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Articles by O.H. Ahmed
Total Records ( 12 ) for O.H. Ahmed
  N. Abdullahi , J.B. Sidik , O.H. Ahmed and M.H. Zakariah
  The increasing importation of starch in Malaysia for poultry and bio-processing industries is a call for concern. The development and released of improved cassava genotype (Sri Pontian) in 2003 by the Malaysian Agricultural Research and Development (MARDI) was a good step to enhance cassava productivity. Sri Pontian was reported to show higher yield than those of Manihot Mardi 92 and Sri Medan (the popular table variety). Such claim has not been verify in East Malaysia. This research was carried out to verify the aforementioned claim by comparing selected yields attributes of Manihot Mardi 92, Sri Medan and Sri Pontian at Bintulu, Sarawak, East Malaysia. This study was conducted at experimental field of University Putra Malaysia Bintulu Campus Sarawak from July to December, 2011. The experimental design was a randomized complete block with three replications. The three varieties evaluated were: Manihot Mardi 92, Sri Medanand Sri Pontian. These varieties were planted on ridges with three planting methods: Vertical planting (forming 90° angle to the ridges), incline planting (forming 45-60° angle to the ridges) and horizontal planting (forming 180° to the ridges). Variations among the varieties were observed for number of shoots retained per plant, leaf longevity, leaf area index, number of storage roots formation and fresh storage roots yield. Significant interaction effect between variety and planting method was observed for all the variables tested, except for number of shoots retained per plant and number of storage roots per plant. All varieties showed similar number of shoots per plant regardless of planting method except for Sri Pontian which had lowest effect with respect to number of storage roots formation per plant in incline planting. Similarly, leaf longevity in Sri Pontian was the lowest regardless of planting method. Sri Medan showed the greatest leaf area index, number of storage roots formation per plantand fresh storage roots yield. The effect of Manihot Mardi 92 in terms of leaf area index, number of storage roots formation per plantand total storage roots yield in vertical planting was comparable to that of Sri Medan. Sri Pontian had the lowest storage roots yield. This study showed in East Malaysia, Sri Medan was identified as the best genotype with good agronomic attributes. This variety has the potential to increase cassava productivity over a wide range of environmental conditions.
  M.H. Akbar , O.H. Ahmed , A.S. Jamaluddin , N.M. Nik Ab. Majid , H. Abdul-Hamid , S. Jusop , A. Hassan , K.H. Yusof and Arifin Abdu
  Problem statement: The soil properties of tropical rain forest in Southeast Asia have been characterized by several researchers; however empirical data on soil characteristics under rehabilitation program are still limited or even lacking. This research is important to determine the soil physical and chemical properties of a rehabilitated degraded forest land 19 years after planting with various indigenous species in comparison with adjacent secondary forests and to elucidate the soil fertility status in rehabilitated and secondary forests by using Soil Fertility Index (SFI) and Soil Evaluation Factor (SEF). Approach: Soil samples were collected from both locations which were rehabilitated forest and secondary forest (Nirwana forest) at University Putra Malaysia, Bintulu Sarawak Campus. The plot size of each experimental site was 20x20 m. An auger was used to take soil samples from two depths, namely 0-10 and 10-20 cm. For soil profile, the soil samples were collected from different depths up to 100 cm according to the soil horizons. The samples were air-dried, homogenized and sieved to pass a 2 mm mesh sieve for further analysis. The physical analysis consisted of bulk density and soil moisture content. For chemical analysis, soil acidity, soil organic matter, total organic carbon, available P, exchangeable Al, exchangeable ammonium and nitrate, exchangeable cations (Ca, Mg, K) and Cation Exchange Capacity (CEC) were determined. The soil fertility status was determined based on SFI and SEF values for both rehabilitated and secondary forests. Results: The bulk density of the rehabilitated forest ranged between 0.70 and 1.29 g cm-3 and that of the secondary forest was 0.64-0.76 g cm-3. The soil moisture content of the rehabilitated forest was 23.31-51.03% while that of secondary forest was 41.06-41.49%. The range pH (water) of the rehabilitated forest was 4.5-5.0 and that of the secondary forest range was 4.2-4.3. Furthermore, the content of SOM in the rehabilitated forest was 2.5-5.8%. On other hand, the range for the secondary was 4.1-4.6%. The exchangeable Al of the rehabilitated forest was 0.8-2.5 cmolckg-1 and that of the secondary forest was 1.6-1.7 cmolckg-1. The CEC of the rehabilitated forest was 1.4-11.8 cmolckg-1, while that of the secondary forest was 4.3-4.5 cmolckg-1. Based on SFI and SEF values, the secondary forest had a lower fertility status compared to the rehabilitated forest. Moreover, the SEF value of the secondary forest was below 5, while some of the plots of rehabilitated forest had the SEF values greater than 5. Conclusion: It can be concluded that both rehabilitated and secondary forests have significant differences based on selected physical and chemical properties. Moreover, the soil fertility status at rehabilitated plots was comparatively higher than secondary forest indicating a good potential of ‘Miyawaki’ forest rehabilitation technique in rehabilitating and replenishing soil fertility status of degraded forest land.
