Tropical Peat Soil Research Articles

Effect of potassium on growth, yield and quality of pineapple in tropical peat

Introduction. Two field experiments were conducted to investigate the effects of potassium (K) on plant growth, fruit yield and quality of pineapple cultivated on tropical peat soil. Materials and methods. Six levels of K: 0, 266, 532, 798, 1064 and 1330 kg ha-1 K2O were applied at each of two pineapple plantations located at two different sites. The experiments were conducted with the Gandul cv. in a randomized complete block design with three replications. Results and discussion. The application of K had not any significant effect on plant height and leaf number of pineapple at both sites. Potassium significantly influenced the fruit diameter at site 1, and fruit length and fruit weight at site 2. The application of 266 kg ha-1 K2O resulted in the highest fruit weight and, at site 2, further increase of K declined it. Potassium had no significant effect on fruit sugar and acidity. However, at site 2, acid content tended to increase with increased K applications. Conclusion. Potassium applications at high rates tended to depress most of the growth and yield attributes of cv. Gandul pineapple cultivated on peat soil in Malaysia.

Effects of Land-Use Change in Tropical Peat Soil on the Microbial Population and Emission of Greenhouse Gases

Effects of land-use change in tropical peatlands on the microbial population and emissions of nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) were studied in the field and laboratory. The study area covered secondary forest, paddy field and paddy-soybean rotation field in Indonesia. ATP content, and numbers of viable bacteria and fungi, cellulolytic bacteria and fungi, NH4+ oxidizers and denitrifiers in a paddy-soybean rotation field and paddy field were reduced to 1-30% and 3-90% of those in secondary forest, respectively. The field measurements of greenhouse gas emissions showed that significantly more CH4 was emitted from paddy field than secondary forest, but no significant difference in the emission of either N2O or CO2. The laboratory incubation experiment showed that the soil moisture level and land-use change significantly affected the emission of N2O, CH4 and CO2. These results suggested that land-use change significantly affected the microbial population and emissions of greenhouse gases.

2-11 Cupric oxide oxidation products of tropical peat soils

2-11 Cupric oxide oxidation products of tropical peat soils

Effect of converting wetland forest to sago palm plantations on methane gas flux and organic carbon dynamics in tropical peat soil

The effect of changing wetland forest to sago palm plantations on methane gas flux and organic carbon dynamics in tropical peat soil was studied in the field and the laboratory using soil samples from the Peat Research Station, Sarawak, Malaysia. A small amount of methane was released from the soil surface of both the forest and plantation field, with no significant difference between the two sites (1·1±0·61 and 1·39±0·82 mg CH4 m−2 hr−1, respectively); thus, the amount of methane emission from the total area of tropical peat soil was estimated, preliminarily, as 2·43 Tg yr−1, contributing 0·45% of the total global methane emission and 2·1% of methane emissions from global natural wetland. However, large amounts of methane were accumulated in the deeper soil layers. Sago palm contained much less carbon as biomass, but lost more as the carbon dissolved in groundwater. Laboratory experiments showed that incorporation of rice straw into tropical peat soil increased methane formation significantly. Conversely, ammonium sulfate suppressed methane formation in tropical peat soil. Copyright © 1998 John Wiley & Sons, Ltd.

Effect of converting wetland forest to sago palm plantations on methane gas flux and organic carbon dynamics in tropical peat soil

The effect of changing wetland forest to sago palm plantations on methane gas flux and organic carbon dynamics in tropical peat soil was studied in the field and the laboratory using soil samples from the Peat Research Station, Sarawak, Malaysia. A small amount of methane was released from the soil surface of both the forest and plantation field, with no significant difference between the two sites (1.1 ± 0.61 and 1.39 ± 0.82 mg CH 4 m -2 hr -1 , respectively); thus, the amount of methane emission from the total area of tropical peat soil was estimated, preliminarily, as 2.43 Tg yr - 1 , contributing 0-45% of the total global methane emission and 2.1% of methane emissions from global natural wetland. However, large amounts of methane were accumulated in the deeper soil layers. Sago palm contained much less carbon as biomass, but lost more as the carbon dissolved in groundwater. Laboratory experiments showed that incorporation of rice straw into tropical peat soil increased methane formation significantly. Conversely, ammonium sulfate suppressed methane formation in tropical peat soil.

