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An alternative to agricultural residues management is to convert them to biochar because this organic amendment can act as a superior soil conditioner that improves soil productivity. Nevertheless, the low density of biochar poses a challenge in the handling biochar. Tableting of biochar can mitigate the aforementioned problems associated with biochar. The objectives of this study were to determine the physico-chemical properties, nutrient release and soil ammonia volatilization of biochar tablets with and without embedded fertilizers. The different rates of biochar tablets with and without embedded fertilizers impact on selected soil chemical characteristics and nutrient use efficiency (NUE) of sweet corn (test crop) were also determined. Next planting cycle was conducted to determine the effects of combination biochar and fertilizers with and without tableting on selected soil chemical characteristics and NUE of sweet corn (test crop). The composition of biochar mixture was 50% charred rice husk, 30% charred rice straw, and 20% charred rubber twigs. The NPK fertilizers used for this study were ammonium sulfate (AS), triple superphosphate (TSP), and muriate of potash (MOP). The biochar tablet (BT) was produced by blending a biochar mixture with starch followed by tableting using a single punch tablet press whereas the fertilizer embedded biochar tablet (BF) was prepared using the same procedure except that NPK fertilizers were added during blending. Similarly, a combination of biochar and NPK without tableting (Biochar + NPK) was prepared. The ratio of biochar to fertilizers mixture used for the BF and Biochar + NPK production was 2:1. Standard procedures were used to characterize BT, BF, Biochar + NPK, and NPK. The nutrient release of the biochar and fertilizers with- and without- tablets were determined using the water incubation over 30 days. The daily loss ammonia was measured using a closed dynamic air flow system model for 10 days. A pot experiment with six f

Blending fertilizer with biochar followed by densification to make it into a tablet can enhance the adsorption of fertilizer on the biochar surface and reduce the nutrient loss during handling. However, the nutrient release and ammonia volatilization from biochar-blended fertilizer with and without densification are not well understood. The objectives of this study were to determine the nutrient release and ammonia volatilization from an acid soil applied with biocharblended NPK fertilizer with and without densification. The nutrient release of biochar-blended NPK was determined using water incubation for 30 days, whereas daily loss of ammonia was measured using a closed dynamic air flow system for 10 days. The densified biochar-blended NPK caused stronger physical binding of the nutrients within the tablet in addition to stronger chemical bondings between the nutrients with the biochar’s functional groups. As a result, nutrient release in the water incubation from the biochar-blended NPK fertilizer tablet was slower. However, blending the biochar with the NPK fertilizer increased soil ammonia volatilization relative to the NPK fertilizer alone. This demonstrates that the biochar-blended fertilizer tablet has the potential to serve as a slow release fertilizer for crop cultivation.

In 2008, the very extensive tropical peats were estimated to be about 182 million ha spanning South America, Asia and Africa. About 20.3% (36.9 million ha) of this area exist in Asia. Peats are classified based on their degree of decomposition, namely Fibrists, Hemists, Saprists and Folists. This makes them different in characteristics. The activities of microorganisms vary in different types of peat due to, for example, the sapric layer of well humified peat can provide water and food to microorganisms during heat stress. In another scenario, deeper peat is older and typically has lower levels of labile carbon to provide substrate for microbes compared to surface peat. A complete understanding of the microbial communities in different layers of peat is essential as microorganisms play major roles in peat decomposition and are important to ecosystem processes. These peats are a very important global carbon (C) store or reserve and could severely impact climate change if not managed well. Peatlands can store as much as 40 to 90 Gt C. Mis-management of peats could severely impact the environment particularly the emission of carbon into the atmosphere. For instance, clearing of peatlands using fire has been reported to release an estimated 88 t C ha−1 to the atmosphere. There are several factors which influence the environmental consequences of tropical peat especially in relation to climate change. The main influences are: (i) changes in temperature, (ii) changes in precipitation or rainfall, (iii) changes in atmospheric composition, and (iv) fire and haze. This paper is a brief review on these four influences in relation to climate change. It is apparent from the brief review that there is a need for continued short and long-term research to better understand tropical peats and how they affect our climate. This will hopefully provide the basis for predicting better what could happen under various scenarios.

