Guinea Savanna Research Articles

Effect of nitrogen and weeding regimes on yield and yield components of maize (Zea mays L.) in the derived guinea savanna Agro-ecological zone of Nigeria

Effect of nitrogen and weeding regimes on yield and yield components of maize (Zea mays L.) in the derived guinea savanna Agro-ecological zone of Nigeria

Effect of nitrogen and weeding regimes on yield and yield components of maize (Zea mays L.) in the derived guinea savanna Agro-ecological zone of Nigeria

In the 2017 and 2018 wet seasons, field trials were conducted at the Teaching and Research Farm of the Faculty of Agriculture, Kogi State University, Anyigba to determine the effect of nitrogen and weeding regime (period of weed interference) on the yield and yield components of maize. The experimental design used was a split-plot in a randomized complete block design replicated three times. The main plot was assigned to four different levels of nitrogen 0, 40, 80 and 120 kg N/ha while the sub-plot was assigned to different frequencies or regimes of weed control. The results obtained from the study revealed that the application of 120 kg N/ha produced the highest cob weight, 100-seed weight and grain yield per hectare in both years. The study also showed that all the rates of nitrogen application resulted into increased grain yield in comparison to where there was no nitrogen application. Maize plant kept weed-free for 9 and 12 weeks after planting (WAP) and those weed infested for 3 WAP produced cob dry weight, 100-seed weight and grain yield (kg/ha) comparable to those kept weed-free throughout. From the two-year study conducted, it was found out that keeping the field weed-free for only 3WAP did not provide a satisfactory weed control situation for optimum crop performance owing to imminent re-infestation. Conversely, plants weed infested for 3WAP could ward off whatever damage that might have been inflicted initially through subsequent re-growth which could translate into impressive yield as observed in this study.

Optimum Stand Density of Tropical Maize Varieties: An On-farm Evaluation of Grain Yield Responses in the Nigerian Savanna

Selection of appropriate sowing density is an important yield enhancing management decision in maize (Zea mays L.) production particularly in rainfed conditions. This study aimed at evaluating the optimum stand densities (OSDs) of 10 recently released maize varieties under different crop management decisions and environments. Ten maize varieties of varying characteristics were planted in the Northern Guinea Savanna of Nigeria across 30 farmer's fields in the rainy seasons of 2016 and 2017 under three stand densities: 2.6, 5.3, and 6.6 plants m−2. Grain yield and yield components were greatest under the high density in both years across all locations. The intermediate maturing varieties produced higher grain yields compared to the early and late maturing varieties in both years and locations. The environmental indices from the Factor Analytic Model showed 20% of the fields were optimal, 28.3% moderate, 31.7% poor, and 20% were very poor environments. Increasing planting density did not significantly affect the grain yield of the varieties in very poor environments. A linear increase in grain yield was observed in moderate and optimum environments with every increase in stand density for all varieties except Sammaz 32, however, optimum planting densities could not be reached for all the varieties. Therefore, tropical maize varieties should be planted under specific densities that account for environmental and management conditions to maximize yield.

Ticks and prevalence of tick-borne pathogens from domestic animals in Ghana

BackgroundTicks are important vectors of various pathogenic protozoa, bacteria and viruses that cause serious and life-threatening illnesses in humans and animals worldwide. Estimating tick-borne pathogen prevalence in tick populations is necessary to delineate how geographical differences, environmental variability and host factors influence pathogen prevalence and transmission. This study identified ticks and tick-borne pathogens in samples collected from June 2016 to December 2017 at seven sites within the Coastal, Sudan and Guinea savanna ecological zones of Ghana.MethodsA total of 2016 ticks were collected from domestic animals including cattle, goats and dogs. Ticks were morphologically identified and analysed for pathogens such as Crimean-Congo haemorrhagic fever virus (CCHFV), Alkhurma haemorrhagic fever virus (AHFV), Rickettsia spp. and Coxiella burnetii using polymerase chain reaction assays (PCR) and sequence analysis.ResultsSeven species were identified, with Amblyomma variegatum (60%) most frequently found, followed by Rhipicephalus sanguineus sensu lato (21%), Rhipicephalus spp. (9%), Hyalomma truncatum (6%), Hyalomma rufipes (3%), Rhipicephalus evertsi (1%) and Rhipicephalus (Boophilus) sp. (0.1%). Out of 912 pools of ticks tested, Rickettsia spp. and Coxiella burnetii DNA was found in 45.6% and 16.7% of pools, respectively, whereas no CCHFV or AHFV RNA were detected. Co-infection of bacterial DNA was identified in 9.6% of tick pools, with no statistical difference among the ecozones studied.ConclusionsBased on these data, humans and animals in these ecological zones are likely at the highest risk of exposure to rickettsiosis, since ticks infected with Rickettsia spp. displayed the highest rates of infection and co-infection with C. burnetii, compared to other tick-borne pathogens in Ghana.Graphical

