Mohd Khanif Yusop

Enhancement of nitrogen release properties of urea–kaolinite fertilizer with chitosan binder

The use of controlled release fertilizer (CRF) has become a new trend to minimize environmental pollution. In this study, urea–kaolinite containing 20 wt% urea after one hour dry grinding was mixed with different concentrations of chitosan as a binder to prepare nitrogen-based CRF. Fourier transform infrared spectroscopy confirmed the hydrogen bonding between urea and kaolinite. Covalent interaction between urea–kaolinite and chitosan make the granules stronger. The nitrogen release was measured in 5 days interval using a diacetylmonoxime calorimetric method at a wavelength of 527 nm. The results illustrated that by increasing the chitosan concentration from 3 to 7.5%, nitrogen release decreased from 41.23 to 25.25% after one day and from 77.31 to 59.27% after 30 days incubation in water. Compressive stress at break tests confirmed that granules with chitosan 6% had the highest resistance and were chosen for ammonia volatilization tests. Ammonia volatilization was carried out using the forced-draft technique for a period of 10 weeks. The results showed that the total amount of ammonia loss for conventional urea fertilizer and urea–kaolinite–chitosan granules was 68.63 and 56.75%, respectively. This controlled release product could be applied in agricultural crop production purpose due to its controlled solubility in the soil, high nutrient use efficiency and potential economic benefits.

Mining and Development of Novel SSR Markers Using Next Generation Sequencing (NGS) Data in Plants

Microsatellites, or simple sequence repeats (SSRs), are one of the most informative and multi-purpose genetic markers exploited in plant functional genomics. However, the discovery of SSRs and development using traditional methods are laborious, time-consuming, and costly. Recently, the availability of high-throughput sequencing technologies has enabled researchers to identify a substantial number of microsatellites at less cost and effort than traditional approaches. Illumina is a noteworthy transcriptome sequencing technology that is currently used in SSR marker development. Although 454 pyrosequencing datasets can be used for SSR development, this type of sequencing is no longer supported. This review aims to present an overview of the next generation sequencing, with a focus on the efficient use of de novo transcriptome sequencing (RNA-Seq) and related tools for mining and development of microsatellites in plants.

Preparation of encapsulated urea-kaolinite controlled release fertiliser and their effect on rice productivity

Abstract Urea-intercalated kaolinite containing 20 wt% urea was granulated and coated with water-based epoxy resin to prepare nitrogen-based controlled release fertiliser (NCRF). The nitrogen release property was studied using UV-Vis spectroscopy through the diacetylmonoxim colorimetric method for different samples of granules of urea-intercalated kaolinite and non-intercalated urea–kaolinite mixture. Also the effect of granules size and different coating thickness on nitrogen release from coated NCRFs was investigated. The results of release experiments revealed that intercalation of urea into kaolinite caused a three times decrease in the nitrogen release compared to non-intercalated sample. Also, by increasing the size of granules and thickness of coating, the nitrogen release ratio from NCRFs decreased. Finally, a glasshouse trial was conducted to evaluate the effect of coated urea-kaolinite compared with a non-coated one and conventional urea fertiliser granules on rice productivity (Variety MR 219). The yield together with some yield component data (filled spikelet, spikelet per panicle, productive tiller) revealed a highly significant and positive response to coated CRF N fertiliser treatment (one time application). Also, the pooled data of the yield and yield component emphasised that the rice crop responded significantly to treatments involving CRF nitrogen fertilisers as compared to others. The maximum grain yield of 28.73 g/pot belongs to coated CRF, medium grain yield of around 21.74 g/pot from the non-CRF N fertilisers plots and the lowest yield was obtained where conventional urea was applied. The other morphological and physiological characters show a similar trend to the yield.

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.

Sulfur and molybdenum fractionation in marine and riverine alluvium paddy soils

Abstract Intermittently submergence and drainage status of paddy fields can cause alterations in morphological and chemical characteristics of soils. We conducted a sequential fractionation study to provide an insight into solubility of Sulfur (S) and Molybdenum (Mo) in flooded alluvial paddy soils. The samples (0–15 and 15–30 cm) were taken from marine and riverine alluvial soils in Kedah and Kelantan areas, respectively, and were sequentially extracted with NaHCO3, NaOH, HCl, and HClO4–HNO3. Total S in upper and lower layers of Kedah and Kelantan ranged between 273 and 1121 mg kg−1, and 177 to 1509 mg kg−1, respectively. In upper layers and subsoil of Kedah, average total Mo were 0.34 and 0.27 mg kg−1, respectively. Average total Mo in Kelantan were 0.25 mg kg−1 (surface layer) and 0.28 mg kg−1 (subsoil). Cation exchange capacity (CEC) was positively correlated with plant available amounts of Mo in upper layers of Kedah area. Also, total and medium-term plant-available S was correlated with total carbon (C) at lower layers of Kelantan soil series. But in surface layers of Kelantan soil series, CEC was strongly correlated with total and medium-term plant-available S. Our results indicates that the influence of flooding conditions on soil S and Mo contents in paddy fields may cause long-term changes in S and Mo chemical reactivities.

Sulfur uptake and translocation in maize (zea mays) grown in a high pH soil treated with elemental sulfur

ABSTRACT A glasshouse experiment was conducted to elucidate the influence of elemental sulfur (S) application rates (0, 0.5, 1.0, and 2.0 g S kg−1 soil) on the release and uptake of S at 0, 20, and 40 days after incubation. Results showed that there was a progressive upward trend in maize leaves, stem, and root S content with application of elemental S. However, maize production followed a nonlinear model. Plants grown in untreated soils suffer from S deficiency and addition of elemental S at a rate of 0.5 g S kg−1 soil alleviated S deficiency. The decrease in maize performance due to the highest S application rate was not related to S toxicity. The greatest leave, stem, and root productions were obtained at S concentrations of 0.41, 0.58, and 0.2%, respectively. Overall, application of elemental S at a rate of 0.5 g S kg−1 soil is recommended for maize performance improvement.

Efficiency of Coated Urea on Nutrient Uptake and Maize Production

ABSTRACT A field experiment was conducted to study the effects of coated urea with urease inhibitor [copper (Cu) and zinc (Zn)], nitrification inhibitor (DMPP), biochar and geopolymer on ammonium, nitrate, Cu, Zn content and crop yield of maize. The treatments were composed of urea alone (control), urea coated Cu and Zn (UCuZn), urea coated with Cu, Zn, and DMPP (UCuZnDMPP), urea impregnated with biochar (Ubio) and urea coated with geopolymer (Ug2). Data showed that treatments with Cu, Zn, and DMPP produced lower ammonium (NH4) and nitrate (NO3) in UCuZn and UCuZnDMPP while they had the highest concentration of Cu and Zn in soil and plant tissues. Plots treated with UCuZn and UCuZnDMPP produced maximum N concentrations in grains and yield, with increases by 79.5% and 74.1%, respectively, as compared with urea (control). This finding demonstrates that by slow down the hydrolysis and nitrification process using urease and nitrification inhibitor were beneficial to increased N uptake, ultimately produced higher yield.