistent (humic substances) and transient (polysaccharides) binding agents as influenced by residue quality. The results showed clearly that residue quality plays an important role in SOC accumulation in tropical sandy soils.
  • Authors:
    • Managanvi, K.
    • Erayya
    • Makanur, B
    • Jagdish, J.
  • Source: Environment and Ecology
  • Volume: 31
  • Issue: 2
  • Year: 2013
  • Summary: The evidence for climate change is now considered to be unequivocal, and trends in atmospheric carbon dioxide (CO 2), temperature and sealevel rise are tracking the upper limit of model scenarios elaborated in the Fourth Assessment (AR4) undertaken by the International Panel on Climate Change (IPCC). Agriculture directly contributes almost 14% of total Green House Gas (GHG) emissions and indirectly accounts for a further 7% incurred by the conversion of forests to agriculture (mostly conversion to rangeland in the Amazon), currently at the rate of 7.3 million ha/year. It focuses on specific aspects of agriculture and agricultural water management that contribute to greenhouse gas emissions and offer prospects for mitigation. In addition to the impacts of cycles of wetting and drying, the concentration of inorganic and organic fertilizer on land with some form of water management means that the practice of irrigation has scope to mitigate GHG emissions. Global atmospheric temperature is predicted to rise by approximately 4°C by 2080, consistent with a doubling of atmospheric CO 2 concentration. Increased atmospheric concentrations of CO 2 enhance photosynthetic efficiency and reduce rates of respiration, offsetting the loss of production potential due to temperature rise. Early hopes for substantial CO 2 mitigation of production losses due to global warming have been restrained. A second line of reasoning is that by the time CO 2 levels have doubled, temperatures will also have risen by 4°C, negating any benefit.
  • Authors:
    • Sajjakulnukit, B.
    • Jenjariyakosoln, S.
    • Garivait, S.
  • Source: International Journal of Environmental Science and Development
  • Volume: 4
  • Issue: 2
  • Year: 2013
  • Summary: This paper presents an approach to evaluate the net energy potential of sugarcane field residues in Thailand. It was estimated that around 13,595 ktons of sugarcane field residues was burned in the field annually in the country. Assuming 100% collection efficiency, this amount could be converted to 210.46 PJ through power generation. The quantity of greenhouse gases (GHGs) including CO 2, CH 4, and N 2O emitted from open burning of sugarcane residues was compared to that released from power production using life cycle analysis methodology for the estimation. It was found that the avoided GHG emissions obtained for power generation represent 11,836 ktons CO 2 equivalent, based on the country specific emission factor of electricity production using coal as fuel of 1.09 kg CO 2/kWh. Although this enormous potential for energy production in Thailand, sugarcane field residues availability is subject to seasonal variability, which limits its capacity to serve as fuel for power generation. The total avoided GHG emissions were therefore 11,836 ktons CO 2eq and 8,285 ktons CO 2eq annually for collection efficiency of 100% and 70%, respectively. Comparatively to the national CO 2 emissions from coal power generation of 34,532 ktons CO 2eq in 2011, the avoided GHG emissions would be about 34% and 24% for collection efficiency of 100% and 70%, respectively.
  • Authors:
    • Polprasert, C.
    • Patthanaissaranukool, W.
    • Englande, A.
  • Source: Applied Energy
  • Volume: 102
  • Year: 2013
  • Summary: This study aimed to evaluate energy and carbon equivalences (CE) associated with palm oil milling and to evaluate sustainability alternatives for energy consumption. Appropriate ways to reduce carbon emissions were also evaluated. A field survey was carried out to quantify the input and output of energy and materials following the conceptual framework of a carbon-balanced model (CBM), which exclude other non-CO2 greenhouse gases. Survey results indicate that the electrical energy consumption for daily mill start-up averaged 18.7 +/- 5.4 kWh/ton Fresh Fruit Bunches (FFBs). This energy is equivalent to 114.4 +/- 33.2 kWh/ton Crude Palm Oil (CPO) which was found to be offset by that generated in the mills using palm fiber as a solid fuel. Currently, organic residues contained in the wastewater are anaerobically converted to methane. The methane is used as fuel to generate electricity and sold to an outside grid network at a generation rate of 8.1 +/- 2.1 kWh/ton FFB. Based on the CBM approach, carbon emissions observed from the use of fossil energy in palm oil milling were very small; however, total carbon emission from oil palm plantation and palm oil milling were found to be 12.3 kg CE/ton FFB, resulting in the net carbon reduction in CPO production of 2.8 kg CE/ton FFB or 53.7 kg CE/ha-y. Overall, the sum of C-reduction was found 1.2 times greater than that of C-emission. This figure can be increased up to 5.5, if all biomass by-products are used as fuel to generate electricity only. The full potential for carbon reduction from palm oil milling is estimated at 0.94 kW of electric power for every hectare of plantation. This equates to a quantity of 68 kg CE reduced per ton of FFB. Thus, utilization of palm oil biomass can have a significantly high potential as a resource to be used for climate change mitigation by reducing carbon emissions. The findings of this work can be used as a template for policy makers to use in assessing and planning their energy programs. (c) 2012 Elsevier Ltd. All rights reserved.
