Evaluating the Cu and Zn status of various rice soils of Peninsular Malaysia

Malaysia is taking efforts to be self.sufficient in rice production. However, the country is facing low availability of Cu and Zn in its soils. Even though these elements are required in small quantities for normal plant growth, their role in maximising yield is very impressive. The present study was conducted to assess the micronutrient Cu and Zn contents in selected paddy soils of Malaysia. Investigations carried out showed that marine alluvium [Guar, Sedaka, Keranji, Kuala Kedah, Kangkong, Sedu, Rotan and Kundur (Kedah)] and reverine alluvium; [Chempaka, Lubok Itek, Lating, Batu Hitam and Machang soil series (Kelantan)] were low in Cu and Zn contents. All soils were acidic in nature, with their pH values ranging from 4.3 to 6.5. Based on the results, extractable Cu and Zn concentration of soil varied within the range of 0.09.1.70 and 0.51.2.10 mg kg-1 in the soil series of Kuala Kedah and LubukItek, respectively. It was manifested that the micronutrient contents were below the critical level (Cu 0.1.1.0 mg kg-1 and Zn 0.5.3.0 mg kg-1)according to the method of extracting analysis; Mehlich.I. The sampling depth has shown a variation and the subsurface soil sampling exhibited lesser Cu and Zn contents as compared to the surface soil sampling. Findings of the research indicate that micronutrient deficiency occurs in the main rice regions of Malaysia, and this can be corrected by applying micronutrient fertiliser

Characterization of biochars produced from oil palm and rice husks and their adsorption capacities for heavy metals

The objectives of this study were to determine the selected physicochemical properties of two biochars, one commercially produced from rice husks and the other from oil palm empty fruit bunches, and to evaluate their adsorption capacities for Zn, Cu, and Pb using a batch equilibrium method. The results showed that there was no significant difference between the carbon content of biochars formed from empty fruit bunches (EFBB) and rice husks (RHB). However, the EFBB did present higher quantities of O, H, S, N, and K, compared to the RHB. Although the EFBB had a much lower surface area than the RHB, the former adsorbed much more Zn, Cu, and Pb than the RHB. The higher adsorption capacity of the EFBB over the RHB was a result of the EFBB having higher amounts of oxygen-containing functional groups, a higher molar ratio of O/C, and a higher polarity index [(O + N)/C]. This suggests that the biochar’s chemical properties were more important than its surface area in the adsorption of Zn, Cu, and Pb

Field evaluation of newly-developed controlled release fertilizer on rice production and nitrogen uptake

Implementation of sound fertilizer management in rice cultivation is essential in optimizing productivity and profitability. The use of controlled release fertilizer (CRF) to improve crop production in various cropping systems has been widely explored, with new approaches and materials continually being studied to produce new CRF. A field study was carried out to determine the efficiency of local CRFs on rice production and N uptake using MR220 CL1 rice variety. Ten different types of CRFs consisting of two groups namely biochar impregnated urea (BIU 300-5, BIU 300-10, BIU 700-5 and BIU 700-10) and palm stearin (PS) coated urea with nitrification inhibitors (PS, PS+DMPP-100, PS+DMPP-50, PS+DMPP-150, PS+Cu and PS+Zn) were used as treatments. Plant height, SPAD reading, 1000-grain weight and harvest index (HI) showed significant improvement in rice treated with both biochar impregnated and palm stearin coated urea. With respect to grain yield, BIU 300-10, BIU 700-5, BIU 700-10, PS+DMPP-100, PS+DMPP-50, PS+DMPP-150 and PS+Cu treatments significantly increased rice yield. The CRFs mostly showed significantly higher N uptake in rice, especially in rice grains, however, there was no significant difference among treatments in soil residual ammonium (NH4+-N). The newly-developed CRFs showed huge potential as an alternative for common urea, especially BIU 700-5, BIU 700-10, PS+DMPP-100 and PS+DMPP-50, in increasing rice grain yield. With proper approaches, these CRFs can contribute in improving rice production to provide sufficient food for ever increasing population

Formulation of coal fly ash and sewage sludge mixtures to reduce impacts on the environment when used as soil ameliorant for acidic Tropical soils.