In this study, the characteristics and heating values of raw pellet (RP) and charred pellet (CP) made from rice residues-rubber tree twigs mixture were compared. The carbonization process to produce the charred plant residues was conducted in a locally fabricated stainless steel kiln. Both the RP and CP were evaluated for their heating values, pellet durability, carbon and inorganic ash content. The CP had higher heating value and carbon content than the RP. However, the ash content of CP was higher. The results indicate that the pellet made from the charred rice residues-rubber tree twigs mixture could be a suitable source of renewable fuel.

Densification of biochar can reduce transportation and handling costs, as well as significantly decrease loss of biochar during soil application. Although the nutrient-rich biochar tablets may be a potential cost-effective slow-release fertilizer in soil, there is a lack of information on characterization of mixtures of rubber tree twigs and rice residues tablets with embedded NPK fertilizer. Objective of this work was to determine the physical and chemical properties of biochar tablets with and without embedded fertilizer. Biochar tablets were produced by blending of charred rice husk, rice straw, rubber tree twigs, and starch and followed by tableting. Their production with embedded fertilizer was similar to production process of tablets without it, except adding the NPK fertilizer to blending phase prior to tableting. Fourier-transform infrared spectra analysis indicates was utilized for determination of presence of ammonium and phosphorus substances in the biochar tablets with embedded fertilizer (BFs). The NPK fertilizer significantly increased tablet density and total contents of nitrogen, phosphorus, potassium, calcium and magnesium. The presence of higher amount of nutrients in BFs suggests that it could release nutrients for plant use.

This study was undertaken to compare the chemical characteristics of pineapple leave residues (PLRs) char generated by controlled combustion and by open burning. The properties of char generated by control combustion (CC) and open burning (OB) varied, due to differences in the production process. The total N, K and surface area of the char generated by CC were significantly higher than the OB. The results indicate that the CC process was better to be applied as a soil amendment than was the OB process.

The study was undertaken to determine the decomposition of pineapple leaf residue (PLR) char produced by controlled combustion in the laboratory (CL) and by field burning (FB) with and without added fertilizer in tropical peat over 12 months. Decompositions of both chars with and without added fertilizer fit the three-parameter single exponential decay model. Fertilizer treatment significantly reduced the weight and lignin remainings in the CL and CF biochars after 12 months. Total C remaining in the biochar showed an increase in this order: CF + fertilizer < CF < CL + fertilizer < CL. The aliphatic functional groups of both chars transformed to aromatic groups 12 months after application to the peat. The pot study indicates that the total C, recalcitrant fractions and lignin content of char made by CL were higher than the char made by FB. The results suggest that to produce biochar for carbon sequestration purposes, the PLR should be carbonized in a CL process rather than by FB.

Oxidation of peat in combination with biomass burning on dry surface peat could result in substantial carbon emissions to the atmosphere contributing to climate change processes. Conversion of biomass into biochar is able to reduce CO2 levels in the atmosphere by sustainably sequestering C. Field burning of pineapple leaf residues (PLR) on peat is a traditional practice to prepare land for cultivation. However, during the open burning not all of the PLR are converted into biochar but ash will also be produced. Biochar produced under controlled combustion is hypothesized to have better yield and quality, thereby better in sequestering C than the biochar produced from the open burning. The study was undertaken to compare the chemical properties and yields of PLR biochar produced by field burning (CF) with that produced by a partial combustion of air-dried PLR in a furnace (CL). Futhermore, the biochar decomposition with and without added fertilizer in the peat were determined. Biochar produced by the CF and the peat samples were collected from Peninsula Plantation, Johor, Malaysia. The CL biochar was produced by partially combusting the PLR at 340°C for 3 hours in a furnace. Standard procedures were used to determine the chemical properties of biochars produced by CL and CF. The refractory nature of biochar samples were determined by analyzing the lignin content and C/N ratio. The chemical functional groups of PLR and biochar samples were identified using Fourier Transform Infrared Spectrocopy (FTIR). The decomposition of biochars with and without added fertilizer on the tropical peat over 12 months were determined using the litterbag method. Total C (42.19%), lignin content (55.45%) and yield (5.63%) from CF was found to be significantly lower than CL. Higher total C (53.30%), lignin content (63.34%), and yield (33.71%) from CL as well as the presence of aromatic compounds in the FTIR spectra of the CL biochar suggest that the CL process was better in sequestering C

