Systems Approach to Efficient Field Machinery Utilization for Lowland Rice Production

Within the agricultural sector, there are wide variations in the level and pattern of energy use among various crops. To assess this energy demand, quantitative data on operating conditions is required for each unit operation. With the current increase in world population, energy consumption needs effective planning. One way to optimize energy consumption in agriculture is to determine the efficiency of methods and techniques used. This study was carried out with the ultimate aim of developing a model that could be used for estimating the energy consumption in a lowland rice production system and to predict the potential yield of rice from operational energy inputs and from quality indices of tillage and planting operations. Tillage systems obtained with factorial combinations of tractor forward speeds obtained from four transmission gear selections and three rotary tilling speeds were compared with respect to effective field capacity and energy requirements for implements used in the typical sequence for each system. The effects of the rotary tillage systems on irrigated soil properties in terms of changes in bulk density, cone index, plasticity index, aggregate uniformity coefficient and organic matter content were also investigated. Energy analysis for the entire production process included the operational energy consumption by field machinery and human labour, and the indirect energy accounted for by fertilizer, pesticides and seeds used, Functional relationships that allow the quantification of the different processes in the developed simulation model were formulated essentially through the use of secondary data and through curves fitting to some real data. Mathematical equations from agricultural machinery management and empirical equations were employed. Results from the tillage experiment indicate that differences in field capacity, and fuel and total energy requirements for each tillage system can be attributed primarily to many factors such as soil moisture, soil density, rotary tilling speed, and operation speed and depth. Average total energy inputs in the lowland rice production system (excluding irrigation energy) summed up to about 12225.97 ha-I. As main consumers of energy, fertilizer (7721 .O3 ha-'; 63.2%) and fuel use (2717.82 MJha- '; 22.2%) were identified. Human labour, pesticide, seeds and indirect energy for machinery use had marginal importance, contributing only 0.2%, 0.6%, 6.8% and 6.9%, respectively to the total energy consumption. Focusing on the operational energy consumption for the lowland rice production, the main energy use was in field cultivation activities (23 10.24 MJIha; 64.2%, planting included) and harvesting ( I 171.44 ~ J h a - '3: 2.6%). while spreading of fertilizer and pesticide had only little importance within total mechanization. Indirect energy use for mechanization took about 848.95 ha-' or 23.6% from total energy use for mechanization of 3595.87 h ha-'. Compared to total energy demand of 12225.97 h ha-I. indirect energy use for mechanization was even less important (6.9%). Average grain yield was 6470.8 kg ha-', representing energy output of 108321.75 mJha - 'that is, 96095.78 MJ net energy gain or 8.86 MJ output per MJ input. Energy input per kilogram grain yield was 1.89 M J ~ ~ -T' .h e simulation results obtained from the developed computer program regarding direct and indirect operational energy consumption in the lowland rice production were consistent with those obtained from the field study. The results of the study could serve as a guide to lowland rice farmers in other geographical locations in achieving their production goals. Improvements could be made through the application of the simulation model by figuring out the energy input requirements for all possible combinations of field operations for lowland rice production. It is suggested, as a consequence of this research, that paddy farmers in the Tanjong Karang Rice Irrigation Scheme of Malaysia and other schemes with similar operational conditions adopt the use of Gear 1 High and rotary tilling speed of 175 rpm for tillage operations. The application of this practice should reduce the excessive demand on fossil fuel energy which currently is very expensive and whose continuous availability is unpredictable. This will assist in the on-going campaign to minimize the flux of hard currency out of most developing and transition countries in the form of energy bills. The results and recommendations here are based on the available data on the current practices involved in the lowland rice production system of Malaysia and hence are useful for the current lowland rice crop planning and farm management practices