Genetic analysis and yield assessment of maize hybrids under low and optimal nitrogen environments

Development of maize hybrids that possess tolerant genes to low soil nitrogen is critical for long-term maize production in areas with low soil fertility. In this study, estimates for combining ability effects for grain yield and secondary traits of selected inbred lines, identify potential parents for hybrid development and yield potential of the crosses under sub-optimal and optimal N environments. One hundred hybrids were evaluated under sub-optimal and optimal N environments for two years. The experimental layout was a 10 × 10 alpha lattice design with two replications for two experiments. The results obtained showed that, the genotypes evaluated varied for grain yield and the characters measured under sub-optimal and optimal N conditions. Grain yield reduction due to N stress was 40.9%. General and specific combining ability (GCA) and (SCA) effects for mean squares varied for grain yield demonstrating the importance of additive and non-additive genetic effects for the hybrids evaluated under the study conditions. Even though significant variations were detected for GCA and SCA, GCA which is the additive gene action component mainly controlled the heritage of grain yield under both conditions. Inbred line 15 was identified as the superior parent with positive and significant GCA for grain yield under sub-optimal N. Genotypic correlation studies displayed that grain yield was positively correlated with ears per plant under sub-optimal N and was also positively associated with anthesis-silking interval under high N. The hybrids 52, 75, 81 and 37 were identified to be significantly superior in terms of grain yield, ASI and EPP under the two-contrasting conditions. The results suggest that, there is a need for development of low N tolerant inbred lines and hybrids for production under soils with low N status in the Guinea savanna of Ghana for high grain yield to be realised.

Synergistic effects of liming and balanced fertilization on maize productivity in acid soils of the Guinea Savanna agroecological zone of Northern Ghana

Soil acidity and very low nutrient status are major production-limiting factors for maize production in most parts of the savanna agroecological zones (AEZ) of northern Ghana. Therefore, effective nutrient management is critical to increase productivity. During a two-year study across six locations in the Guinea Savanna AEZ in northern Ghana, we evaluated the interactive effects of liming and balanced fertilization on maize productivity in acid soils. Six fertilization strategies – (i) balanced (containing all essential limiting nutrients), (ii) balanced with sulfur omitted (minus-S), (iii) balanced with zinc omitted (minus-Zn), (iv) balanced with boron omitted (minus-B), (v) NPK-only, and (vi) control (no nutrients supplied) – were evaluated, each with or without liming. Applying only lime without fertilizer application increased maize yield from an average of ∼0.55 t ha − 1 to ∼0.92 t ha − 1. For NPK-only fertilization, liming led to an increase in yield from an average of ∼1.68 t ha − 1 to ∼2.84 t ha − 1. For balanced fertilization, lime application resulted in an additional maize grain yield of ∼53% compared to treatment without lime application. With liming, the minus-Zn treatment resulted in a significant yield decrease of an average of ∼30% compared to balanced fertilization, suggesting that combined application of lime and Zn should be advocated to better sustain crop productivity in this region. We conclude that, to improve maize productivity in acid soils in order to ensure increased profitability and improved household income, fertilizer recommendations that promote balanced fertilization must include liming as part of the nutrient application package.

