Agriculture

The presence of heavy metal residues in food products is a potential hazard to humans and animals as these metals cannot be degraded and stay permanently in the environment hence there is a need to ascertain the safety of these products for human consumption. The concentration of heavy metal residues in meat, milk and cheese were assessed in three locations in Ondo State. A total number of 120 animals (comprising 30 cows and 90 bulls) and 30 cheese samples were sampled for the investigation. The samples were digested with concentrated nitric acid and the resulting solutions were analyzed using Atomic Absorption Spectrophotometer (AAS) for lead, copper, zinc, cadmium and chromium. The result revealed that the concentration of each metal was significantly (P < 0.05) different due to the location. The results were compared with Maximum Recommended Limit (MRL) as set by FAO. The cadmium concentration in the kidney samples obtained from Owo has a mean concentration level of 1.23mg/kg, which is above those collected from Ondo (0.53mg/kg). However, Cadmium was not detected in kidney samples from Akure. Chromium concentration was high in kidney samples from Ondo and Owo with values of 1.11 and 1.21mg/kg respectively than those recorded in Akure (0.31mg/kg). The mean level of copper in skeletal muscle from Akure (3.17kg/kg) was higher when compared with the 2 other locations (Ondo 1.48mg/kg; Owo 1.82mg/kg). The mean concentration of lead in skeletal muscle (2.09mg/kg) and kidney samples (0.89mg/kg) were significantly higher than liver samples (0.78mg/kg). Of these skeletal muscle, kidney and liver samples, 100%, 46.7%, 73.3% exceeded the MRL by FAO respectively. For cadmium, the result showed that kidney samples of slaughtered cattle contained a mean value of 0.59mg/kg. Also, the concentration of zinc in skeletal muscle and liver of slaughtered cattle were 37.65and 50.55mg/kg out of which 36.7% and 43.3% exceeded the MRL by FAO for skeletal muscle and liver respectively. The mean concentration of chromium is higher in kidney samples (0.88mg/kg) than skeletal muscle (0.77mg/kg and liver (0.83mg/kg). Of these skeletal muscle, kidney and liver samples, 16.7%, 36.7%, 20% exceeded the MRL as set by FAO respectively. Copper mean concentration was higher in liver samples (20.57mg/kg) of which 100% of liver samples exceeded MRL by FAO. 

Experiment was set up in 2013 at the experimental field of Savannah Agriculture Research Institute to evaluate the effect of split nitrogen application on growth and yield of lowland rice. It was made up of ten treatments laid out in split plot design with three replications. Treatments were made up of two low land rice varieties (Jasmine and Degang) randomly assigned to main plots and five levels of N fertilization (control, 60 kg NPK/ha, 60 kg NPK/ha + 30 kg N/ha, 60 kg NPK/ha + 15 + 15 kg N/ha and 60 kg NPK/ha +10 + 10 + 10 kg N/ha) randomly assigned to sub plots. Fertilizers used were NPK (15-15-15) and Sulfan (24% nitrogen). Variety x split N fertilization had no significant (P>0.05) effect on all parameters measured. Main effect of variety and split N fertilization significantly (P<0.05) affected most parameters measured, especially grain yield. Jasmine proved superior to Degang in grain yield. Application of 60 kg NPK/ha + 30 N/ha optimized rice growth and maximized yield similar to 60 kg NPK/ha + 15 kg N/ha + 15 kg N/ha and 60 kg NPK/ha + 10 kg N/ha + 10 kg N /ha + 10 kg N/ha. Application of 60 kg NPK/ha + 30 N/ha is recommended for increase rice yield and income of farmers, as split application at 15 + 15 kg N/ha and 10 + 10 + 10 kg N/ha attract additional labour cost.

