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Articles by Osumanu Haruna Ahmed
Total Records ( 8 ) for Osumanu Haruna Ahmed
  Osumanu Haruna Ahmed , Aminuddin Husin and Ahmad Husni Mohd Hanif
  Ammonia volatilization from surface-applied urea fertilizer reduces N fertilizer use efficiency by crops. Beneficial formation of NH4 over NH3 leading to reduction of NH3 loss may be possible through addition of zeolite and acidic materials. The objective of this laboratory study was to evaluate the effect of four different urea-triple superphosphate (TSP)-zeolite mixtures on NH3 volatilization and NH4 and NO3 contents in soil, compared with surface-applied urea without additives. The soil was a sandy clay loam Typic Kandiudults (Bungor Series). The mixtures significantly reduced NH3 loss by 34 to 49% compared with urea (straight urea, 46% N) and larger reductions were obtained with higher rates of zeolite (0.75 and 1 g kg-1 of soil). All the mixtures of acidic P fertilizer and zeolite with urea significantly increased soil NH4 content but not NO3 content. The mixtures with acidic P fertilizer and zeolite also significantly increased soil-exchangeable Ca, K and Mg, and benefited the formation of NH4 over NH3 compared with urea without additives. The increase in soil-exchangeable cations, and temporary reduction of soil pH, might have impeded urea hydrolysis in the microsite immediately around the fertilizer. It could be possible to improve the efficiency of urea surface-applied to high value crops by addition of TSP and zeolite.
  Mohamadu Boyie Jalloh , Wan Sulaiman Wan Harun , Jamal Talib , Mohd Fauzi Ramlan , Rajan Amartalingam , Christopher Teh Boon Sung and Osumanu Haruna Ahmed
  Abstract: Problem statement: Intercropping has been shown to have many advantages but it is fallacious to conclude it is always a better cropping system. Little is known about a new double-hedgerow intercropping of rubber, banana and pineapple in relation to its effects on growth and yield of the component crops when compared to their monocrops. Simulation modeling offers a cheaper and faster alternative to explore cropping scenarios and estimate their productivity under a wide range of management and environmental conditions. This simulation study was therefore undertaken to evaluate the growth and yield of immature rubber, banana and pineapple intercrop and monocrop scenarios with the aid of an intercrop simulation model named SURHIS, as well as estimating the intercropping advantage. Approach: A FORTRAN computer model (SURHIS) that simulated the daily light interception and utilization by immature-rubber, banana and pineapple intercropping system was used to simulate intercrop and monocrop scenarios to estimate potential Dry Matter Yield (DMY) for all crops as well as fruit yields for banana and pineapple. The results of the model were tested for accuracy by comparing actual field experimental results with the aid of Mean Deviation (MD) and Mean Absolute Error (MAE) statistical analyses. Intercropping advantage was assessed using the Land Equivalent Ratio (LER) analysis. Results: The model was representative or predicted DMY of the crops with sufficient accuracy. The LER analysis showed that the intercropping system had a dry matter yield productivity advantage of 81% more than monocrops of the component crops. The results also showed that the higher the Plant Population Density (PPD), the greater is the dry matter yield. It was also shown that banana and pineapple had no deleterious effect on the growth of rubber. Fruit weight per plant of banana and pineapple was reduced with increase in PPD for the monocrops. Measured average fresh fruit bunch weight for banana was 18 kg plant-1 and the average fresh fruit weight per plant for pineapple was 2.1 kg for the intercropping system. Conclusion: Intercropping of banana and pineapple with immature-rubber is more productive than the component crops grown as monocrops in their respective optimum plant population densities per hectare. The model can be useful for predicting potential productivity, with sufficient accuracy, of the afore-mentioned intercropping system under varying plant density and environment scenarios as well as acting as a guide for plant density experimentation.