Depletion of gaseous polycyclic aromatic hydrocarbons by a forest canopy

Rapid uptake of gaseous polycyclic aromatic hydrocarbons (PAHs) by a forest canopy was observed at Borden in Southern Ontario, Canada during bud break in early spring 2003. High volume air samples were taken on 12 individual days at three different heights (44.4, 29.1, and 16.7 m) on a scaffolding tower and on the forest floor below the canopy (1.5 m). Concentrations of PAHs were positively correlated to ambient temperature, resulting from relatively warm and polluted air masses passing over the Eastern United States and Toronto prior to arriving at the sampling site. An analysis of vertical profiles and gas/particle partitioning of the PAHs showed that gaseous PAHs established a concentration gradient with height, whereas levels of particulate PAHs were relatively uniform, implying that only the uptake of gaseous PAHs by the forest canopy was sufficiently rapid to be observed. Specifically, the gaseous concentrations of intermediate PAHs, such as phenanthrene, anthracene, and pyrene, during budburst and leaf emergence were reduced within and above the canopy. When a gradient was observed, the percentage of PAHs on particles increased at the elevations experiencing a decrease in gas phase concentrations. The uptake of intermediate PAHs by the canopy also led to significant differences in gaseous PAH composition with height. These results are the most direct evidence yet of the filter effect of forest canopies for gaseous PAHs in early spring. PAH deposition fluxes and dry gaseous deposition velocities to the forest canopy were estimated from the concentration gradients

Determination of leaf area index for oil palm plantation using hemispherical photography technique

The present conventional (destructive) method used in determining LAI is laborious, difficult and time consuming. Thus, an image-based measurement using camera system with fish eye lens offers an alternative means for an accurate indirect measurement of LAI in oil palm. In this study, a methodology was developed to improve the leaf area index of the oil palm determination using hemispherical photography as an indirect method. A set of true LAI data, collected using the destructive method, were used as a reference to calibrate the LAI measurements obtained by the hemispherical photography. A good relationship (r = 0.85) was found between age of palm and hemispherical photographic LAI. However, the estimated LAI obtained by the hemispherical photographic method was underestimated as compared to the destructive method. Some means of calibration was necessary to determine the relationship between the actual LAI and the hemispherical photographic LAI. It was necessary to multiply the LAI value from 5 years to 16 years, by a clumping factor of 2.14 for 5 to 9 year old palms, 2.33 for 10 to 14-year old palms and 2.37 for above 15-year old palms to calculate the accurate LAI values. For palms which are less than 5 year old (i.e. 2 to 3 years in this study), the photography LAI value was equal to the calculated LAI value. This proposed that correction factors would solve this underestimation effect. In addition, two equations were also proposed to estimate the true LAI from the Photographic LAI for immature and mature oil palm plantation

A modified soil tilth index and its relationship with rice yield

This study was conducted to investigate the effect of rotary tillage on some soil physical properties (bulk density, cone index, plasticity index, aggregate uniformity coefficient) and organic matter, and to develop and evaluate a soil tilth index based on changes of these soil properties. The tillage treatments were 4×3 factorial combinations of forward speeds obtained with four selected tractor transmission gears (Gear 1 High, Gear 2 Low, Gear 3 Low and Gear 4 Low), and three rotary tilling speeds (140 rpm, 175 rpm and 200 rpm) of commonly used tillage implements in Malaysian paddy fields. Experimental results indicated a significant decrease in bulk density of the soil due to rotary tillage. The other soil parameters were not significantly affected by the tillage operation. Analysis of variance indicated significant difference (p<0.01) among the rice yield means. Bulk density was identified to have a high positive correlation with the rice yield. A tilth index consequently developed with bulk density, cone index and plasticity index gave better predictability (r2= 0.56) of rice yield than when individual soil properties were considered. Results of the study suggest that tilth index may assist in yield prediction by comparing measured soil conditions in a paddy field

Seroprevalence of Human Immunodeficiency and Hepatitis B Viruses among Patients at a Health Facility in Freetown, Sierra Leone

Human Immunodeficiency Virus (HIV) and Hepatitis B Virus (HBV) constitute serious public health problems worldwide. In Sierra Leone, information on both viral infections remains scanty. This study estimated the seroprevalence of HIV and HBV infections and a possible co-infection in one hundred and ninety-eight (198) patients seeking diagnosis at a private laboratory in Freetown, Sierra Leone. Blood plasma was collected from each patient after informed consent was obtained. The samples were assayed for antibodies to HIV virus and HBV antigen using appropriate assays. Male patient accounts for 52% of the population examined. Thirty-one (31) of the 198 patients examined (15.7%) were positive for HIV. Hepatitis B surface antigen (HbsAg) was present in 17 (39.5%) females and 26 (60.5%) males. Thirteen (13) (6.6%) patients were co-infected with HIV and HBsAg. This is the first documented evidence of HBsAg and HIV co-infection in Sierra Leoneans. Larger population based studies are however needed to confirm the findings. Key words: Co-infection, Hepatitis B surface antigen, HIV, Seroprevalenc