Speargrass [Imperata cylindrica (L.) Raeuschel] Growth in Relation to Season, Rainfall and Temperature Patterns of Southern Agro-ecologies of Nigeria

Speargrass posed a major constraint to crop producion in some agroecologies in Nigeria. Hence, the study was conducted to investigate the influence of seasons, rainfall and temperature patterns on speargrass components growth with the view to improve its management. This study was conducted between 2014 and 2016 at Eruwa (7˚32’0˚N, 3˚ 25’0 ˚E, 187m altitude) in Derived savanna (DS) and Kishi (08˚.98’N, 003˚.94’E; 364m altitude) in the southern Guinea savanna (SGS)–northern fringe agroecologies of Nigeria. Twelve months of the year starting from July were randomly assigned to plots in an abandoned speargrass infested farmland, replicated three times and arranged in Randomized Complete Block Design. Monthly temperature, rainfall and speargrass samples (shoot and rhizome) were measured. Results showed that rainfall amount varied across the months in both locations. The highest rainfall was recorded in September (264.20 mm) and hottest month was May, 2016 (28.5oC) in Derived savanna between 2014 and 2016 (Table 1). Kishi had 186 mm rainfall in the wettest months and the hottest months had 28.0 oC within the specified period of the study (Table 2). Total speargrass total dry weight (STDW) increased with rise in rainfall in both locations. Meanwhile, there were variations in the components (Shoot and rhizome) weight. However, there was decline in speargrass dry matter during the dry months (January to April) in the locations. This might have reflected the effects of moisture deficit. Notwisthanding, Rhizome:shoot varied at both locations. Derived savanna (Eruwa) had rhizome:shoot >1.00 in five months throughout the study (5/24), while southern Guinea savanna (Kishi) had rhizome:shoot >1.00 in eleven months (11/24). Speargrass control might be more challenging especially in SGS than DS in the months with higher Rhizome:shoot ratio > 1.00. Derived savanna had more months (19/24 months) with lower rhizome:shoot ratio (< 1.00) than SGS (13/24 months). This might have resulted from more rainy months and better distribution of rainfall in Derived savanna for speargrass shoot growth and the resultant decrease in rhizome:shoot (< 1.00). This is a clue for better translocation of herbicides for season-long speargrass control.

Effect of Intra-Row Spacing on the Incidence and Severity of Viral Diseases of Soybean (Glycine max (L.) Merr.) in Mokwa, Nigeria

The study was conducted to assess the effect of intra-row spacing on the incidence and severity of viral disease on soybean during the wet cropping season in 2019 at the National Cereal Research Institute (NCRI), Mokwa field, located in the Southern Guinea savanna of Nigeria at an altitude of about 212 metres above sea level. Observation and data collection were done on the disease incidence and severity rating; also, plant height, the number of leaves, the number of pods per plant, the number of seeds per pod and Grain yield (t/ha) were determined at harvest. Data collected on growth and yield parameters were subjected to analysis of variance (ANOVA) using the general linear model (PROC GLM) procedure of SAS (2008). The means of significant (p≤0.05) F-test were separated using the Least Significant Difference (LSD) at a 5% probability level. The Elisa results obtained revealed the presence of Cowpea mottle virus, Cowpea yellow mosaic virus and Soybean mosaic virus. Also, the field trial showed that the different spacing and soybean cultivars investigated differ significantly on the variables tested. However, optimum spacing at 20 cm and 1448 - 2E had significantly (P<0.05) increased in all vegetative, reproductive growth and yield as well as reduced incidence of the soybean viruses detected in the field. From the above results, spacing at 20 cm with the cultivation of soybean cultivar 1448 - 2E and appropriate cultural practices are hereby recommended to farmers in the area.

Response of Maize-Hybrids Phenology Under high Plant Population Density in parts of Northern Guinea Savanna of Nigeria