Nutritional characteristics of sago palm and oil palm in tropical peat soil

To make clear the nutritional characteristics of sago palm (Metroxylon sagu Rottb.) and oil palm (Elaeis guineensin Jacq.) grown in tropical peat soil, minerals concentration, organic compounds concentration, and photo‐synthetic rate were estimated, and the obtained results were as follows. Since, the nitrogen (N), phosphorus (P), calcium (Ca), magnesium (Mg), and sodium (Na) concentration in mature leaves and trunk were higher in the oil palm than in the sago palm, but potassium (K) concentration was higher in the sago palm than in the oil palm, the minerals (especially N, P, Ca, and Mg) requirement for the oil palm were higher than in the sago palm. This indicates that the sago palm will adapt better than the oil palm to soils with poor nutrients. The manganese (Mn) and zinc (Zn) concentration in leaves of the sago palm and Ca and aluminum (Al) concentration in leaves of the oil palm increased with the increase of aging, indicating that those elements are eliminated from plants through leaf senescence. In the sago palm, the N and P distribution ratio to leaves remained almost constant during growth, indicating that N and P were predominantly distributed to leaves for maintaining leaf function. The photosynthetic rate [μmole carbon dioxide (CO2) m2 LA sec‐1] at light saturation was lower in the sago palm (5.8) and oil palm (10.0) than in wheat (25.4). As leaf longevity of sago and oil palms was longer (about 12 times) than that of wheat (Triticum aevstium L.), and the minerals concentration and photosynthetic rate remained constant for a long duration of growth, the cumulative carbon (C) accumulation per unit dry weight (photosynthetic rate x leaf longevity) in the individual leaf is assumed to be equal or greater than that of wheat. The photosynthetic ability of sago and oil palms leaves is very important for understanding why sago and oil palms have high productivity in spite of a low nutrient environment.

Nutritional Environment of Tropical Peat Soils in Sarawak, Malaysia Based on Soil Solution Composition

Abstract It has been considered that natural peat soils and swamp forest ecosystems in the tropics are quite oligotrophic. This concept seems to be related to the low mineral contents in the soil solid phase of the peat soils. However, some nutritional elements such as K, Mg, Ca, and/or P may be abundant in the soil solution phase and could easily migrate in peat soils. In order to analyze the nutritional environment of peat soils, chemical composition of the soil solid phase and soil solution was compared. This study was carried out in Naman Forest Reserve, Sibu and in/around Sg. Talau Peat Research Station, Mukah, Sarawak, Malaysia. In both areas, each of the three study sites with a different depth of underlying mineral layer was selected for sampling of soil and soil solution. All the soils studied except for one shallow peat profile were classified into Oligotrophic peat based on Fleischer’s criteria. The soil solution collected monthly showed the following characteristics in its composition. 1. Conc...

Chemical variables affecting the lime requirement determination of tropical peat soils

Abstract The carboxyl group in humic acid (HA) is the major functional group influencing the soil acidity. The soil pH(H2O), %HA, buffer capacity, milliequivalent (meq) COOH, meq phenolic OH, and meq total acidity/100 g peat are significantly correlated with lime requirement (LR). The LR of peat soils with high soil pH is low regardless of the effect of other variables (%HA, meq COOH, meq phenolic OH, meq total acidity/100 g peat, and buffer capacity). This indicates that the soil pH(H2O) is an important factor influencing the LR of tropical peat soils. MiUiequivalent COOH/g HA is inadequate criteria for determining peat soil acidity component as it changes with humification. However, meq COOH/100 g peat (meq COOH/g HA x %HA) is significantly correlated with LR and this implies the importance of %HA as soil acidity component in tropical peat soils. Buffer capacity is significantly correlated with %HA, meq COOH, meq phenolic OH, and meq total acidity/100 g peat. Stepwise multiple regression analysis indica...

Distribution of heavy metals among different bonding forms in tropical peat soils

Abstract The objective of this study is to analyze the characteristics of the macro- and micro-nutrient status of tropical peat soils under natural swamp forest and their changes after reclamation. We sampled peat soils from the coastal swamps in southern Thailand and southern Peninsular Malaysia. These soils were at varying stages of reclamation. Soil Fe, Mn, Zn, and Cu were sequentially divided into water soluble, Ca exchangeable, free-oxide-associated, weakly complexed, strongly complexed, carbonate-associated, and sulfide-associated extractable forms. Peat soils sampled in Malaysia were classified into Oligotrophic peat soils due to their low N, P, K, and Ca contents. The Ca, Mg, K, and Na contents did not change appreciably with the soil depth, though the Mn, Zn, and Cu contents decreased with the soil depth down to 30 cm and subsequently the decrease was negligible. Based on the analysis of the distribution of the metal forms, most of Cu and Fe occurred in strongly chelated and non-extractable forms. Average contents of water soluble and Ca exchangeable forms (intensity factor) of Mn, Zn, and Cu were 12, 4, and < 0.1 mg kg-1 of soils, respectively. In the case of fertilized soil (experimental field of MARDI), heavy metal contents of the surface soil were about 3 to 15 times as high as those of the subsoil. Most of the increment occurred in the weakly chelated, strongly chelated, or non-extractable forms, because the pH of the surface soil was higher than that of the subsoil. As the chelating effect of humic substances is likely to be pronounced for a high soil pH, heavy metals applied in fertilizers were changed into non-available forms. Adsorption strength of humic substances in peat for metal ions was as follows: Cu > Fe > Zn > Mn.