A national survey of rice (Oryza sativa L.) grain quality in Sierra Leone I: Perception of traders and consumers

As Sierra Leone approaches self-sufficiency in rice, against a backdrop of agricultural commercialization, the dynamics of the rice grain production and consumption will increasingly be driven by the quality of grains  demanded by consumers to be produced by farmers and marketed by traders in the open market. The present study was a national perception survey aimed at establishing the current status of rice grain quality based on the perspectives of traders and consumers interviewed at selected market places in four major cities across the country. In separate interviewsconducted with315 consumers and traders selected at random from 45 markets around the country, individual responses were solicited on the general interests of consumers and traders, as well as the marketing practices and aspirations for the improvement of rice grain quality in the country. Results obtained from the two surveys suggest that the priorities of rice consumers for grain quality were generally similar to those of thetraders. For example, between to 63 to 100 per cent (84 %all cities) of consumers and 69 to 100 percent (88% all cities) of traders interviewed indicated preference for imported rice, with a significant positive correlation (r = 0.78) between the two groups. Among rice products found in the market, the imported high swelling, long grain rice was shown to be preferred by both traders and consumers, due mostly to the high swelling power and non-seasonal market availability of that grain type. Other results suggest that both traders and consumers desire further improvement in grain quality, even though they do not consider this to be of high priority. The study leads to the conclusion that imported rice products are more popular than local rice products among rice traders and consumers in Sierra Leone. It is speculated that such preference might have been driven directly by the priorities of household food decisions and indirectly by the general socio-economics of food production and consumption in the country.Keywords: Rice grain quality, consumers, Sierra Leon

Knowledge, Perception of Risk and Attitude of Sierra Leone Military Personnel towards Colleagues with HIV/AIDS

The aim of this survey was to gain an insight into the level of knowledge, perception of risk and attitude of Sierra Leone Military personnel towards colleagues with HIV/AIDS. Four hundred and fifty (450) randomly selected male and female military personnel including officers and other ranks from six battalions were surveyed with a standard questionnaire. Results of this survey demonstrated a relatively low level of knowledge of HIV and AIDS amongst the survey population as evidenced by the 40% and 52% of participants stating that HIV is transmitted by mosquito bites and from public toilets respectively. An equally low perception of risk of the infection was demonstrated from the responses of the participants about attitude towards HIV infected colleagues. Three-fourth of the participants indicated that nobody should be informed if a colleague is HIV positive, with almost all the participants expressing their willingness to take care of an HIV/AIDS person in their household. Varying responses obtained demonstrate the necessity for scaling-up HIV education within the Republic of Sierra Leone Armed Forces. More resources most therefore be made available to the HIV/AIDS office of the Republic of Sierra Leone Armed Forces so that HIV education activities can be extended to all the brigades and battalions. Keywords: Knowledge, Perception, Attitude, HIV/AIDS

Treatment of Uncomplicated Falciparum Malaria with Artesunate-Amodiaquine Combination Therapy (ACT) in a Rural Fishing Community in Sierra Leone

Until recently, Chloroquine was the mainstay for malaria chemotherapy in Africa because it is cheap, safe and practicable for out-patient use. Resistance to this drug has however over the past decade, presented a major public health problem with therapeutic and prophylactic implications. As a response to the emergence of resistance to the commonly used antimalarial drugs, the World Health Organisation (WHO) now recommends the use of artemisinin-based combination therapies (ACTs). We assessed the therapeutic efficacy of oral Artesunate-Amodiaquine hydrochloride combination therapy in the treatment of uncomplicated falciparum malaria in a rural fishing community in Sierra Leone. One hundred and fourteen (114) participants aged 0 – 5 years attending the Outpatient Department of Gbondapi Health Centre were screened for recruitment into the study of which 70 fulfilled the inclusion criteria. Artesunate-Amodiaquine hydrochloride combined drug which passed the general counterfeit test of the Ministry of Health and Sanitation was used in the study. Adequate Clinical and parasitological Response (ACPR) was observed in 97% of the study population. Mean parasite clearance time in the participants with ACPR was found to be 24 hours (range 24 –72 hours). All 3% of the treatment failures were observed to be Early Treatment Failures (ETF). Results from the study indicate that Artesunate-Amodiaquine hydrochloride combination therapy is an effective antimalarial drug in a high transmission zone like Sierra Leone, and in the event that the drug is not effective, the results will be evident within one day of commencement of treatment