S. R. Syed Omar

Analysis of heavy metals during composting of the tannery sludge using physicochemical and spectroscopic techniques

The major limitation of direct application of tannery sludge compost in agriculture is the total heavy metal contents and their bioavailability to the soil-plant system. This study focused on the heavy metal characterization and the influence of changing the physicochemical properties of the medium throughout the composting on the concentrations, bioavailability or chemical forms of Cr, Cu, Zn, Pb and Cd in tannery sludge. The study shows that throughout the 60 days of composting, physicochemical analysis and Fourier-transformed infrared (FTIR) spectroscopic characterization show that all parameters elaborated and reached relatively stable levels reflecting the stability and maturity of the final product, and revealed the biodegradation of components that can be easily assimilated by microorganism. The C/N ratio reaches the optimal range of stable compost; inorganic nitrogen is transformed into stable organic forms. The total concentration of Cr, Zn, Cu, Pb and Cd is very low rendering final compost acceptable for agricultural use. The germination index for both Chinese cabbage and lettuce was 97% after 60 days of composting, showing that the final compost was not phytotoxic. Furthermore, in using a sequential extraction method in sludge compost at different phases of treatment, a less than 2% of metals bound to bioavailable fractions X-(KNO(3)+H(2)O). A large proportion of the heavy metals were associated to the residual fraction (75-85%) and more resistant fractions to extraction X-NaOH, X-EDTA, X-HNO(3) (15-25%). Mobile fractions of metals are poorly predictable from the total content. Bioavailability of all fractions of elements tends to decrease.

Evaluation of controlled-release compound fertilizers in soil

Evaluation of compound controlled-release fertilizer (CRF) in the soil is essential in order to establish an appropriate soil management and fertilizer application technique. A compound fertilizer containing about 15% nitrogen (N), 2% phosphorus (P), 16% potassium (K), 4% calcium (Ca), 1% magnesium (Mg), and 1% copper (Cu) was prepared and subsequently coated with natural rubber (NR), polyvinyl chloride (PVC), polyacrylamide (PA), and polylactic acid (PLA). Evaluations of the compound CRF were conducted in the laboratory and in the field using an open leaching technique. The soil column was prepared using an acid Bungor soil (Typic Paleudult) packed in PVC tube for the laboratory and an undisturbed soil column for the field studies. A 25-g sample of each coated fertilizer was mixed with the soil in the top (0–60 mm) of the soil column. Nutrients released by the compound CRF in the appropriate soil column were monitored in the leachate for 30 d (about 18.0 pore volume (PV) of leachate), while in the field they were exposed to the atmosphere for about 90 d. The uncoated compound fertilizer gave significantly (P≤0.05) higher amount of nutrient loss compared to the coated fertilizers during leaching in the laboratory. The values ranged from 3023.0 mg N (80.3% of that added) to 1.4 mg Cu (6.2% of that added). Among the coated fertilizers, there were wide variations in the amounts and types of nutrient losses between different coating materials. By taking the summation of nutrients in the leachate, the effectiveness of the uncoated and coated compound fertilizers decreased in the order: PVC≈NR>PLA>PA⋙uncoated. Depth distribution of nutrients and their amounts remaining in the soil column of the respective treatments showed no significant difference between leaching in the laboratory and that in the field. Thus, the effectiveness of the compound uncoated and coated fertilizers was similar to that measured in the laboratory using a fraction collector. Therefore, an assessment of the CRF could be done precisely and accurately in the laboratory using an open leaching technique. However, the effectiveness of CRF needs to be validated in the presence of a growing plant.

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.

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.

Changes in Properties of Composting Rice Husk and Their Effects on Soil and Cocoa Growth

The worldwide production of rice husk, a by‐product and agrowaste that causes serious environmental problems, may reach 116 million t y−1. The objectives of this study were (i) to determine the physicochemical changes of rice husk and its structural chemistry during composting using 13carbon nuclear magnetic resonance (13C NMR) and (ii) to determine the effect of the composted rice husk (CRH) on the properties of Oxisol and cocoa (Theobroma cacao L.) growth under glasshouse conditions. Results showed an active composting phase occurred at the first 53 days as revealed by high carbon dioxide (CO2)‐C (40–71 µg g−1 h−1) production, followed by a matured composting phase occurring at 54–116 days as revealed by decreasing in CO2‐C production (10 µg g−1 h−1). The active composting was accompanied by increases in electrical conductivity (EC), pH, ammonium (NH4 +), and nitrate (NO3), whereas during the matured composting phase, the EC and cation exchange capacity increased but pH, NH4 +, and NO3 −1 decreased. The ash of the produced compost contains mainly calcium (Ca), potassium (K), sulfur (S), magnesium (Mg), and phosphorus (P) as essential nutrients. The CP/MAS 13C NMR spectra before and after various composting times indicated the dominance of sharp and well‐resolved signal peaks at O‐alkyl C and di‐O‐alkyl C regions (67–73%), which are characteristic of cellulose. The percentage of N‐alky/methoxyl was 23–26% whereas phenolic, carboxyl, and alkyl C types were less than 3% each. The application of the CRH to an Oxisol significantly increased soil pH and Ca, Mg, K, sodium (Na), and silicon (Si) ions of in situ soil solution but decreased the amounts of toxic ions [aluminum (Al), manganese (Mn), and iron (Fe)]. The CRH was found to increase cocoa growth up to 37%.