  Franklin Ragai Kundat , Loo Hong Shen and Osumanu Haruna Ahmed
  Problem statement: Various methods are used to counter the population of Cyperus iria in rice fields and among the most common method are chemical approaches. Chemical control methods are preferred by rice farmers due to their efficacy, speed, ease of storage and affordable cost. The concern of chemical herbicides is on its effects on the environment. Less attention had been given to biological control methods. Limitations such as host specificity, formulations and storage requirements are some of the obstacles that have to be overcome before implementation. Although it is environmentally friendly, a total shift from chemical control methods to biological seems unreasonable. Therefore incorporation of biological control with reduced chemical herbicides is expected to produce a better and sustainable control of weeds. Approach: A study was conducted to determine the potential of using Exserohilum rostratum as a biocontrol agent (incorporated with chemical herbicide, bentazone) to control Cyperus iria. The biocontrol agent (E. rostratum) was confirmed to be pathogenic to C. iria by applying Koch’s postulates. Preliminary laboratory experiments were carried out to ensure the interactions within the mixture was not inhibitory. Results: Bentazone was confirmed to be compatible with E. rostratum with an ED50 value of 22064570.0 μgai mL-1. In order to determine the efficacy of the incorporations, several mixtures were tested in a greenhouse environment. It was found that the mixtures of E. rostratum (106 spores mL-1) with bentazone (0.4 kgai ha-1) was significantly a better control of Cyperus iria compared to the usage of bentazone alone (0.4 kgai ha-1) and spores alone (106 spores mL-1). It was significantly more effective than the mixture of RBD palm oil (10%), Tween 80 (5%) and spores (106 spores mL-1) which acted as the conventional bioherbicide approach. Synergistic effects were exhibited with 50% less herbicide concentrations from the recommended rates. The mixture exhibited 50% disease severity in 3.5 days compare to bentazone alone which requires 4.9 days and the conventional bioherbicide mixture was relatively less effective requiring 4.7 days. The mixture of spores alone required 7.6 days to achieve 50% disease severity. This suggests that the mixture can save 50% of the cost on bentazone while providing a faster control. Conclusion: The incorporations were confirmed to be successful in providing a better and environmentally friendlier method than the conventional methods of weed control.
  Anton Eko Satrio , Seca Gandaseca , Osumanu Haruna Ahmed and Nik Muhamad Ab. Majid
  Problem statement: It is important to compare the effect of extremely different rainfall conditions on soil carbon storage of lowland tropical peat swamp forest. Therefore, under these natural rainfall gradient, the objectives of this study were to determine whether rainfall affects soil carbon storage of a tropical peat swamp forest and to determine what correlations between variables occurs which stimulate soil carbon storage changes of a tropical peat swamp forest. Approach: Soil sampling was conducted in two different plots (0.3 ha each plot) to a depth of 15 cm under two extremely different mean rainfall at Sibu, Sarawak, Malaysia. The soil samples were analyzed for acidity, organic matter content, total carbon, total nitrogen and total phosphorus. The humic acid extraction was also done and soil carbon storage values were obtained by calculation. The calculation of carbon storage was by the bulk density method. Comparison between paired means of soil carbon storage under two different rainfall gradients were tested using paired t-test and correlation analysis was used to correlate variables (pH, soil organic matter, total carbon, total nitrogen, total phosphorus, C/N ratio, C/P ratio, humic acid yield, unstable carbon and stable carbon). Results: The percentage of stable carbon count of unstable carbon was 42.93% under lower rainfall, while that of higher rainfall was 62.69 %. It suggests that this natural tropical peat swamp forest plays an important role as a sink rather than a source of carbon under higher rainfall but inversely under lower rainfall. It also suggests that soil organic matter tends to decompose and releases CO2 by oxidation under lower rainfall. Stable carbon positively correlated with humic acid yield for the two areas with different rainfall (p<0.01, r = 1.00). However, under higher rainfall, stable carbon also positively correlated with soil organic matter (p<0.05, r = 0.42) and total carbon (p<0.05, r = 0.42). It was found that stable carbon negatively correlated with soil acidity on both higher (p<0.05, r = -0.51) and lower rainfall areas (p<0.01, r = -0.54). However, that association appeared prominent under lower rainfall. Conclusion: Anaerobic environment is more prominent under higher rainfall and may facilitate high value of soil carbon storage in the soil profile of tropical peat swamp forest and allow this ecosystem to function as a carbon sink. During lower rainfall, water availability in tropical peat swamp forest may stimulate this ecosystem to maintain its soil acidity by releasing more CO2 in soil air and becomes a source rather than a sink of carbon.