Use of coal fy ash (CFA) as a soil ameliorant is hindered by the lack of macronutrients in the ash, besides, there are also concerns about its high concentration of microelements, especially boron. Sewage sludge (SS) on the other hand, has a high amount of macronutrients especially nitrogen. However, it also contains high concentrations of micronutrients especially Zn. This study was carried out to evaluate the potential of CFA as a soil ameliorant to immobilize heavy metals from SS-treated soil and whether the SS could provide supplementary macronutrients for maize growth requirement. A laboratory soil incubation study was conducted using 3 kg mixture of soil, SS and CFA. In all treatments, the SS was applied at 5% w/w. The rates of coal fy ash varied from 0, 2.5, 5, 10, 20 and 40% w/w. The soil solution was collected and analyzed weekly for pH and soluble Zn, Cu and B. A similar experiment was conducted in a glasshouse but using CFA at rates up to only 20% w/w on maize as a test plant. Although the acid neutralizing capacity of this CFA is only 0.50% of calcium carbonate equivalent (CCE), the high rates of CFA application increased the soil solution pH. Treatments of CFA at 10% and above reduced Zn concentrations in soil solution to less than 1 mg L-1. The reduction in Cu and B concentrations in the soil solution were not apparent in this study. Uptake of Zn by the maize plants was found to signifcantly decreased in treatments of 10% CFA and above. Nitrogen uptake by maize decreased in the treatment using more than 10% CFA. Only the highest treatment of CFA (20% w/w) exceeded the B toxicity level for maize (98-100 mg kg-1). Coal fy ash and sewage sludge mixture can be used as a soil ameliorant provided attention is given to the B toxicity and P and K defciency problems that might be faced by plants such as maize

Particle size and rate of biochar affected the phytoavailability of Cd and Pb by mustard plants grown in contaminated soils

Various amendments are used to reduce the phytoavailability of heavy metals in contaminated soils, but recently the use of biochar is receiving serious attention. In this study, two particle sizes of an oil palm empty fruit bunch biochar (EFBB); 2 mm (C-EFBB) were applied at either 0, 0.5, or 1% (w/w) to soils contaminated with either Cd or Pb and the phytoavailability of these metals by mustard plants grown on the soils was evaluated. Results revealed that the application of EFBB at 1% significantly increased plant growth parameters as compared with the control in Cd-soil. However, there was no significant effect of EFBB application rate on plant growth parameters in Pb-soil. There was a significant difference in the concentrations of Cd and Pb in the plant root and shoot between soils receiving different particle sizes of EFBB. The treatment of 1% F-EFBB gave the lowest concentration of the Cd concentration in the shoot (115.200 mgkg−1) and Pb concentration in the root and shoot (4196.000 and 78.467 mgkg−1, respectively) as compared with the other treatments. Therefore, F-EFBB application at high rates can be recommended for reducing the phytoavailability of Cd and Pb in contaminated soils

Sampling and analysis of chlorpyrifos airborne residue emitted under treated field conditions

Ambient air sampling on 12-hour daytime before and immediately after chlorpyrifos application using mist-blower (Solo 412) was done by passive air sampling (cotton gauze, cellulose filter and PUF) and active sampling (PUF plug and quartz filter cartridges). During spray application, sampling was also done in the air at operator breathing zone through active samplers. Samples were analysed by gas chromatography with micro electron-capture detection (GC-ʮECD) with full method validation under laboratory conditions. In the study, pre-spray measurements showed no detection of chlorpyrifos level both in active and passive air samplings. In post-spray measurements, PUF passive samplers recorded the highest level of residue detection in both post-spray sampling events in comparison to cellulose and cotton gauze. In active sampling, chlorpyrifos was detected only on PUF plug samples revealing the fact that chlorpyrifos are partitioned in the air as vapour rather than particles. The highest measured concentrations were recorded during spraying period, and then sharply declined in the post-spray periods with the passage of time. Paired comparison of performance between passive and active sampling methods in terms of residue uptake showed that passive sampling showed better performance than active sampling in this study

Airborne paraquat measurement and its exposure to spray operators in treated field environment

Airborne residue was collected for 12 h day time (4 h sampling intervals) before and after from a praquat treated field using passive patch samplers (cotton gauge, cellulose filter & PUF patches) and active samplers (quartz filter for particulates & PUF plug for vapor). Paraquat residue was detected by high performance liquidchromatographym (HPLC) with UV detector after extracting the samples according to “NIOSH method 5003” with some modification. Pre-spray measurements by both passive and active sampling showed no detection of paraquat, whereas in post-spray measurement, peak average residue level (15.56 ng cm-2) were detected on cotton gauge patches in first 0−4 h post-spray passive sampling, whereas the average residue levels detected in the second post spray event were not significantly different among the three passives patch samplers. In post spray active sampling, paraquat was detected only on quartz filter samples (not on PUF plug) revealed that in the air paraquat is associated with particles rather than vapour and paraquat air concentration was detected at higher level in first 0−4 h andsharply decline in second 4−8 post-spray period. The highest paraquat air concentration measured during the 25 min spray application at operator’s breathing zone was 125 μg m-3 that was slightly above the TLV (threshold limit value) and REL (recommended exposure limit) (100 μg m-3) of ACIGH (American Conference of Government Industrial Hygienists) andNIOSH (National Institute for Occupational Safety & Health, 1994). In addition, potential dermal and inhalation exposure dose (theoretically) estimated by extrapolating air residue data showed higher value than the proposed aacceptable operator exposure level (0.0005 mg kg-1 day-1)