ALUMINUM SPECIATION OF AMENDED ACID TROPICAL SOIL AND ITS EFFECTS ON PLANT ROOT GROWTH

Exchangeable and soluble soil aluminum (Al) is limiting plant growth in many soils worldwide. This study evaluated the effects of increasing rates of dolomite and magnesium carbonate (MgCO3) on Al3+, pH, dissolved organic carbon, cations, anions, and Al speciation on oil palm Deli dura × AVROS pisifera root growth. Dolomite and MgCO3 additions significantly raised linearly soil solution pH, magnesium (Mg2+), nitrate (NO3 −) and chlorine (Cl−) concentrations; exponentially decreased the activity of phytotoxic Al species [aluminum (Al3+), aluminum sulfate (Al2SO4), and aluminum fluoride (AlF3)]; and reduced manganese (Mn) concentration and activity. High activity of those species exponentially reduced root dry weight. Optimum oil palm growth was achieved at: <50 μM monomeric Al, < 30 μM Mn, and <0.20 unit of the ratio Al+Mn to calcium (Ca)+Mg. High activity of Al species and Mn in acidic soil solution cause significant reduction of the root growth. Soil acidity alleviation either with dolomite or MgCO3 mitigates the toxic effect of Al and Mn.

Changes in Gibberellic Acid (GA3) Content in Oryza sativa Due to Paclobutrazol Treatment

An UV spectrophotometric area under curve method was developed for the estimation of Levofloxacin Hemihydrate in its mono component tablets. The spectrophotometric method for estimation employed Area under curve method for analysis using 0.1M Sodium Hydroxide as solvent for the drug Levofloxacin Hemihydrate at the wavelength range of 285-295nm. Levofloxacin Hemihydrate obeys Beer’s law in concentration range 10-50µg/ml. The recovery studies ascertained accuracy of the proposed method and the result validated according to ICH guideline. Results of analysis have been valid statistically by recovery studies. The method was successfully for evaluation of Levofloxacin Hemihydrate in tablet dosage form without the interference of common excipients.

ALLEVIATION OF ALUMINUM IN ACIDIC SOILS AND ITS EFFECT ON GROWTH OF HYBRID AND CLONAL OIL PALM SEEDLINGS

Aluminum (Al) toxicity is an important factor in limiting crop production. The present study examined the Al alleviation effects on the growth of hybrid (breeding) and clonal (tissue culture) of D × P oil palm seedlings. The experiment was performed using calcium carbonate (CaCO3), and ground magnesium limestone (GML) and magnesium carbonate (MgCO3) as soil-amendments at different rates in Colombia and Malaysia, respectively. The effects of the treatments were evaluated monthly on vegetative variables and visual symptoms. Chlorophyll concentrations were recorded in Malaysia at the fifth month growing stage. The different amendments improved the soil fertility and it was reflected on better performance of shoot and root growth. The chlorophyll content in the frond number 3 for both materials enhanced significantly when Al saturation was low (0–30%). The results from the experiment revealed the importance of neutralization of Al in reducing its toxicity in oil palm.

Phosphorus Fertilizer use in Pineapple Cultivation with in situ Residues Burning on Organic Soils

Abstract In Malaysia, pineapples are grown on peat soils, but most phosphorus (P) fertilizer recommendations are made without due quantification of P uptake; the distribution of P in roots, stem, leaves, peduncle, fruit, and crown; or loss through leaching even though P retention in peat soils is low. This study was conducted to determine applied P‐use efficiency under a conventionally recommended fertilization regime in pineapple cultivation with in situ residues burning before replanting. Results showed that most of the P uptake in pineapple can be found in the fruit, stem, leaves, and crown, but the general trend of P distribution was in the order of fruits>leaves>stem>crown>peduncle>roots. Phosphorus recovery in pineapple cultivation was about 40%, and this low recovery was attributed to leaching. Hence, fertilizer recommendations need to take into consideration P loss through leaching. This will help to increase P‐use efficiency because it is not possible to build up P content of peat soils. As a result, the need to assess the possibility of side‐dress applications of phosphatic fertilizers on peat soil is necessary.