  C.P. Auldry , O.H. Ahmed , A.M. Nik Muhamad , H. Mohammad Nasir and M. Jiwan
  Problem statement: Agriculture waste such as Sago Waste (SW) has a potential to cause pollution when the waste is discarded into rivers. In order to add value to SW, a study was conducted to produce potassium and calcium hydroxide, compost and Humic Acid (HA) from SW. Approach: The SW was air-dried and some grinded. The grinded SW was incinerated at 600°C. Potassium and calcium hydroxide was extracted by dissolving the ash in distilled water at a ratio of 1:500 (ash: water), equilibrated for 24 h at 150 rpm using a mechanical shaker and filtered. The ungrinded SW was used for compost production. The compost was produced by mixing SW (80%) + chicken feed (10%) + chicken dung slurry (5%) + molasses (5%). Results: The hydroxide extracted from ash of SW was used to isolate HA of composted SW. The molarity and pH of the hydroxide were 0.002M and 10 respectively. Calcium (42.88 mg kg-1) and potassium (29.51 mg kg-1) content were high in the hydroxide compared with other elements. The compost took about 60 days to mature. There was an increased in pH, ash, Cation Exchange Capacity (CEC) and HA and a decreased in temperature, C/N ratio, C/P ratio and organic matter. The hydroxide was able to extract 1% of HA from the composted SW. A comparison between the yields of HA extracted from the composted SW using the hydroxide of the SW and that of the analytical grade showed no statistically difference. The chemical characteristics of HA from the composted SW were in standard range. Conclusion: Potassium and calcium hydroxide, compost and HA can be produced from sago waste. Low morality of the hydroxide is able to produce good quality of HA from composted sago waste. The HA can be reconstituted with K and Ca from potassium and calcium hydroxide to produce K-Ca-humate and this needs to be investigated as a form of organic based fertilizer.