This study was undertaken to compare the chemical properties and yields of pineapple leaf residue (PLR) char produced by field burning (CF) with that produced by a partial combustion of air-dried PLR at 340 °C for 3 h in a furnace (CL). Higher total C, lignin content, and yield from CL as well as the presence of aromatic compounds in the Fourier Transform Infrared spectra of the char produced from CL suggest that the CL process was better in sequestering C than was the CF process. Although the C/N ratio of char produced from CL was low indicating a high N content of the char, the C in the char produced from CL was dominated by lignin suggesting that the decomposition of char produced from CL would be slow. To sequester C by char application, the PLR should be combusted in a controlled process rather than by burning in the field.

Problem Statement: Tropical rainforests cover about 19.37 million ha (60%) of Malaysia's total area and about 8.71 million ha can be found in Sarawak, Malaysia. Excessive logging, mining and shifting cultivation contribute to deforestation in Sarawak. The objectives of this study were to: (i) Quantify soil Organic Matter (SOM), Soil Organic Carbon (SOC) and Humic Acids (HA) in rehabilitated and secondary forest soils and (ii) Compare SOM, SOC and HA sequestrations of both forests. Approach: Soil samples were collected from a 16 year old rehabilitated forest and a secondary forest at Universiti Putra Malaysia, Bintulu Campus. Fifteen samples were taken at random with a soil auger at 0-20 cm and 20-40 cm depths. The bulk densities at these depths were determined by the coring method. The bulk density method was used to quantify the total C (TC), Total Organic Carbon (TOC), Organic Matter (OM), Humic Acids (HA) and total N at the stated sampling depths. Results: Regardless of forest soil type and depth, the amount of SOM of the two forests was similar. Except for 20-40 cm of the secondary forest soil whereby the quantity of total C sequestered was significantly lower than that of the rehabilitated forest soil, C sequestration was similar irrespective of forest type and depth. Nevertheless, stable C (organic carbon) sequestered in HA was generally higher in the rehabilitated forest soil compared with the secondary forest soil. This was attributed to higher yield of HA in the rehabilitated forest soil partly due to better humification at 20-40 cm in the rehabilitated forest soil. Conclusion: Hence, the findings suggest that organic C in HA realistically reflects C sequestration in the soils of the two forests investigated. © 2009 Science Publications.

Problem Statement: Tropical rainforests cover about 19.37 million ha (60%) of Malaysia’s total area and about 8.71 million ha can be found in Sarawak, Malaysia. Excessive logging, mining and shifting cultivation contribute to deforestation in Sarawak. The objectives of this study were to: (i) Quantify soil Organic Matter (SOM), Soil Organic Carbon (SOC) and Humic Acids (HA) in rehabilitated and secondary forest soils and (ii) Compare SOM, SOC and HA sequestrations of both forests. Approach: Soil samples were collected from a 16 year old rehabilitated forest and a secondary forest at Universiti Putra Malaysia, Bintulu Campus. Fifteen samples were taken at random with a soil auger at 0-20 cm and 20-40 cm depths. The bulk densities at these depths were determined by the coring method. The bulk density method was used to quantify the total C (TC), Total Organic Carbon (TOC), Organic Matter (OM), Humic Acids (HA) and total N at the stated sampling depths. Results: Regardless of forest soil type and depth, the amount of SOM of the two forests was similar. Except for 20-40 cm of the secondary forest soil whereby the quantity of total C sequestered was significantly lower than that of the rehabilitated forest soil, C sequestration was similar irrespective of forest type and depth. Nevertheless, stable C (organic carbon) sequestered in HA was generally higher in the rehabilitated forest soil compared with the secondary forest soil. This was attributed to higher yield of HA in the rehabilitated forest soil partly due to better humification at 20-40 cm in the rehabilitated forest soil. Conclusion: Hence, the findings suggest that organic C in HA realistically reflects C sequestration in the soils of the two forests investigated.