Sifat Fisik, Kimia dan FTIR Spektrofotometri Gambut Hidrofobik Kalimantan Tengah

Nature on Soil Phisical, Chemical and Ftir Spectrophotometry of Hydrophobic Peat From Central Kalimantan (S.N.H. Utami, A. Maas, B. Radjagukguk, and B.H. Purwanto): Peat soils naturally have hydrophilic or water-loving character with highly capable of exchanging the cations and cycling the nutrients from the vegetations. This water-loving character is altered to water-repellent character in hydrophobic peat soils. This research was aimed to observe deeply the functional bunch carrier of hydrophobic and hydrophilic peat soils as shown by FTIR spectra in relation with inherent chemical and physical properties of the soils. Five peat soils consisted of two native and artificial hydrophobic peat soils and one sample of hydrophilic peat soils were studied. Artificial hydrophobic peat soils were yielded by oven-drying the native hydrophobic peat soils at 50 oC for 10 hours. FTIR spectra can distinguish the functional bunch carrier of hydrophobic and hydrophilic peat soils. FTIR spectra of hydrophobic peat soils showed degradation of hydrophilic bunch carrier (¾OH and ¾COOH) and increase of the hydrophobic bunch carrier (tying aromatic from esther and ether). Chemical analysis  of the hydrophobic peat soils also indicated the decrease of ¾OH and ¾COOH content, decrease of CEC , soil total acidity and soil moisture content

Rewetting offers rapid climate benefits for tropical and agricultural peatlands but not for forestry‐drained peatlands

Peat soils drained for agriculture and forestry are important sources of carbon dioxide and nitrous oxide. Rewetting effectively reduces these emissions. However, rewetting also increases methane emissions from the soil and, on forestry-drained peatlands, decreases the carbon storage of trees. To analyze the effect of peatland rewetting on the climate, we built radiative forcing scenarios for tropical peat soils, temperate and boreal agricultural peat soils, and temperate and boreal forestry-drained peat soils. The effect of tree and wood product carbon storage in boreal forestry-drained peatlands was also estimated as a case study for Finland. Rewetting of tropical peat soils resulted in immediate cooling. In temperate and boreal agricultural peat soils, the warming effect of methane emissions offsets a major part of the cooling for the first decades after rewetting. In temperate and boreal forestry-drained peat soils, the effect of rewetting was mostly warming for the first decades. In addition, the decrease in tree and wood product carbon storage further delayed the onset of the cooling effect for decades. Global rewetting resulted in increasing climate cooling, reaching -70 mW (m(2)Earth)(-1)in 100 years. Tropical peat soils (9.6 million ha) accounted for approximately two thirds and temperate and boreal agricultural peat soils (13.0 million ha) for one third of the cooling. Forestry-drained peat soils (10.6 million ha) had a negligible effect. We conclude that peatland rewetting is beneficial and important for mitigating climate change, but abandoning tree stands may instead be the best option concerning forestry-drained peatlands.Peer reviewe

Sifat Kimia Tanah Dan Pertumbuhan Tanaman Karet (Havea Brasiliensis Muell. Arg) Pada Tanah Gambut Yang Ditumbuhi Dan Tidak Ditumbuhi Mucuna Bracteata

One effort to improve the chemical properties of peat soils and the growth of rubber trees is by planting a legume cover crop Mucuna bracteata. The research aims to determine the chemical properties of the soil and the growth of rubber trees in peat soils without overgrown Mucuna bracteata with peat soils ex overgrown Mucuna bracteata and peat soil that overgrown Mucuna bracteata. The research was conducted in January – March 2016 in peat land at social plantation areal of PT. RAPP Teluk Meranti. The research was conducted by survey method where the determination of location specified by Stratified Random Sampling method and the determination of sample point specified by Simple Random Sampling method. The results showed that peat soil which is overground Mucuna bracteata has a pH value, C-organic, N-total, P-total, KTK, KB and the growth of rubber trees better than peat soils ex overgrown Mucuna bracteata and peat soils withouth overgrown Mucuna bracteata