An experimental study was conducted under dryland conditions to determine the influence of conventional and conservation tillage systems as well as seed rate on grain yield and yield components of a wheat cultivar in the central region of Iran. The experimental design was a randomized complete block with three tillage and four seed rate treatments with three replications. Tillage treatments comprised of conventional tillage (CT: moldboard+disk), reduced tillage (RT: chisel plow+disk), and no-till (NT: direct drilling with plow no-till drill), while the seed rate treatments were 80, 100, 120, and 140 kgha^-1. Average grain yield was 1804, 1754 and 1789 kgha^-1 for CT, RT and NT, respectively. The highest wheat yield was obtained from CT and NT treatments with seed rate of 100 kgha^-1 and the lowest yield was obtained in RT treatment with seed rate of 80 kgha^-1. The trend of wheat yield with seed rate (number of plants per hectare) was approximately similar to the parabolic response curve of grain yield versus number of plants per unit area which increases quickly to a maximum and slowly decreases at higher plant densities. To achieve the maximum yield of dryland wheat in central region of Iran, applying no-till system with seed rate of 100 kgha^-1 was recommended.

Until quite recently, human urine has been tagged a ‘waste’, especially in Africa, even though the eastern, and western worlds have for centuries reaped the immense blessings associated with this “liquid gold”. It is in the light of this that this paper discusses the research work conducted to ascertain the fertilizer value of human urine and its utilization in agriculture in Kumasi, Ghana. The study investigated the maximum storage time of human urine that would result in increased NPK for crop use under green house conditions using maize as the test crop. Some morphological characteristics; number of leaves, leave length, plant height and leave width were measured. Perceptions of farmers and consumers on urine use in agriculture were also examined. In a randomized complete block design, fresh urine (0), 1, 2, 3, 4, 5, and 6 months’ old urine and NPK 15:15:15 chemical fertilizers were applied to maize crops in a green house. Prior to planting and application of plant nutrients, soil and human urine NPK contents were analysed using standard methods. Fresh urine produced the highest Nitrogen, Phosphorus and Potassium contents of 884.572mg/L, 68.044mg/L, and 180.763mg/L respectively compared to the six months old urine which yielded 700.450mg/L, 0.578mg/L and 0.096mg/L of Nitrogen, Phosphorus and Potassium contents respectively. The amounts of NPK in urine decreased with storage duration. Percentage decrease of urine NPK over the six months of storage were 20.8%, 31% and 22% respectively. Fertilization of maize crops with urine, produced crops with morphological characteristics comparable to plants fertilized with NPK mineral fertilizer – 15:15:15. Farmers, though unaware of the fertilizer value of human urine, were willing to use it in farming. Consumers however were unwilling to patronize vegetables fertilized with human urine.

Most organic vegetable farmers in Central Luzon apply the required amount of organic fertilizers only once during planting. Hence, nutrient requirement of vegetables during vegetative or reproductive stages are no longer available. This condition seriously affects the growth and development of vegetables and subsequently affecting the yield performance that may result to low yield. In order to reduce the effect of nutrient deficiency on organic vegetable production particularly on green pepper, the research aimed to: a) establish frequency of organic fertilizer application employing split application; and b) determine the yield performance and net return based on the different treatments used. The research was conducted for two consecutive dry seasons (2014 and 2015) under full organic system. Twice application of the recommended rate of organic fertilizer obtained the highest yield of 4.21 t/ha while thrice application of the recommended rate of organic fertilizer obtained the second highest with 4.14 t/ha. Basal application obtained the lowest yield of 3.89 t/ha during the first trial. Second trial of the study showed that comparable yield was obtained by twice application and thrice application with 5.03 t/ha and 5.02 t/ha, respectively. Basal application consistently produced the lowest yield. Cost and return analysis of 1000 m2 green pepper following the different treatments evaluated showed that the highest net income during the first trial was obtained from twice application of the recommended rate of organic fertilizer with PhP7,740.00 net income with an ROE of 85.05% which was lower than the ROE of the basal application with 89.76%. Lower net income was obtained from basal application of organic fertilizer due to lower yield obtained. Second trial showed that the highest net income was obtained from two split application of the recommended rate of organic fertilizer with PhP11,020.00 registering an ROE of 121.09%, the highest among the three treatments evaluated.

