J. Shamshuddin

Effects of limestone and gypsum application to a Malaysian ultisol on soil solution composition and yields of maize and groundnut

A field experiment was conducted on an Ultisol in Malaysia to assess changes in soil solution composition and their effects on maize and groundnut yields, resulting from limestone and gypsum application. The results showed that soil solution Ca in the lime treatment remained mainly in the zone of incorporation, but in the gypsum treatment some Ca moved into 15–30 cm zone. Al3+ and AlSO4+ were dominant Al species in the soil solution of nil treatment. Liming decreased Al3+ and AlSO4+, but increased hydroxy-Al monomer activities. However, gypsum application resulted in an increase of AlSO4+ activity and in a decrease of Al3+ activity.Relative maize and groundnut yields were negatively correlated with Al3+, Al(OH)2+ and Alsum activities. Likewise, relative yields were negatively correlated with Al concentration and the Al concentration ratio and positively correlated with soil solution Mg concentration and Ca/Al ratio.

A laboratory study of pyrite oxidation in acid sulfate soils

Abstract Acid sulfate soils cover an estimated 13 million hectares (ha) worldwide, the largest concentration (6.7 million ha) being in the coastal lowlands of Southeast Asia. In Malaysia, they occur mainly along the coastal plains of Peninsular Malaysia and Sarawak. Soils that have been drained are characterized by very low pH and high amounts of exchangeable aluminum (Al), both resulting from the oxidation of pyrite. This article explains the transformation of pyrite when pyrite-bearing sediments present in acid sulfate soils undergo weathering. Soil samples containing pyrite from Cg-horizons of selected acid sulfate soils in Peninsular Malaysia were incubated in the laboratory. Some samples were treated with peat, superphosphate, calcium silicate, or dolomite so as to reduce the oxidation of pyrite. Some were left unamended as a control. Changes in pyrite morphology were studied by scanning electron microscopy-energy dispersive x-ray (SEM-EDX). At the end of incubation period, water-soluble metals were determined. Pyrite in the unoxidized state has iron (Fe) to sulfur (S) ratio of 1:2, indicating the absence of heavy metal contamination in the pyrite structure. This suggests that when pyrite dissolves, there is little risk of pollution with respect to heavy metals. Pyrite dissolved quickly to form jarosite as its disintegration proceeded. The amounts of aluminum and iron in the water-soluble form were large, possibly reaching plant and aquatic life toxic levels. The application of superphosphate slowed down pyrite oxidation.

Alleviation of Aluminum Toxicity in an Acid Sulfate Soil in Malaysia Using Organic Materials

In Peninsular Malaysia, acid sulfate soils are commonly distributed in the coastal plains. Some of these soils are planted to crops, but the yield, which is attributed to soil infertility related to aluminum (Al) toxicity. For acid sulfate soils, liming to eliminate Al toxicity is not practical. Application of organic materials to overcome the Al toxicity is considered a better option. Research conducted to determine the efficacy of organic matter to ameliorate acid sulfate soil infertility is few. Hence, this study was carried out. The results showed that Al was reduced substantially by addition of organic materials especially green manure and green manure in combination with peat. The mixture of peat and organic materials significantly lowered total and monomeric Al concentrations. Peat mixed with organic materials (especially green manure and rice straw) synergistically promoted complexation and chelation of monomeric Al, presumably forming Al–organic acid complex in the soil. The relative root length (RRL) of mungbean was negatively correlated with various Al indices. The RRL of mungbean increased with decreasing total and monomeric Al concentration, Al3 + activities, monomeric Al activities, [Al3 + + AlOH2 + + Al(OH)2 +], [3Al3 + + 2AlOH2 + + Al(OH)2 +], aluminum activity ratio (AAR) and Al activity equivalent ratio (AER). The monomeric Al activities and Al3 + activities to maintain 90% RRL were respectively 1.21 and 0.35 µM.

Alleviation of soil acidity in Ultisol and Oxisol for corn growth

Malaysian Ultisols and Oxisols are characterized by low pH, high soil solution Al concentration and Ca and/or Mg deficiencies, which are limiting to corn growth. An experiment was conducted to determine the changes in solid and soil solution phase properties of a representative Ultisol and Oxisol following applications of ground magnesium limestone (GML), gypsum and their combinations, and their effects on corn growth. A plot of pAl against lime potential (pH-1/2 pCa) showed that the points were mostly positioned between the theoretical lines for kaolinite-quartz and gibbsite equilibrium, reflecting the kaolinitic-oxidic mineralogy of the Ultisol and Oxisol. Gypsum application increased Al concentration in the soil solutions of the Ultisol, but had no significant effect on that of the Oxisol. The increase in Al concentration in the Ultisol was due to an increase in ionic strength. Gypsum application increased soil solution pH of the Oxisol due to release of OH as a result of ligand exchange between SO4 and OH ions on the oxides of Fe and/or Al. Exchangeable Al in both soils was reduced by gypsum application. The reduction was associated with solid phase immobilization through alunite formation; the soil solutions of soil samples treated with 2 and 4 t gypsum ha−1 were supersaturated with respect to alunite. Application of GML at 2 t ha−1 together with 1–2t gypsum ha−1 gave high top weight of corn. Relative top weight of corn was positively correlated with a soil solution Mg and Ca/Al concentration ratio, but negatively correlated with soil solution Al concentration. Foliar Al corn was positively correlated with soil solution Al concentration. Soil solution Al and Mg concentrations, and Ca/Al concentration ratio can be used as indices of soil acidity in Ultisols and Oxisols. ei]{gnB E}{fnClothier}