Solubility of Rock Phosphate and SP-36 in Peat Soils Amended with Mineral Soil

Rock phosphates application on peat soil has a good prospect because of its high solubility in acid condition. However, the study of the solubility of rock phosphate in peat soils is still limited. This study aimed to quantify the solubility of rock phosphate and the effects of some sources of rock phosphates and SP-36 in the peat soils, taken from South Sumatera amended with mineral soil. The study was conducted in the laboratory ofIndonesian Soil Research Institute, in Bogor. The study consisted of two activities: 1) study on the solubility of some rock phosphates (Marocco, Christmas, and Ciamis) in peat soils. For this study a 100 g of oven dried (105oC) peat soil for each treatment was used for this study. The treatments were eleven levels of P i.e. 0, 10, 20, 30, 40, 50, 60, 75, 100, 125, and 150 ppm P applied to dried peat soils. The treated peat soils werethen incubated for 2 weeks before analyses of soluble P was conducted. The molybdat blue method was used to analyze the samples at 2, 4, 8, and 12 weeks after the incubation. 2) The second study i.e. the application of some rock phosphates or SP-36 on the peat soils amended with mineral soils, four levels of P (25, 50, 74, and 100% of P sorption) plus partial and complete control treatments have been replicated twice. Two hundred grams of oven dried peat soils (105oC) amended with mineral soils at 7,5% maximum Fe sorption, incubated for four weeks, and then soluble P was analyzed using molybdat blue at 1, 2, 4, 6, 8, 10, and 12 weeks after incubation. The results showed that the order of rock phosphates solubility in peat soils was Marocco> Ciamis>Christmas. The solubility of P in peat soils amended with mineral soil and rock phosphates gave similarresults as rock phosphate was in the order of SP-36>Marocco>Ciamis> Christmas. Soluble P increased up to 8 weeks of incubation, and then decreased. The effect of soil mineral ameliorant and some rock phosphates application of soluble P at 12 weeks after the incubation around 15.7-34.2 ppm P. Rock phosphates that has high reactivity gave a high Psolubility on peat soils so it that can be used as P sources in the peat soil

The influence of above-ground herbivory on the response of arctic soil methanotrophs to increasing ch4 concentrations and temperatures

Rising temperatures in the Arctic affect soil microorganisms, herbivores, and peatland vegetation, thus directly and indirectly influencing microbial CH4 production. It is not currently known how methanotrophs in Arctic peat respond to combined changes in temperature, CH4 concentration, and vegetation. We studied methanotroph responses to temperature and CH4 concentration in peat exposed to herbivory and protected by exclosures. The methanotroph activity was assessed by CH4 oxidation rate measurements using peat soil microcosms and a pure culture of Methylobacter tundripaludum SV96, qPCR, and sequencing of pmoA transcripts. Elevated CH4 concentrations led to higher CH4 oxidation rates both in grazed and exclosed peat soils, but the strongest response was observed in grazed peat soils. Furthermore, the relative transcriptional activities of different methanotroph community members were affected by the CH4 concentrations. While transcriptional responses to low CH4 concentrations were more prevalent in grazed peat soils, responses to high CH4 concentrations were more prevalent in exclosed peat soils. We observed no significant methanotroph responses to increasing temperatures. We conclude that methanotroph communities in these peat soils respond to changes in the CH4 concentration depending on their previous exposure to grazing. This “conditioning” influences which strains will thrive and, therefore, determines the function of the methanotroph community