Plant distribution in the field, as affected by plant density, has been one area that has received a great deal of attention over the last several decades. Population density, whether directly on the plant or indirectly on biotic factors associated with plant density is one of the most important factors in determining physiological attributes of a crop. Maize grain yield has a parabolic response to stand density that maximizes yield, which is widely known by the crop managers, physiologists and breeders; together with the concept that this optimum stand density varies with the environment. Development of breeding populations and hybrids with improved tolerance to high plant densities should be an important part of maize breeding programs. A field experiment was therefore conducted during 2015 and 2016 rainy season at Tudun Wada, Kano and Shika, Zaria in the Northern Guinea savanna of Nigeria in order to assess the phenological components of maize-hybrids at high plant population density. The experiment consisted of two plant populations of 53,333 plantha-1 and 88,888 plantsha-1 as main plot and eight recently developed drought–tolerant maize hybrids: M0826-7, M0926-8, M1026-10, M1026-13, M1124-4, M1124-10, M1227-12 and M1227-14 and two widely cultivated commercial hybrids as controls (Oba-98 and Oba super-1) as sub-plots laid out in a randomized split-plot design and replicated three times. Maize-hybrids responded to high plant population density in the two locations. Increasing plant population significantly decreased the phenology of maize-hybrids, which showed better adaptation of hybrids to high plant population density. Hybrids showed shorter days to maturity and shorter anthesis-silking interval. Maize-hybrids performed better at Zaria than at Tudun Wada because rainfall was higher and better distributed in this location. However recent hybrids were more tolerant to high plant population than the commercial hybrids, therefore the recently released maize-hybrids were more adapted to biotic stress.
 Keywords: Biotic stress, Growth, Phenology, Plant population density and Maize-hybrids

Afforestation of Transformed Savanna and Resulting Land Cover Change: A Case Study of Zaria (Nigeria)

This paper presents the effects of actions aiming at tree planting, and thus protection of the land belonging to Ahmadu Bello University (ABU) in Zaria (Nigeria) from erosion. This area is located within the northern limits of the Guinea savanna belt, which has been considerably transformed primarily for agricultural purposes. For years this area has been subjected to the destructive surface and gully erosion processes, which were documented both by field work and the analysis of high-resolution images presented by Google Earth. Land erosion leads to the silting of an impounding reservoir (Kubanni)—the primary water source for the university campus and the basis for its existence. Since 2000, the university has been actively involved in tree-planting efforts in the campus vicinity, executed mainly through the establishment of small plantations ranging in area from approximately 1 ha to 56 ha. Today, these measures have brought tangible effects such as increment of tree-planted expanses, as evidenced in the multitemporal analysis of the Landsat 7 ETM+ and Landsat 8 OLI satellite images. The increasing planted area protects both the soil and the reservoir. A marked stand increment (almost doubled) has been recorded, which is evident from the satellite imageries, and is presented on the land-use map produced with GIS technique for this project.

Response of Maize (Zea mays L.) Varieties to Nitrogen Application in the Guinea Savanna Agro-Ecology of Ghana

Response of Maize (Zea mays L.) Varieties to Nitrogen Application in the Guinea Savanna Agro-Ecology of Ghana

Managing essential plant nutrients to improve maize productivity in the savanna agroecological zones of Northern Ghana: the role of secondary and micronutrients

Studies have shown that despite the positive response of maize to nitrogen (N), phosphorus (P), and potassium (K), actual yields in the savanna agroecological zones (AEZs) of northern Ghana remain well below the potential even with N-P-K fertilizer application. In a two-year nutrient omission trial in 12 locations within the Sudan savanna and Guinea savanna AEZs of northern Ghana, we quantified maize yield increases resulting from addition of secondary and micronutrients from the NPK-only fertilization practice for maize production in the two AEZs. In both years, applying only NPK fertilizer resulted in average yields of 3.6 t ha − 1 and 2.5 t ha − 1 in the Guinea savanna and Sudan savanna AEZs, respectively. However, addition of sulfur (S), zinc (Zn), and boron (B) to the NPK fertilizers (“balanced” fertilization) resulted in an average of 60% and 64% yield increases over those of the NPK-only treatment in the Sudan savanna and Guinea savanna AEZs, respectively. Compared to balanced fertilization, omission of S, Zn, and B reduced grain yield by an average of ∼34%, ∼28%, and ∼14%, respectively. The combined data suggest that, even though secondary- and micronutrients are needed in small quantities by plants relative to N, P, and K, they have an enormous effect on crop productivity. Therefore, to ensure sustainably increased maize productivity in the savanna agroecological zones of northern Ghana, fertilizer recommendations should not be restricted to only NPK fertilizers but all limiting secondary- and micronutrients must be accounted for in a holistic and balanced fertilizer recommendation.