Andisols On Volcanic Ash From Java Island, Indonesia: Physico-chemical Properties And Classification

Java Island in Indonesia is dominated by volcanic ash soils. A study was conducted to characterize the soil’s physico-chemical properties in order to assess the influence of change of parent material on differing soil characteristics along an E-W sequence. All of the soils are Andisols of varying chemical composition. Soil pH and exchangeable Ca decreased from East to West Java, attributable to the parent ash becoming more acid from east to west. However, the Si, Al, and Fe extracted by acid-oxalate and the estimated amounts of allophane (11–35%) and ferrihydrite in the fine earth increased from east to west, showing that development of active forms of Al and Fe is favored by strongly leaching environments. This trend holds true for the point of zero net charge (PZNC) and for pHo. Samples rich in allophane showed relatively high PZNC. The relatively high pHo values for the Central and West Java soils indicate development of net positive variable charges at pH < pHo. East Java and Kopeng soils are capable of holding more basic cations than the other soils at the actual soil pH. Therefore, these soils are less likely to be deficient in Ca and Mg under yearly application of acidifying nitrogenous fertilizers.

Growth of Cocoa Planted on Highly Weathered Soil as Affected by Application of Basalt and/or Compost

Oxisols, which are highly weathered, occupy a large area of Malaysia. These soils are infertile because of low pH, calcium (Ca), magnesium (Mg), and potassium (K) levels but high aluminum (Al) content. The infertility can be ameliorated by applying soil amendments. A study was conducted to determine the effects of basalt and/or rice husk compost application on cocoa growth planted on an Oxisol. The results showed that either basalt or rice husk compost and their combinations were effective ameliorants. Basalt application increased soil pH and exchangeable Ca and Mg while decreasing exchangeable Al. Accordingly, soil solution Ca, Mg, and K increased and Al and manganese (Mn) concentrations decreased. Silicate released from basalt was able to lower the pHo (the pH at which the net charge of the variable charge minerals is zero), indicating a negative charge was being generated, which led to increase in the cation exchange capacity (CEC) of the Oxisol. The improvement in soil fertility because of application of the amendments had improved cocoa growth. Leaf K and P of the cocoa planted on the basalt-treated soils were within the sufficient range for cocoa growth. Rice husk compost applied at a rate of less than 20 t ha−1 in this trial was not able to supply sufficient N to the cocoa. Basalt application at an appropriate rate effectively ameliorates acidic soil infertility, but it takes time to realize the positive effects of application as it slowly dissolves under field conditions.

Determination of the Geochemical Weathering Indices and Trace Elements Content of New Volcanic Ash Deposits from Mt. Talang (West Sumatra) Indonesia

Since the Indonesian archipelago is part of the very active and dynamic Pacific Ring of Fires, the volcanic eruptions occur from time to time. Immediately after the eruption of Mount Talang in West Sumatra (April 12, 2005), volcanic ashes, both unleached and leached were collected. The deposits from Mt. Talang were andesitic to basaltic in composition. The volcanic ash consisted of volcanic glass, plagioclase feldspar in various proportions, orthopyroxene, clinopyroxene, olivine, amphibole, titanomagnetite. We conducted the total elemental analysis of the bulk samples of the volcanic ash. The contents of major, trace and rare elements as well as heavy metals were determined by wet chemical methods and x-ray fluorescence (XRF) analyses. Although the volcanic ash of Mt. Talang are still very new, an evaluation of the geochemical weathering indices was performed with the objective of showing the volcanic ash condition at the early stage of weathering. Eight weathering indices were evaluated. The results showed that the unleached volcanic ash has higher Ruxton Ratio (R), Weathering Index of Parker (WIP), Product of Weathering Index (PWI) and Silica Titanium Index (STI) values compared to the leached ash, while the leached ash exhibited higher Chemical Index of Alteration (CIA), Chemical Index of Weathering (CIW), Vogt’s Residual Index (VO), and Plagioclase Index of Alteration (PIA). These weathering indices can be used to quantify the condition of the volcanic ashes at the initial stage of weathering, to evaluate their fertility, to provide a better understanding of element mobility during weathering, and predict the source of soil nutrients as well as determine the products of primary minerals alteration.

Changes in chemical properties and growth of corn in volcanic soils treated with peat, ground basalt pyroclastics, and calcium silicate.