  B.T. Saga , O.H. Ahmed , A.S. Jamaluddin , H. Abdul-Hamid , S. Jusop , N.M. Nik Ab. Majid , A. Hassan , K.H. Yusof and Arifin Abdu
  Problem statement: The tropical rain forests in Southeast Asia have been characterize by several researchers. However empirical data on soil characteristics under degraded forest land in tropical rain forest and rehabilitated program are limited. A study was conducted to evaluate the soil orphology, mineralogical and sesquioxide properties of a rehabilitated degraded forest land (19 years after it was planted with various indigenous species) in comparison with an adjacent secondary forest. Approach: Soil samples were air-dried and pass through a 2 mm sieve. Soil morphology was determined based on field observation. The non-crystalline (amorphous) of Al, Fe and Si oxides and hydroxides (Alo, Feo and Sio) were extracted with ammonium oxalate while the Dithionate-Citrate- Bicarbonate (DCB) method was used for extracting (crystalline) the Al, Fe and Si oxides and hydroxides (Ald, Fed and Sid). The concentrations of extracted Al, Fe and Si were determined by atomic absorption spectroscopy. Mineralogical compositions were identified by X-ray diffraction method. Results: The A-horizon of secondary forest was darker and thicker than that of the rehabilitated forest. Root mat at the secondary forest was well-developed compared to the rehabilitated forest. The clay minerals were dominated with kaolinite and illite to a lesser extent of goethite and hematite accompanied with low values of activity ratio of Al and Fe oxides and hydroxides, indicating that the soils were highly weathered. Conclusion/Recommendations: The difference between rehabilitated and secondary forests was root abundance where secondary forest had most. Good root penetration in the secondary forest indicates that the soil texture there was not heavy. Soils in the rehabilitated and secondary forests were strongly weathered (high presence of kaolin minerals), but the low presence of sesquioxides suggests that they are yet to reached the ultimately weathered phase. The soil properties in terms of morphology, sesquioxides and clay minerals should be taken into account for better management of forest rehabilitation program in tropical regions.
  K. Ellyfa , O.H. Ahmed , S. Shaharudin and D. Abdul Rahman
  Observation on the morphological effects and estimation of LD50 for a snap bean (Phaseolus vulgaris) upon irradiating snap bean seeds with different doses of gamma rays was done in this study. The seeds were treated with 0, 300, 400, 500, 600 and 800 Gy doses of gamma irradiation by the Malaysian Institute of Nuclear Technology (MINT). These treatments (30 seeds per treatment) were replicated three times and plants monitored by standard procedures. The study started in December 2006 and ended in February 2007. Standard procedures were used to observe and record the variables studied in this research. Increasing dosage of gamma irradiation was accompanied by decrease in height, root length, oven-dry weight of root, shoot and survival of snap bean. It was also found that the LD increased with increasing gamma radiation. Other changes observed in this study were leaflet and chlorophyll mutation. Generally, gamma irradiation greatly induced morphological changes in snap bean.
  M.C. Law , S.K. Balasundram , M.H.A. Husni , O.H. Ahmed and Mohd. Haniff Harun
  This study aimed at quantifying the spatial variability of Soil Organic Carbon (SOC), estimating SOC at unsampled locations and comparing the spatial variability of SOC between young and mature oil palm stands. Two study sites were chosen to represent two different palm age groups, i.e., 5 Years after Planting (YAP) and 17 YAP. A systematic sampling design was employed for soil sampling at the 0-20 cm depth based on a cluster of four palms that comprised three operational zones: Weeded Circle (WC), Frond Heap (FH) and Harvesting Path (HP). A total of 60 sampling clusters were obtained for each site. Soil samples were analyzed for SOC by dry combustion method. All measurement points were geo-referenced by differential Global Positioning System (dGPS). The SOC data were first explored using descriptive statistics, normality check, outlier detection and data transformation, followed by variography and interpolation. Spatial variability of SOC was mapped based on measured and kriged values. Results showed that all operational zones exhibited a definable spatial structure, which were described by either spherical or exponential models. All operational zones exhibited strong spatial dependence. Operational zones of 5-year old palms exhibited a shorter effective range than those of 17 year old palms. Additionally, SOC heterogeneity was evident among operational zones at both sites, where FH registered the highest SOC, followed by WC and HP. SOC concentration at 17 year old palms was found to be more stable than that from 5 year old palms. This study suggests spatial variability assessment appears to be a feasible technique to quantify the variability of SOC in oil palm cultivation.