Pot culture experiment was conducted to study the impact of organic and inorganic phosphorus source on major and micronutrient availability for main and residual crop. Organic and inorganic Phosphorus sources (farmyard manure, poultry manure, vermicompost, sewage sludge and single superphosphate), to supply 34 kg P2O5 ha-1, were used as treatments with no phosphorus source as control. These six treatments replicated four times, making a total of 24 pots. In main groundnut crop all the phosphorus sources improved soil organic carbon and major and micronutrient contents. Among them poultry manure had the greatest influence on the availability of phosphorus, nitrogen, potassium and sulphur. In the residual sunflower crop phosphorus source improved the nutrient availability and soil organic carbon content. Among them, poultry manure registered higher soil available nitrogen and phosphorus content and sewage sludge treatment increased potassium and sulphur content. Residual iron, zinc and copper content was higher and comparable in sewage sludge and farmyard manure treatment. And residual manganese content was higher in single super phosphate treatment.

In determining meat yield and sensory attributes of 12 weeks old guinea keets, ninety guinea fowl keets (Numida meleagris) at one-week old and of equal weights were fed conventional diet based on maize, sesame and groundnut meals (210.4 gkg-1 crude protein and 11.95 mJKg-1 ME) up to 12 weeks of age, then their meat parts yield, skin colour measurements and sensory characteristics were determined. The dressing percentage gave a mean value of 68.28, while the mean carcass parts yield showed he highest relative weights for the breast (28.1) followed by the back and neck (27.9), drum sticks and thighs (27.54) and the lowest for the wings (14.86). Hunter guinea fowl’s skin colour measurements showed higher values, coinciding with the observed dark dressed carcass skin colour. Sensory properties scores for the tasted attributes showed that guinea meat have slightly desirable colour, moderately desirable flavor with moderate juiciness and tenderness.

In recent times, among of the major problems in oil palm plantations is the lack of proper interpretation of yield maps for site-specific management. The ability to determine and diagnose leaf factors that influencing yield variability of oil palm will benefits in managing the plantation for better yield. A study on spatial variability of N, P, K, Mg and Ca in oil palm leaf was carried out at the Dusun Durian Estate of Golden Hope Plantations Berhad in Selangor, Malaysia. The aim of this study is to obtain accurate and timely information on the spatial distribution and status of N, P, K, Mg and Ca in leaf using semivariogram analysis and geographical information system (GIS), and its correlation to oil palm fresh fruit bunch (FFB) yield. The collection of leaf tissue data was conducted using systematic sampling. A GPS device (AgGPS Trimble) was used to precisely determine samples locations. Geostatistics software and classical statistics were used for data analysis. Correlation analysis was used to determine the strength of the relationship between nutrient content in leaf tissue and FFB yield. From kriged map, results indicate that about 32.2% of the area is low in yield, 51.6% is moderate and 16.2% is high in yield, respectively. Correlation analyses shown the total of N and available of P in the leaf have strong positive relationship (r2 = 0.84 and 0.83) with FFB yields. Thus, result implies that N and P in leaf tissue can be used to determine the FFB yields for oil palm production.

Life is a journey. The way time flies. Three decades of academics, research and charity packed life. From 1984 – 2014 the pedestal has been on to shape tropical agriculture, capture temperate agriculture, and serve humanity in all spheres of life. Most rewarding is the metamorphosis in academics and charity at local and cross-country levels. There can be no better tribute to my lecturers, supervisors, students, bosses, schools, colleges and universities than to review this personal three decades of experimentation in tropical Nigeria.

The size and aggregation state of soil can be influenced by different soil management processes. The objective of this work was to determine the influence of three tillage practices; Manual clearing (MC), Plough tillage (PT) and Conventional tillage (CT) with vetiver grass strips (VGS) spaced at surface interval of 0 m (control), 5 m and 10 m. Soil samples were collected at (0-0.05 m) depth after each growing seasons in 2004 to 2006. Soil organic carbon was determined in the laboratory. Water stable aggregates (WSA) and mean weight diameter (MWD) were determined by wet sieving in 2004 to 2006. Soil organic carbon was significantly higher by 3.7 and 4.8%, respectively on both PH and CT than MC in 2005. Mean weight diameter was significantly increased on 10 m VGS than the control by 3.5% but similar to 5 m VGS. The result showed that tillage both (MC and PT) significantly increased water stable aggregate only in 2004 growing season by 20 and 16%, respectively. Appreciable but not significant increases in mean of WSA over the three years were 1 and 2.7% on 5 m and 10 m , respectively. The study showed that tillage and vetiver grass strips may have immediate and subsequent effects on soil aggregation.