Volcanic ash-derived soils have high pH0 and very low cation exchange capacity attributed to their highly reactive colloidal constituents, the short-range-order minerals. Fertility is in doubt unless the effects of positive adsorption sites are masked and the increment of negative charge improved. Laboratory and glasshouse experiments were conducted to assess the masking effects of peat, ground basaltic pyroclastic and calcium silicate viz. effect on pH0 and CEC of volcanic soils of Camiguin Island, the Philippines, and to evaluate the growth of corn (Zea mays L.) grown on these soils after the treatments. In the laboratory experiment, Andic Haplumbrept (Soil 1) and Typic Dystrochrept (Soil 2) were incubated with 20% (air-dried) peat, ground basaltic pyroclastic and calcium silicate for nine months. In the glasshouse experiment, the treatments consisted of four rates of the above materials: 20, 10, 5, and 0% per unit weight soil. Corn was planted after nine months of incubation period. The results showed that incubation with peat reduced pH0, increased the CEC, and improved their ion retention. Addition of ground basaltic pyroclastic improved the charge properties but indicated that more incubation time is needed to get an optimum effect. Calcium silicate effect was uncertain due to a relatively high application rate. Corn response showed that nutrient uptake increased with the applied amendments. It also showed that relative plant heights and weights were linearly correlated with Mg concentration in the soil solution.

Pore Space And Specific Surface Area Of Heavy Clay Oxisols As Affected By Their Mineralogy And Organic Matter

Pores and specific surface area (SSA) play a major role in controlling transport systems and potential reactivity of soils, but they have received little attention for heavy clay Oxisols. The objectives of this study were: (i) to study the pore sizes and SSA of heavy clay Oxisols as affected by their mineralogy and soil organic matter (SOM); and (ii) to determine the mechanism of SOM stabilization in a dark-colored Oxisol (Kuantan soil). The mineralogy of the clay fraction was studied by X-ray diffraction, differential thermal analysis, and scanning electron microscopy, whereas soil organic C was determined by combustion technique. Pores and SSA were measured by N2 adsorption-desorption technique. Results showed that the clay fraction of the three Oxisols studied varied from 73% to 82%. The minerals in this soil fraction were kaolinite, goethite, hematite, and gibbsite in varying amounts. Under natural conditions (SOM was not removed by hydrogen peroxide), the pores were dominated by mesopores (2-50 nm). Partitioning the mesopores into various sizes showed that the cumulative small mesopore (2-20 nm) volume was considerably higher for Kuantan (63%-73%) than the S. Mas or Segamat (25%-35%) soils. This is caused by the lower crystallinity and smaller size of minerals in the former. The values of SSA were compatible with those of the soil pores as exhibited by the SSA with and without SOM, which were 1.6 to 1.9 and 2.0 to 2.2 times higher, respectively, in Kuantan than in S. Mas or Segamat soils. Stabilization of SOM in Kuantan soil occurred through physical protection in the mesopores and cation bridging, as revealed by the increase in mesopore volume (from 58% to 92%) after SOM removal and the high Fep and Alp contents, respectively. The less crystalline and smaller clay size particles present in the heavy clay Oxisols have a positive impact on soil carbon sequestration and stabilization.

Bio-Fertilizer, Ground Magnesium Limestone and Basalt Applications May Improve Chemical Properties of Malaysian Acid Sulfate Soils and Rice Growth

Acid sulfate soils are normally not suitable for crop production unless they are appropriately ameliorated. An experiment was conducted in a glasshouse to enhance the growth of rice, variety MR219, planted on an acid sulfate soil using various soil amendments. The soil was collected from Semerak, Kelantan, Malaysia. Ground magnesium limestone (GML), bio-fertilizer, and basalt (each 4 t ha−1) were added either alone or in combinations into the soil in pots 15 d before transplanting. Nitrogen, P and potash were applied at 150, 30, and 60 kg ha−1, respectively. Three seven-day-old rice seedlings were transplanted into each pot. The soil had a pH of 3.8 and contained organic C of 21 g kg−1, N of 1.2 g kg−1, available P of 192 mg kg−1, exchangeable K of 0.05 cmolc kg−1, and exchangeable Al of 4.30 cmolc kg−1, with low amounts of exchangeable Ca and Mg (0.60 and 0.70 cmolc kg−1). Bio-fertilizer treatment in combination with GML resulted in the highest pH of 5.4. The presence of high Al or Fe concentrations in the control soil without amendment severely affected the growth of rice. At 60 d of growth, higher plant heights, tiller numbers and leaf chlorophyll contents were obtained when the bio-fertilizer was applied individually or in combination with GML compared to the control. The presence of beneficial bacteria in bio-fertilizer might produce phytohormones and organic acids that could enhance plant growth and subsequently increase nutrient uptake by rice. Hence, it can be concluded that addition of bio-fertilizer and GML improved rice growth by increasing soil pH which consequently eliminated Al and/or Fe toxicity prevalent in the acid sulfate soil.