Chemical alterations of tropical peat soils determined by Waksman's proximate analysis and properties of humic acids

Abstract The objective of this study is to analyze the chemical characteristics of tropical peat soils under natural swamp forest and their changes after reclamation. Peat soils were sampled from coastal swamps in southern Thailand and southern Peninsular Malaysia. These soils were at various stages of reclamation. The contents of water-soluble constituents in plant materials such as polysaccharides, tannins, and hemicellulose decreased with the soil depth due to leaching from subsoils below the water table. In the surface soil, readily decomposable organic constituents, namely polysaccharides, tannins, hemicellulose, and cellulose were decomposed and converted into humic acids during the first 5 y of reclamation. The humification degree of the newly formed humic acids increased in the succeeding 10 y of reclamation. Multiple regression of the pyrophosphate index, which reflects the decomposition stages of peat soils, and some other variables for their relevant characters were computed. Decreasing amounts of cellulose and lignin and increasing amounts of humic acids were found to be suitable variables for expressing the humification processes (r 2 = 0.82). As a result of an NMR study, humic acids of tropical peat were considered to have long aliphatic chains, because they are likely to be partially derived from aquatic algae.

Lime requirement determination of tropical peat soil using buffer‐pH methods

Abstract A study was conducted to calibrate and evaluate five buffers for the lime requirement (LR) determination of tropical peat soil. The buffers tested were the Shoemaker‐McLean‐Pratt (SMP); Mehlich; 0.1M ammonium acetate (NH4OAc); 0.1M barium acetate [(Ba(OAc)2]; and 0.1M calcium acetate [Ca(OAc)2]. Calibration was done by comparing the precision of linear regression equations adjusted to the relationships between the LR rates required to achieve pH 5.0 measured in a 1: 4 (soiltwater) ratio as determined by incubation and soil‐buffer pH values. Incubation LR using calcium carbonate (CaCO3) to achieve pH 5.0 by peat soil was utilized to calibrate each buffer. Evaluation was carried out by assessing the LR from the calibrated buffers which estimate the LR nearest to the target pH of 5.0. The calibration study showed that the SMP and Mehlich buffers were less precise than the Ba(OAc)2, NH4OAc, and Ca(OAc)2 buffers. The evaluation study indicated that the Ba(OAc)2 buffer is the most accurate, followed by...

Surface charge and adsorption characteristics of copper and zinc on tropical peat soils

Abstract The surface charges and the adsorption of copper (Cu) and zinc (Zn) on tropical peat soils which are poorly documented were investigated as a function of solution pH and Cu and Zn equilibrium concentrations. The point of zero charge of tropical peat soils from Malaysia and Thailand was lower than the original soil pHs. The adsorption of Cu and Zn remarkably increased with the increase of the solution pH and the equilibrium concentrations following the Langmuir adsorption isotherm equation. The adsorption of Cu on tropical peat soils was larger than that of Zn at the same pH value which was controlled with an automatic pH regulator. The relationship between the proton release and Cu and Zn adsorption was in the range of 1 to 2, suggesting that Cu and Zn replaced one or two protons from the sites with proton adsorption of tropical peat soils, although the proton consumption by hydrolytic Cu and Zn ions in the solution and dissociated carboxyl groups of tropical peat soils caused the decrease in the...

Inhibitory effect of canal water drained from a tropical deep peat soil on the elongation of rice roots

Abstract Water culture experiments, a laboratory experiment and a field survey were conducted to analyze the effect of canal waters drained from tropical woody peat areas distributed in Peninsular Thailand on the elongation of rice roots and to determine whether some toxic compounds were present in the waters. The results obtained are summarized as follows. 1. Root elongation of rice plant was strongly inhibited when rice was grown in the canal water drained from the Bacho deep peat area, which contained a high concentration of phenolic compounds, at a low pH and low Cu concentration whereas it was not inhibited in the canal water drained from the To Daeng shallow peat area, which contained a low concentration of phenolic compounds. 2. Inhibition of the root elongation by the Bacho canal water was alleviated by the increase of pH and by Cu application. It was considered that the inhibition of root elongation was induced by the toxicity of phenolic compounds. 3. When Cu was added to the canal water, most o...

Fertilizer Responses of Cucumbers on Peat in Brunei

SUMMARYThe effects on local cucumbers of supplementary mineral fertilizers over an initial field dressing of 30 tonnes of poultry manure and 4 tonnes of lime/ha, were determined on tropical peat soil in Brunei. Significant yield increases were obtained with supplementary N up to 280 kg/ha but not with K/Mg above the basal rates 78/10 kg/ha. The highest yields exceeded 50 tonnes/ha of marketable fruit, obtained over a 9-week growing period.