Soil suitability evaluation for maize in Lere local government area of Kaduna State Nigeria

The soils of Lere (Saminaka) in Kaduna state, Northern Guinea Savanna climatic zone was evaluated for suitability of maize (Zea mays) cultivation, employing various methods. Data were obtained through field study and laboratory analyses. Three soil Units were delineated, and one profile was sunk in each of the soil units. The profiles were described according to USDA soil survey manual, and soil samples were collected from each pedogenetic horizon, stored in nylon bag properly levelled. The soil samples were processed and analyzed using standard laboratory procedures. The soil Units were designated as SM1, SM2, and SM3. The textural class of the surface soils are sandy loam to loam. The result shows that soils pH is strongly to moderately acidic (5.5 – 5.8); soil fertility was generally low with evidence of low organic carbon (0.59 – 0.66%), total nitrogen (0.35 – 0.70%) and CEC (4.1 – 5.3 cmolkg-1), while potassium (0.12 – 0.31 cmolkg-1) and phosphorus (12.6 – 25.3 mg kg-1 ). The results also showed that climate, topography (slope), soil depth, and texture and fertility are optimum for maize production, with drainage and base saturation as the major limiting factors, with the aggregate of not-suitable (Nfw) in all the soil units based simple limitation method. By employing other methods (Storie and Khiddir square root), the same results were obtained, with little improvement in the Square root method (Rabiah) as the classes change from N or N1 to S3. Incorporating soils with organic materials and encouraging subsurface drainage will improve maize production.

Evaluation of furrow infiltration by Swartzendruber and Horton’s models in Northern Guinea savanna of Nigeria

The study aimed at evaluating two models (Swartzendruber and Horton) using furrow infiltration data measured in Samaru, Zaria. These measurements were carried out on the three field plots A, B and C. Infiltration parameters were generated from the data measured from plot A and B and fitted into the models for predictions of water infiltrated depths at different time intervals. The predictions from the models were compared with the measured field data from plot C. Statistical indices such as coefficient of determination (R2), root mean square error (RMSE) and T-test at 5% level of significance were used to determine the best performing model. The results show that, value of R2 and RMSE recorded for Horton’s model was 0.996 and 3.05, while the value of R2 and RMSE recorded for Swartzendruber’s model was 0.998 and 3.01, respectively. The T-test values obtained for Horton’s model was 2.93, while 2.51 was recorded for Swartzendruber’s model. The results of the evaluation indicated that both models were considered suitable because they presented high values of R2 and low values of RMSE as suggested by Aminu (2019). Similarly, the results obtained from the T-test statistics indicated that there is a no significant difference between the models evaluated because the calculated values of ‘T’ 2.93 and 2.51were greater than the tabulated value 2.365 at 5% confidence interval. Therefore, this study recommends that both models should be used to predict infiltration rates of soils in the study area.

EFFECT OF FOUR BIOCHAR TYPES AND INORGANIC PHOSPHATE FERTILIZER ON GROWTH AND NODULATION OF SOYBEAN (GLYCINE MAX (L.) MOENCH)

There is a compelling need to explore the use of biochar as a sustainable alternative to the use of chemical or mineral fertilizer amendment in the contexts of soybean cropping system in Sub-Sahara Africa. A pot experiment was conducted to evaluate the effects of poultry manure biochar (PB), swine dung biochar (DB), maize cob biochar (MB), saw dust biochar (SB) and inorganic phosphate fertilizer (single supper phosphate) applied singly on the growth and nodulation of soybean in Minna, southern Guinea savanna zone of Nigeria. The biochars were applied at four levels of 0, 5, 10, and 15 t ha-1 while single supper phosphate (SSP) was applied at 30 kg P ha-1. The experimental design was a completely randomized design (CRD) with three replications. The results showed that soybean plant parameters of height, number of leaves, number and dry weight of nodules, shoot, root and total dry biomass increased in all treatments that received animal waste biochars (PB & DB) over the non-treated control (0 t ha-1) except the plant root length and shoot/root ratio. However, the difference was statistically significant (p<0.05) only at the higher application level of 10 t ha-1. Plant-based biochars (MB & SB) were less beneficial to soybean plant, and their influence on soybean parameters did not differ significantly from non-treated control. Soybean plant also responded positively to the application of SSP but was significantly better than the control only for plant height. The results showed that animal waste-derived biochars were more beneficial to soybean plant in terms of nodulation and growth than the plant-based biochars and SSP fertilizer. Evidence that soyabean growth, biomass accumulation and nodulation benefit more from amending soil medium planted to soyabean with manure based biochars applied at 10 tons ha-1 compared to the plant-based biochar showed that, manure base biochars are more suitable as soil amendments for legumes like soyabean that require more P and less amount of N in their nutrition.