  O.H. Ahmed , H. Aminuddin and M.H. A. Husni
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  M.C. Law , S.K. Balasundram , M.H.A. Husni , O.H. Ahmed and Mohd. Hanif Harun
  This study aimed at quantifying the spatial variability of SOC and estimating SOC concentration in oil palm. This study was carried out in a commercial oil palm plantation bearing 27 year old palms. A systematic design was employed for soil sampling at the 0-20 cm depth based on a cluster of 4 palms that included three operational areas Weeded Circle (WC), Frond Heap (FH) and Harvesting Path (HP). A total of 60 sampling clusters were established. SOC was analyzed using dry combustion method. All measurement points were geo-referenced by a differential Global Positioning System (dGPS). The SOC data were first explored using descriptive statistics, normality check and outlier detection. This followed by variography and interpolation techniques to quantify the spatial variability of SOC. Results showed that all three operational areas exhibited a definable spatial structure and were described by either spherical or exponential models. SOC from WC and HP showed moderate spatial dependence while that from FH showed a strong spatial dependence. The FH had a shorter effective range than other operational areas. Contour maps for WC, FH and HP clearly showed spatial clustering of SOC values. All three operational areas fulfilled the interpolation accuracy criteria. This study suggests that site-specific management could be considered as a strategy to increase SOC sequestration in oil palm.
  M.C. Law , S.K. Balasundram , M.H.A. Husni , O.H. Ahmed and Mohd. Hanif Harun
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  O.H. Ahmed , M.H.A. Husni and M.M. Hanafi
  This study was carried out to determine the efficiency using applied P under a conventional recommended fertilization regime in pineapple cultivation with residue removal. Results showed that P recovery from applied P fertilizer in pineapple cultivation on tropical peat soil was 53%. At 0-10 cm depth, there was a sharp decrease of soil total P, extractable P and soil solution P, days after planting for plots with P fertilizer. This decline continued till the end of the study. Soil total, extractable and solution P at the end of the study were generally equal to those before the study. There was no significant accumulation of P at 10-25 and 25-45 cm depths. However, P concentrations throughout the study period were generally lower or equal to their initial status. Recovery of P in pineapple cultivation on tropical peat soil seems to relate to P loss. As such, P loss needs to be considered in fertilizer recommendations for pineapple cultivation in organic soils.
  O.H. Ahmed , M.H.A. Husni , M.M. Hanafi , S.R. Syed Omar and A.R. Anuar
  This study was carried out to investigate whether relationships could be established among total P, extractable P and soil solution P under fertilized and unfertilized conditions for unburned pineapple residue management practices in pineapple cultivation on tropical peat soils. Results showed that the relationship among total P, extractable P and soil solution P for the fertilized condition was quadratic at 0-10 cm depth. There was no significant relationship at the same depth for the unfertilized condition. There was no relationship among the three forms of P for both of the fertilized and unfertilized conditions at 10-25 cm and 25-45 cm depths. This observation was attributed to low bulk density and leaching of P. Only top soil under fertilized condition affects the nature of the relationship among total, exchangeableand soil solution P in pineapple cultivation tropical peat soils.
  S.K. Balasundram , M.H.A. Husni and O.H. Ahmed
  Quantification of spatial variability is a vital prerequisite for precision agriculture. This study was aimed at quantifying the spatial variability of selected chemical properties in a tropical peat cultivated with pineapple. A 1-ha study plot was established in a commercial pineapple plantation in Simpang Rengam, Johor. Georeferenced topsoil samples (n = 60) were obtained systematically from 8x18 m spacings in the x and y direction, respectively. These samples were tested for total C, extractable P, K, Cu, Zn and B. Soil data were first explored using univariate statistics, including normality check, non-spatial outlier detection and data transformation. This was followed by variography and kriging analyses to quantify the spatial variability of chemical properties. Results revealed a high degree of spatial variability in the majority of chemical properties, which exhibited non-normal distributions with CVs ranging from 12 to 54%. All properties exhibited a definable spatial structure, which were described by either spherical or exponential models. Carbon, P and B showed strong spatial dependence. The majority of properties had a short effective range. Surface maps of chemical properties clearly showed spatial clustering of test values. Excepting K, all other properties showed acceptable accuracy of interpolated values. These combined data suggest the need for a site-specific approach in managing tropical peat cultivated with pineapple, particularly with regard to nutrient management.
 
 
 
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