  Zuraidah Yahya , Aminuddin Husin , Jamal Talib , Jamarei Othman , Osumanu Haruna Ahmed and Mohamadu Boyie Jalloh
  Problem statement: Introduction of mechanisation in oil palm (Elaeis guineensis) plantations could result in soil compaction and cause soil degradation. This could be a serious problem in the future due to increase in size, weight and transportation frequency of machines used. Objectives: This trial was carried out to evaluate the effect of different trailer weights and transportation frequencies on the soil physical properties of Bernam series soil. Approach: The treatments were a combination of three trailer weights and four transportation frequencies. At the end of 6 years of the experiment, soil samples were taken for soil physical properties characterisation at 0-10, 10-20 and 20-30 cm depths. Results: After six years of soil compaction treatments, the results showed that the mean soil bulk density increased and the porosity decreased annually. However, the mean soil bulk density was still less than 1.0 g cm-3. The mean soil bulk density decreased with increasing soil depth, but porosity and available water increased with soil depth. The 3 rounds per month transportation frequency for all trailer weights and 2 rounds per month for the 4 tonnes trailer weight significantly affected the soil physical properties. Conclusion: Generally, the results indicated that the 6 years of compaction treatments did not cause serious soil compaction that could alter the soil physical properties for this particular soil type.
  Anton Eko Satrio , Seca Gandaseca , Osumanu Haruna Ahmed and Nik Muhamad Ab. Majid
  Problem statement: There is still lack of a study that compares the soil carbon storage of kuda-kuda skidding system and excavator skidding system in tropical peat swamp forests. The objective of this study was to determine whether skidding operations affects soil carbon storage of a tropical peat swamp forest. Approach: Soil sampling was conducted on two different plots (0.3 ha each plot) to a depth of 15 cm under different skidding systems at Sibu, Sarawak, Malaysia. Plots were in the same forest concession area but considerably independent from each other. The soil samples were analyzed for acidity, organic matter content, total carbon, total nitrogen and total phosphorus. The humic acid extraction was also done and soil carbon storage values were obtained by calculation. The calculation of carbon storage was by the bulk density method. Unpaired t-test was used to compare variables under the two systems and correlation analysis was used to correlate variables (pH, soil organic matter, total carbon, total nitrogen, total phosphorus, C/N ratio, C/P ratio, humic acid yield, unstable carbon and stable carbon). Results: Soil organic matter, total carbon and unstable carbon were found to be negatively correlated with nitrogen but positively correlated with C/N ratio under kuda-kuda skidding system indicating that the lower nitrogen and higher C/N ratio markedly slowed decomposition process and enabled soil organic matter to accumulate as well as total carbon. Unstable carbon stocks under excavator skidding system was found to be higher (130.200 Mg ha-1) compared with kuda-kuda skidding system (117.124 Mg ha-1), under kuda-kuda skidding system, unstable carbon stock seemed to be preserved better and this was because of the better carbon storage. Although stable carbon contents of the two systems were similar, the excavator skidding system had faster decomposition processes, thus unstable carbon stocks decomposed more and this probably affects its function as carbon storage for further periods. Total phosphorus positively correlated with nitrogen but negatively correlated with C/N ratio under kuda-kuda skidding system, indicating that low nitrogen (0.914%) results in high C/N ratio (55.236) and this may have affected phosphorus (0.024%), thus enabled organic material to accumulate instead of losses through decomposition process. The low phosphorus (0.024%) or high C/P ratio (2346.345) under kuda-kuda skidding system resulted in decreased soil pH (3.552), thus enabled soil organic matter (97.603%) and total carbon (48.802%) to accumulate as well as unstable carbon stocks (117.124 Mg ha-1). Conclusion: The application of skidding systems in this peat swamp forest possibly alters their carbon storage particularly unstable carbon by altering their decomposition rates. Kuda-kuda skidding system is able to maintain decomposition process in this peat swamp forest. Hence, unstable carbon stocks can be preserved for further persistent breakdown processes, hence maintaining their function for carbon storage.