Ecology of Aedes vittatus (Diptera: Culicidae) in rock pools across agroecosystem in Northern Savanna, Nigeria.

This study focuses on modulating dexterity of some ecological variables of Aedes vittatus classically breeding in rocky habitats. The study provides a useful insight into ecological variables that underpin or hinder profuse breeding of Ae. vittatus in rock pools and its probable role in disease transmission. HANNA HI98129 pH/EC/TDS/TEMP meter was used in situ while standard protocols were used to determine other hydro-chemical variables. Aedes vittatus larvae were obtained with soup ladle and modified ladle dippers. D-frame net was used to capture macroinvertebrates while plankton net was used to obtain samples of microalgae. Tadpoles and water turtles were collected with fine mesh invertebrate net. Macrophytes were uprooted and identified at the Herbarium Unit, Department of Botany, Ahmadu Bello University, Zaria. The influence of physicochemical variables was correlated with distribution of Ae. vittatus using Principal Component Analysis. Regression and ANOVA were used to test for association between predictor variables and mosquito abundance and for the difference amongst inselbergs. Linear larval density of Ae. vittatus in rock pools which tapered across Guinea savanna were obtained from twenty-one sites with average density of 139.6 in Sudan savanna. Guinea savanna had an average larval density of 75.5 with lower subsets of moving average densities compared to Sudan savanna. One hundred and sixty-one aquatic insects belonging to four insect orders cohabited rock pools with Ae. vittatus. Toads and frogs' tadpoles were of Bufonidae and Pyxicephalidae families while water turtles belong to Emydidae. pH, TDS (ppm), EC (μs/cm) and alkalinity (mg/l) differed significantly (p<0.05) with the abundance of Ae. vittatus in rock pools. Temperature, depth, water hardness and total suspended solid had direct influence on the distribution of Ae. vittatus in rock pools across sites. Significant positive correlation exists between aquatic insects and abundance of Ae. vittatus. Hydroperiod length, concentration of nitrate and pH were determinants that leverage profuse breeding of Ae. vittatus and survival of rock pool biota. Results revealed that the bearing influence of rock pool variables is inevitable for breeding of Ae. vittatus. A well defined measure of efficacy incorporating indigenous communities for sustained vector control on inselbergs will go a long way in decimating population of Ae. vittatus and limit the risk of spread of yellow fever hitherto areas not thriving.

MICRONUTRIENT DYNAMICS IN RELATION TO SOIL PROPERTIES IN ARABLE SOILS OF RIGACHIKUN-KADUNA, NORTHERN GUINEA SAVANNAH, NIGERIA

The research was conducted within January 2020 – January 2021 at the arable soils of Rigachikun-Kaduna, Northern Guinea Savanna and intended to study the micronutrient dynamics and relationships with some studied soil properties. Previously harvested maize, cowpea and rice soils (designated as Locations A, B and C respectively) were delineated, and three profile pits dug in each along the line of transect of about 100 m apart. A total of nine profile pits were dug in the three delineations and samples collected from each pit according to their horizonations. The use of Digital Elevation Model (DEM) was employed to study the terrain characteristics of the location. Major micronutrients investigated were Cu, Fe, Zn and Mn. Virtually all micronutrients decreased down the profile in all studied locations with Cu and Zn displaying an irregular trend in all pedons of rice harvested soils in location C. Also Fe rather increased in pedon 1 of location C as well. Cu had positive and non-significant correlation with other micronutrients (Fe and Zn), it however had a significant relationship with Mn. With respect to other soil properties investigated, Cu maintained a negative non-significant correlations. Fe had a positive and highly significant correlation with Mn and Zn. Also, Fe had a significant and negative correlation with organic matter but positive with available phosphorus. Fe was positively but non-significantly correlated with other soil properties such as clay, Ca, Mg, and total exchangeable bases (TEB). There was however, a non-significant and negative correlations of Fe with soil pH, K, Na as well as total exchangeable acidity (TEA). Mn only had significant and positive correlations with all other micronutrients (Cu, Fe and Zn) but non-significantly correlated with other soil properties. Micronutrients were all low to a deficiency level considering their critical limits in the tropical soils. Low organic matter content of soils of Rigachikun may have contributed to low micronutrient reserve of the soils. Activities that will conserve organic matter such as accumulation of litter from harvested crops and alternative means of cattle rearing such ranching rather than freelance grazing should be employed, as efforts to replenish micronutrients through fertilization has not yielded the desired results.