  • Authors:
    • Salokhe, V. M.
    • Taewichit, C.
    • Soni, P.
  • Source: Agricultural Systems
  • Volume: 116
  • Year: 2013
  • Summary: Farm mechanization has been progressively increasing in Thailand for the past decades. Consumption and abuse of energy intensive inputs, machinery and agro-chemicals is increasingly propagated into agricultural production systems. Effects of energy intensive input utilization and farm technologies are directly associated especially with farm economic and atmospheric issues. This warrants the need of energy input-output analyses coupled with its environmental dimension. This paper presents the energy input-output analyses of different agricultural activities and fresh pond-culture (polyculture), for which data were collected from 46 rainfed integrated agricultural production systems (IAPSs) of 281 farm plots surveyed. Total energy consumption including non-renewable energy input (NREI), direct and indirect energy input, and system efficiency are calculated and compared for different crops. Resource-wise energy input utilization and energy consumed by farm operations are also discussed for different crops. Further, this study simultaneously relates energy consumption in agricultural production systems associated with their corresponding greenhouse gases (GHGs) emission - presented in terms of total carbon dioxide equivalent (CO(2)e). Results reveal noticeable variations in energy consumption and CO(2)e emissions from various agricultural production activities. The study reveals that the maximum energy consumer is cassava (32.4 GJ ha(-1)). Major energy input consumption for all productions are indicated by fossil fuel (diesel oil) as fresh pond-culture depended on fish feed. Transplanted rice provides the highest CO(2)e emission (1112 kg CO(2)e ha(-1)) among crops, in which more than 50% is contributed by methane (CH4).
  • Authors:
    • Chidthaisong, A.
    • Lu, Y.
    • Yuan, Q.
    • Klose, M.
    • Conrad, R.
  • Source: Soil Biology and Biochemistry
  • Volume: 49
  • Issue: June
  • Year: 2012
  • Summary: Straw amendment is a common practice for improving the fertility of rice field soils, but it also enhances production of the greenhouse gas methane. To quantify carbon flux partitioning and priming effects due to straw amendment, we measured delta C-13 in CH4 and CH4 precursors produced in anoxic slurries of soil from Italy, China and Thailand after addition of straw from either rice (C3 plant) or maize plants (C4 plant), which have different delta C-13 signatures. The delta C-13 values of the CH4, acetate and CO2 produced were similar when expressed as the difference to the delta C-13 value of the straw applied. These results indicated that the C-13-isotopic fractionation involved in methanogenic decomposition was similar for rice straw and maize straw. However, measurement of CH4 produced in soil without or with straw showed that isotopic fractionation during methanogenic degradation of straw was smaller than during degradation of soil organic matter. Isotopic fractionation during hydrogenotrophic methanogenesis, measured in the presence of methyl fluoride, with straw was also smaller than with soil organic matter. The results show that C-13-isotopic analysis after application of rice straw and maize straw is a convenient approach for quantifying carbon flux partitioning during methanogenic degradation of straw and soil organic matter. In our experiments, straw degradation accounted for most of the CH4 production and caused a negative priming effect on the methanogenic degradation of soil organic matter. (c) 2012 Elsevier Ltd. All rights reserved.
  • Authors:
    • Chernchom, P.
    • Wetayaprasit, P.
    • Somboonsuke, B.
    • Pacheerat, K.
  • Source: Kasetsart Journal, Social Sciences
  • Volume: 32
  • Issue: 2
  • Year: 2011
  • Summary: The rubber agroforestry system is an alternative agriculture practice for rubber smallholders to enhance the ecological integrity and crop diversity. The data collection for the study of diversification of smallholding rubber agroforestry system (SRAS) included 300 rubber farms of 21 systems in the south, east, and northeast of Thailand. The project results revealed that there are a multitude of 21 rubber farming systems in Thailand. These systems can be classified into three main types: (1) the intercropping rubber-food crop system, growing short-lived plants, for example, pineapple, chili, banana, rice, sweet potato, long bean and corn, for a rubber period, no longer than 36 months; (2) the rubber-fruit crop system, growing multicrop within the rubber area during the rubber productive period. The most common fruit crops that have been grown in Thailand are guava, gnetum, long kong, salacca, mangosteen, durian, and levistona, etc., and (3) the rubber-timber species system, normally yielding higher income to rubber smallholders since the sales of both rubber and wood products are at the same time and this is coupled with the presently high value of wood. The important timber varieties in the rubber area are neem and teak. As for profitability of Smallholding Rubber Agro forestry System (SRAS), it was noted that pineapple, chili, salacca, and gnetum are highly profitable. However, in the rubber-pineapple system which yields the highest income, the cost of investment is the highest too, when compared to the rubber-gnetum system which requires minimal input and low cost of production and management. The main conditions for decision-making in the rubber intercropping system are as follows: (1) farm household labor requirement, (2) knowledge and experience, (3) extension and policy implication, (4) marketing opportunity, (5) consistent capability of local communities, and (6) land topography and sustainability. For SRAS development strategy in the southern Thailand, improvement should be made on pricing and marketing of agroforestry products, appropriate technology for higher productivity, greater farm efficiency and risk reduction at farm level, and more synchronized co-ordination among stakeholder agencies at the regional level.