  Anton Eko Satrio , Seca Gandaseca , Osumanu Haruna Ahmed and Nik Muhamad Ab. Majid
  Problem statement: Since heavy machinery are used in the logging operation activity for extracting the logs on sensitive forest site with peat soil, environment destruction should be the other concern during its processes especially on its important function as soil carbon storage. The objective of this study was to determine whether logging operation affect soil carbon storage of a tropical peat swamp forest. Approach: Soil sampling was conducted before and after logging operation in a 0.3 ha plot to a depth of 15 cm. The soil samples were analyzed for acidity, organic matter content, total carbon, total nitrogen and total phosphorus. The humic acid extraction was also done and soil carbon storage values were obtained by calculation. Paired t-test was used to compare variables under the two treatments (before and after logging) and correlation analysis was used to correlate variables such as soil pH, soil organic matter, total carbon, total nitrogen, total phosphorus, C/N ratio, C/P ratio, humic acid yield, unstable carbon and stable carbon. Results: The availability of unstable carbon and stable carbon controlled by soil acidity on undisturbed peat swamp forest as a result, the accumulation of unstable carbon as well as stable carbon occurred even if the soil pH declines and vice versa. However, stable carbon associated well with soil acidity. It was found that the C/P ratio positively correlated with humic acid and stable carbon of both before and after logging conditions. Nevertheless, that association was prominent on logged peat swamp forest. An indication that even though this peat swamp forest had been logged, humification was strongly maintained. However, the similarity of stable carbon of the logged peat swamp forest with stable carbon of undisturbed peat swamp forest indicate an ineffectiveness humification of logged peat swamp forest. Conclusion: Logging operation on sensitive forest with peat soil using heavy machinery increased the bulk density because of compaction. Soil acidity has important role in preserving soil carbon storage of this natural peat swamp forest, especially stable carbon. After the peat swamp forest is logged, humification processes are strongly maintained but slows and becomes ineffective, hence unstable carbon decomposes more instead of it being preserved as stable carbon. Disturbance by logging operation does not alter their amount of soil carbon storage (stable carbon) due to the carbon in humic acid is quite stable within one year.
  Empi Rambok , Seca Gandaseca , Osumanu Haruna Ahmed and Nik Muhamad Ab. Majid
  Problem statement: Despite few studies of forest health and environmental conditions of mangrove forest in Sarawak, the data was not sufficient to facilitate baseline data and direct comparison of mangrove forest health obtained for different location of mangrove forest in Sarawak. On this regard, determination of contemporary mangrove soil condition was essential to addressing mangrove forest for forest health, carbon storage and environmental balance. The study attempts to obtained preliminary database of mangrove forest soil chemical properties and to compare the forest health from two different mangrove forest locations. Approach: Mangrove soil samples were taken from Miri and Limbang Division of Sarawak at 0-30 cm depth. Selected soil chemical properties were determined and data obtained were analyzed using Statistical Analysis System (SAS) Version 9.2. Results: The soil acidity, total N, total P, CEC and humic acid of both locations were significantly different while in terms of total carbon and organic matter were similar. Conclusion: Regional diversity has significant effects the soil acidity, total N, total P, CEC and yield of the study areas. Data obtained can be useful for further study of carbon stock and nutrient content.
 
 
 
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