Degraded peatlands can be detected laboratory analysis and field appearance. Peatlands degradation is characterized by a very reduced water holding capacity which is caused by peat fire or over drain. The capacity of peat to hold water is closely related to their functional groups. Analysis using Fourier Tansform Infrared (FTIR) Spectrocopy enable to determine the functional groups of peat. The research was aimed to study peatland degradation based on functional group changes through FTIR analysis. The samples of peat soil were taken from burned peatland, agricultural peat land and natural peat in Kalampangan, Central Kalimantan. The hydrophobic properties of the functional group are indicated as lignin, carboxylic or phenolic groups, fat, wax or lipids, while the hydrophilic functional group is indicated as protein and cellulose. Degraded peat have the hydrophobic group of 56.20%, while in natural peatlands was around 29%. Hydrophilic functional group on burned peatlands was 34.5-43%, natural peatland was 60-70% and agricultural peatland was 66%. Functional group analysis using FTIR can be used to detect the level of peatland degradation, through a significant increase in hydrophobic groups

The objective of this research was to investigate the effect of application of organic matter from rice straw (RS) on phosphate and Fe2+ solubility in the acid sulphate soils. The research was conducted in the glass house consisting of the three treatment factors using the completely randomized design with three replication. The first factor was soil condition : continuous application of RS and without application of RS during the last 5 years. The second factor was fresh application of RS ; with application and without application, whereas the third factor was phosphate application consisting 3 rates of SP - 36 fertilizers (0.5; 1,0 and 1.5 of application dossage). The result showed the three factors interaction had a significant influence on soil pH at 2 weeks after planting, whilst interaction between RS application and soil condition had a significant influence on soil pH, available phosphate at 4, 6 and 8 weeks after planting. The interaction between RS application and phosphate fertilizers rate had a significant influence on soil pH 4 weeks after planting, and on available phosphate at 8 weeks after planting. The main effect of RS application was significant on exchangeable Fe and soil pH at all observations periods.

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Phosphorus (P) often becomes limiting factor for plants growth. Phosphorus geochemistry in peatland soil is associated with the presence of peat layer and groundwater level fluctuations. The research was conducted to study the role of peat layer and groundwater level fluctuations on P concentration in peatland. The research was conducted on deep, moderate and shallow peat with sulphidic material as substratum, peaty acid sulphate soil, and potential acid sulphate soil. While P concentration was observed in wet season, in transition from wet to dry season, and in dry season. Soil samples were collected by using peat borer according to interlayer and soil horizon. The results showed that peat layer might act as the main source of P in peatland with sulphidic material substratum. The upper peat layer on sulphidic material caused by groundwater level fluctuations had no directly effect on P concentration in the peat layers. Increased of P concentration in the lowest sulphidic layer might relate to redox reaction of iron in the sulphidic layer and precipitation process. Phosphorus concentration in peatland with sulphidic material as substratum was not influenced by peat thickness. However, depletion or disappearance of peat layer decreased P concentration in soil solution. Disappearance of peat layer means loss of a natural source of P for peatland with sulphidic material as substratum, therefore peat layer must be kept in order to maintain of peatlands. [How to Cite: Arifin F, B Radjagukguk and BH Purwanto. 2014. Interaction of Peat Soil and Sulphidic Material Substratum: Role of Peat Layer and Groundwater Level Fluctuations on Phosphorus Concentration. J Trop Soils 19: 171-179. Doi: 10.5400/jts.2014.19.3.171]

Water management is main factor that determines the successful of rice cultivation in acid sulphate soil. Soil waterlogging determines the direction and rate of chemical, geochemical and biological reaction in the soil, indirectly these reactions may influence to the changes of soil psycal properties during soil waterlogging process. The experiment was aimed to study the changes of two type of acid sulphate soils physical properties during rice straw decomposition processes.  The  research  was  conducted  in  the  greenhouse  consisting  of  the  three  treatment  factors  using  the completely randomized design with three replications. The first factor was soil type: potential acid sulphate soil (PASS) and actual acid sulphate soil (AASS). The second factor was height of water waterlogging: 0.5-1.0 cm (muddy water–level  condition) and 4.0 cm from above the soil surface (waterlogged). The third factor was organic matter type: rice straw (RS), purun tikus (Eleocharis dulcis) (PT) and mixed of RS and PT (MX). Soil physical properties such as aggregate stability, total soil porosity, soil permeability, soil particle density and bulk density were observed at the end of experiment (vegetative maximum stage). The results showed that acid sulphate soil type had large effect on soil physicl properties, soil waterlogging decreased aggregate stability, soil particle density and bulk density both of soil type.Keywords : Acid sulphate soils, soil physical properties, and waterlogging [How to Cite: Arifin F, A Susilawati and A Rachman. 2014. Influence of Height Waterlogging on Soil Physical Properties of Potential and Actual Acid Sulphate Soils. J Trop Soils 19(2): 77-83. Doi: 10.5400/jts.2014.19.2.77]