Effect of Landuse on Floristic Composition and Diversity of Medicinal Plants in the Guinea Savanna Zone of Ghana

Effect of Landuse on Floristic Composition and Diversity of Medicinal Plants in the Guinea Savanna Zone of Ghana

Evaluation Of Signal Strength And Quality Of A Ku-Band Satellite Downlink During Raining Season In Guinea Savanna Region Of Nigeria

This study presents the evaluation of signal strength and quality of a ku-band satellite downlink signals during raining season in Guinea Savanna region of Nigeria. Rain rate data and ku-band signal over Jos were retrieved from the Nigeria Meteorological Agency (NIMET). Rain rate data was measured using Davis Vantage Vue weather station while microwave signal were obtained using spectrum analyzer. The measured data were analyzed using Microsoft office excel. Rainfall is broadly classified into two types: stratiform (drizzle: ≤5mm/hr and widespread: &gt;5≤25mm/hr) and convection (shower: &gt;25≤50mm/hr and thunderstorm: &gt;50mm/hr). Results were calculated based on ITU-Recommendations P.618-12 and P.838. The results obtained revealed that the effect of rain on signal strength and quality on a ku-band link depend on the rain type and duration of rainfall. The effect of drizzle (≤5mm/hr) on the ku-band link is not significant regardless the duration of rainfall. The results also shows that severe signal losses above 60dB were obtained under shower (&gt;25≤50mm/hr) and thunderstorm (&gt;50mm/hr). Also, widespread (&gt;5≤25mm/hr) that prevailed for a longer period causes severe signal losses. This is to say that lower rain rate of about 25mm/hr that prevailed for a very long time have significant effect on Kuband link. The results of this study will serve as crucial design parameters for communication systems engineers for providing fade margins and developing accurate fade mitigation techniques (FMTs) for the Guinea Savanna region of Nigeria. It was observed from this study that the experimental studies within the Ku-band frequency are getting over exhausted. Therefore, experimental studied in the region of higher band like K and Ka are highly recommended.

Prediction of infiltration rates of fallow and cultivated soils in Minna, Southern Guinea Savanna zone of Nigeria

Measurement and modelling of soil water infiltration under field condition are crucial to management of water resources, design and execution of drainage and irrigation projects for sustainable agricultural productivity and food security. This study was carried out to determine the time required to attain equilibrium or final infiltration rate of soils of Gidan-Kwano (a sandy loam) and Shintako (a loamy sand) sites around Minna, and reduce the tedium, time and cost associated with the measurement of soil infiltration rate. Three infiltration models (Kostiakov, Horton and Philip models) were evaluated. A double-ring infiltrometer was used to measure the infiltration rates of the soils at the two sites subjected to two land use management practices (fallow and cultivated soils) in Minna, Southern Guinea savanna zone of Nigeria. Infiltration runs were conducted at 0, 4, 8 and 12 weeks after cultivation. Results showed that the equilibrium infiltration rate of the tested soils was attained between 1 and 2 hours. The equilibrium infiltration rates of the fallow and cultivated soils were 21.54 and 7.62 cm hr-1, respectively, at the Gidankwano site, while the values at the Shintako site were 30.59 and 24.50 cm hr-1, respectively for the fallow and cultivated soils. Generally, the soils under fallow exhibited higher infiltration rates than cultivated ones. Curvefitting was done on Kostiakov’s, Horton’s and Philip’s infiltration models. Infiltration data generated using Kostiakov’s model were not significantly different from field-measured values at 5 % level of probability. The Kostiakov model was the most suitable for the prediction of infiltration rates of the soils investigated compared to Philip and Horton models. It is therefore, recommended for the soils tested, in the Southern Guinea savanna zone of Nigeria.