31. Greenhouse gas emissions from peat soils cultivated to rice field, oil palm and vegetable.

• Authors:
  • Inubushi, K.
  • Bakar, R.
  • Affandi, D.
  • Hadi, A.
• Source: Jurnal Tanah Tropika (Journal of Tropical Soils)
• Volume: 17
• Issue: 2
• Year: 2012
• Summary: Presently, about 20% of oil palm ( Elaeis guineensis Jacq) fields in Indonesia are on peat soil, in addition to that other area of peat soil has been conventionally used for rice field and vegetables. To elucidate the global warming potentials of peat soils cultivated to oil palm, vegetable or rice field, field experiment has been carried out in South Kalimantan. Air samples were taken from rice field, oil palm and vegetable fields in weekly basis for six month period and analyzed for concentrations of N 2O, CH 4 and CO 2. The global warming potentials (GWP) of the three gases were calculated by multiplying the emission of each gas with their respective mole warming potential. This step was followed by the addition of the three gases' GWP to have the total GWP. The results showed that the emissions of greenhouse gases from peat soils changed seasonally and varied with the crops cultivated. Oil palm has resulted the highest GWP, mostly contributed by N 2O. There was no statistical different in total GWP of paddy and vegetable fields. The annual N 2O emission from oil palm field was 4,582 g N ha -1 yr -1. Water, nutrients and organic matter managements are among the potential techniques to minimize gas emissions from oil palm field which need field trials.

32. The greenhouse gas balance of the oil palm industry in Colombia: a preliminary analysis. I. Carbon sequestration and carbon offsets.

• Authors:
  • Ruiz R., R.
  • Henson, I.
  • Romero, H.
• Source: Agronomia Colombiana
• Volume: 30
• Issue: 3
• Year: 2012
• Summary: Colombia is currently the world's fifth largest producer of palm oil and the largest producer in South and Central America. It has substantial areas of land that could be used for additional oil palm production and there is considerable scope for increasing yields of existing planted areas. Much of the vegetation on land suitable for conversion to oil palm has a low biomass, and so establishing oil palm plantations on such land should lead to an increase in carbon stock, thereby counteracting greenhouse gas (GHG) emissions responsible for global warming. The first part of this study examines changes in carbon stock in Colombia resulting from expansion of oil palm cultivation together with factors (offsets) that act to minimize carbon emissions. The results are subsequently used to construct a net GHG balance.

33. The greenhouse gas balance of the oil palm industry in Colombia: a preliminary analysis. II. Greenhouse gas emissions and the carbon budget.

• Authors:
  • Romero, H.
  • Ruiz R., R.
  • Henson, I.
• Source: Agronomia Colombiana
• Volume: 30
• Issue: 3
• Year: 2012
• Summary: In the preceding paper we examined carbon sequestration in oil palm plantations and in mill products and by-products as part of a study of the greenhouse gas balance of palm oil production in Colombia, showing how this has changed over time. Here, we look at the opposing processes of greenhouse gas (GHG) emission and calculate the resulting net carbon budget for the industry. The main emission sources, in decreasing order of magnitude, assessed using "default" or "most probable" options, were found to be land use change (40.9% of total), mill methane production (21.4%), direct use of fossil fuel (18.5%), indirect use of fossil fuel (11.9%) and nitrous oxide production (7.3%). The total (gross) emissions, expressed in carbon equivalents (Ceq.), were less than the amount of sequestered carbon, resulting in a positive net Ceq. balance. All oil palm growing regions showed a net gain with the exception of the western zone, where emissions due to land-use change were judged to be substantial. Of the 11 alternative scenarios tested, only three resulted in Ceq. balances lower than the default and only two gave a negative balance.

34. Impacts of organic amendments on carbon stocks of an agricultural soil - Comparison of model-simulations to measurements

• Authors:
  • Tuomi, M.
  • Vanhala, P.
  • Heikkinen, J.
  • Gardenas, A. I.
  • Karhu, K.
  • Liski, J.
• Source: Geoderma
• Volume: 189-190
• Year: 2012
• Summary: Organic amendments such as straw, green manure or farmyard manure are used to mitigate the soil carbon (C) losses from cultivated soils. We investigated the role of various organic amendments with different C quality for development of soil C stocks, by simulating the Ultuna long-term soil organic matter experiment in Sweden with the Yasso07 model. The aim was to evaluate the performance of the Yasso07 soil carbon model in predicting changes in soil C stocks by comparing modeled C stocks to measurements between years 1956-1991. Uncertainty bounds were calculated from the estimated uncertainty in the C inputs and model parameters. The model performance was assessed in terms of regression coefficient (R-2), root mean square error (RMSE) and model efficiency (ME). The model could very accurately predict the decrease in soil C stock in bare fallow, and in treatments receiving crop litter inputs and N fertilization. Yasso07 could also predict the increase in C stocks due to different organic matter applications, based on the varying quantity and quality of these C inputs. These results support the use of the model for testing the long-term effects of different agricultural measures aiming to mitigate soil C losses.

35. Influence of soil aggregate size on greenhouse gas emission and uptake rate from tropical peat soil in forest and different oil palm development years

• Authors:
  • Melling, L.
  • Kimura, S. D.
  • Goh, K. J.
• Source: Geoderma
• Volume: 185-186
• Year: 2012
• Summary: The influence of oil palm development on tropical peat soil decomposition rate was investigated by an incubation experiment. Soil samples from soil surface and around underground water table were taken from forest site, and oil palm site at 1st and 9th year after development. The soil samples were sieved into 0-2 mm, 2-8 mm and 8-20 mm and analyzed for carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes. The development of oil palm did not change the CO2 emissions and showed inconsistent influence on CH4 flux according to aggregate size, while significantly higher N2O emissions were found for aggregates 0-2 mm at high moisture of oil palm plantation soils compared with the original forest Nitrous oxide fluxes showed significant positive correlation with the CO2 flux, which indicated that soil organic matter decomposition was closely related to the N2O production. On the other hand, CH4 flux showed clear emission for aggregates bigger than 2 mm, while aggregates size 0-2 mm showed consistent CH4 uptake. These results showed that investigation of greenhouse gas emissions in tropical peat soil must take into account the aggregate characteristics of the soil, which are inhomogeneous and mixed with fresh organic matter.