Short-term field decomposition of pineapple stump biochar in tropical peat soil.

The transformation of biochar on tropical peat is yet to be studied as all previous studies have been conducted on mineral or forest soils. The objectives of this study were to investigate the physical and chemical changes experienced by pineapple stump biochar (PSB) in tropical peat and to determine the short-term decomposition model of PSB in a C-rich environment. Elemental composition was determined using CHNS-O analyzer and surface area with Brunauer-Emmett Teller (BET) method. Surface chemistry and structural study were conducted with Fourier Transform Infrared (FTIR) spectroscopy and 13C solid state Nuclear Magnetic Resonance (NMR) spectroscopy, respectively. The PSB short-term decomposition was conducted with a litter bag study and best fitted into the hyperbolic decay model compared to exponential decay model because no significant mass loss was detected after 4 months. The stagnant phase was probably due to interaction with metals from peat. Redox reaction was prominent on the surface and structural chemistry. Surface oxidation of PSB produced more O-functionalities (hydroxyl, carboxylic and phenolic) and achieved chemical recalcitrance after 12 months. The carbon structure was reduced or saturated causing a decrease in electronegativity. Further PSB decomposition probably depends on biotic decomposition

Characterization of empty fruit bunch biochar pyrolyzed at different temperatures with respect to activated carbon and their sorption capacities for pentachlorophenol

Pentachlorophenol (PCP) has been used extensively in the wood preservation industry. It is highly persistent in the environment and toxic to living organisms. The present study investigated the effectiveness of an oil palm empty fruit bunch biochar (EFBB) pyrolyzed at 350, 550 and 650°C in adsorbing PCP as compared to a commercial activated carbon (AC). The ash content, surface area and aromaticity increased while the pore volume, cation exchange capacity, O/C and (O+N)/C molar ratios decreased as the pyrolysis temperature increased. Only the EFBB pyrolyzed at 350°C and the AC adsorbed the PCP while no PCP adsorption was observed on the EFBBs pyrolyzed at 550°C and 650°C. The Langmuir maximum adsorption capacity (Qmax) values was 6.035 mg g−1, and 126.582 mg g−1 for the 350°C EFBB and the AC, respectively. The higher porosity and more oxygenated functional groups of the EFBB pyrolyzed at 350°C EFBB could be the reason for its ability to adsorb the PCP compared to the other EFBBs. The high PCP sorption by the AC on the other hand, could be attributed to its high surface area and microporous structure

Boron fertilizers borax and colemanite application on rice and their residual effect on the following crop cycle

Boron (B) is one of the essential micronutrients and its deficiencies occur over a range of soils and crops. The effectiveness of borax and colemanite as B sources for two seasons of rice crop under flooded acidic soil were evaluated in a field study. We studied the direct and residual effects of borax, powder colemanite (PC) and granular colemanite (GC) fertilizers which were applied to rice crop at the rates of 0, 1, 2, and 3 kg B ha−1. One application of B significantly increased the growth and yield of crop for two seasons. Results of the first season field experiment showed that application of borax and PC at 3 kg B ha−1 improved all plant growth parameters, B concentration in spikelet and rice yield over the control and other B rates. Residual B from borax and PC significantly increased the plant height, number of tillers and panicles per plant, number of grains per panicle and weight of 1000 grains compared to the control. However, the residual GC showed no significant effect on plant growth parameters. Residual borax and PC at 3 kg B ha−1 produced higher yield than the levels of 1 and 2 kg B ha−1. Yield difference between residual borax and PC was not significant at 3 kg B ha−1, although at 2 kg B ha−1, PC produced significantly higher yield than the borax. Both of these B sources were found to be equally effective in supplying B to rice crop for two seasons. The PC was more efficient than GC in supplying B to rice due to its finer particle size making it more water soluble