Greenhouse gas emissions from compacted peat soil

Cultivated peat soils are a main driver for CO2 and N2O emissions, while the gas fluxes are dependent on intrinsic soil properties and land use. Sand addition into peat soils might reduce greenhouse gas (GHG) emissions and enhance soil strength, and thus the ability to tolerate soil compaction. Soil compaction due to vehicular traffic leads to a decrease in aeration and changes in water flow, which might alter microbial activity and gas flow. The goal of this thesis was to investigate how soil compaction with different stress levels and sand addition affect soil physical properties and GHG emissions of peat soils. Incubator measurements three days before and after compaction were used to analyze the effect of soil compaction, which was conducted in a uniaxial compression machine. Furthermore, a new method was developed to observe the dynamics of gas fluxes during compaction. Field measurements complemented the laboratory study to determine the effect of sand addition. The compressive behaviour of peat soils was examined using the compression (Cc) and recompression index (Cs) which are measures for soil compressibility and rebound after stress release. This study shows reduction of CO2 emissions after compaction. However, this effect might be due to the high initial water-filled pore space and at lower water contents, compaction might have the opposite effect on GHG emissions. Higher mechanical loading had an effect on CO2 fluxes, while the trend was unclear and seems to be dependent on water content. Methane fluxes were below the detection limit and compaction might lead to hot moments in N2O emission. Sand addition reduced CO2 emissions and influenced the compressive behaviour of peat soils by reducing soil compressibility but also rebound. Linear relationships between soil mechanical properties and initial void ratio were found, indicating the high dependency of mechanical behaviour on intrinsic soil properties. In conclusion, sand addition might be a good agricultural management practise for cultivated peat soils, while the impact of soil compaction on GHG emissions under different moisture regimes has to be further assessed. This pilot study, emphasizes a need of further research to improve understanding the influencing factors of vehicular traffic as well as sand addition on GHG emissions and soil mechanical properties of cultivated peat soils

Impact of Sugarcane Bagasse Ash (SCBA) and Cement to the Strength Improvement of Hemic Peat

Peat soils are derived from organic deposition consisting of dead trees. Peat soils have low shear strength and cannot afford large loads. Various treatment methods are used to stabilize peat soils and most of them use cement as a main binder to increase the strength of peat soils. However, the use of large quantities of cement is not environment friendly due to the release of carbon dioxide (CO2) and wastage of energy consumption by the cement production industry. Therefore, the introduction of SCBA as a substitution binder for some cement dosage is good as well as reducing the degradation of dumping waste which is increasingly uncontrollable. The objective of this study is to identify the basic and physical properties of peat soil from Pontian, Johor. In addition, this study was also conducted to identify the impact of SCBA on peat soil stabilization with cement. There are 5 different mixtures for cement and SCBA which are C100, C95S5, C90S10, C85S15 and C80S20 used in this study. Sample C95S5 with mixtures 95% cement and 5% SCBA were the optimum samples for this study based on unconfined compression strength (UCS) tests. The C95S5 sample successfully achieved the maximum strength of the whole sample with a strength of 190 kN/m2, 209 kN/m2, and 219 kN/m2 recorded for wet curing periods of 7,14 and 28 days. Therefore, the use of SCBA materials in the stabilization of peat soils with cement and calcium chloride (CaCl2) is seen to have a positive effect in increasing the shear strength of Hemic peat soil samples

Toleransi Beberapa Varietas Padi pada Sawah Gambut Berkorelasi dengan Kandungan Asam Fenolat

One of the causes of the low productivity of rice grown on peat soils was the high levels of of toxic phenolic compounds in the soil. Development of tolerant rice varieties is one of strategies to grow rice on peat soils. The aims of this research were to select rice varieties tolerant to peat soils and to study the correlation between the plant phenolic acid content with plant tolerance to peat soil. This research was conducted at the Seed Farm Centre Lubuk Minturun, Padang from February to July 2009. The research consisted of two experiments i.e. in peat soil and in mineral soil. The experiments used a completely randomized design using 21 varieties of rice as treatments which were replicated four times. The results showed that there were nine rice varieties categorized as tolerant to peat soil. These tolerant varieties showed higher stress tolerance index (STI), demonstrated by a high level of phenolic acids (coumaric, syringic, and ferulic) in the plant tissues. The STI value had positive correlation with the content of plant phenolic acids, thus the level of plant phenolic acids can be used as an indicator to determine tolerant rice varieties in peat soils. Keywords: peat soil, phenolic acids, tolerant rice, ST