Guinea Savanna Agro-ecological Zone Research Articles

Characterization of Groundnut (Arachis hypogaea L.) Test Locations Using Representative Testing Environments With Farmer-Preferred Traits.

In this study, the differential rankings of 36 groundnut genotypes under varying environmental conditions were studied at various levels of phenotype. Locations that are generally accepted by the crop- and soil-based research community to represent the entire Guinea and Sudan Savanna agro-ecological zones in Ghana were characterized, this time using a crop. The characterization was done based on four farmer-preferred traits (early and late leaf spot disease ratings, and haulm and pod yields) using three models (i.e., AMMI, GGE, and Finlay–Wilkinson regression). These models were used to capture specific levels of phenotype, namely, genotype-by-environment interaction (GE), genotype main effect plus GE (G+GE), and environment and genotype main effects plus GE (E+G+GE), respectively. The effect of three major environmental covariables was also determined using factorial regression. Location main effect was found to be highly significant (p < 0.001), confirming its importance in cultivar placement. However, unlike genotypes where the best is usually adjudged through statistical ranking, locations are judged against a benchmark, particularly when phenotyping for disease severity. It was also found that the locations represent one complex mega-environment, justifying the need to test new technologies, including genotypes in all of them before they can be approved for adoption nationally. Again, depending on the phenotypic level considered, genotypic rankings may change, causing environmental groupings to change. For instance, all locations clustered to form one group in 2017 for early and late leaf spot diseases and pod yield when GE was considered, but the groupings changed when G+GE was considered for the same traits in the same year. As a result, assessing genotypic performance at the various levels to arrive at a consensus decision is suggested. Genotypes ICGV-IS 141120 and ICGV-IS 13937 were found to be the best performing.

Analysis of Environmental Factors Determining the Adoption of Land Management Practices in Guinea Savanna Agro-Ecological Zone of Kaduna Using Principal Component Analysis (PCA)

This study analyzed the various determinants of land management practices in Chikun LGA of Kaduna State and determined most sustainable practice(s), with the specific focus on: Socio-economic characteristics of farmers; types of land management practices in relation to the determinant factors; effects of land management practices on the farm productivity; determine the most sustainable land management practice in the study area. A purposive sampling technique was adopted in collecting data from three hundred and eighty (380) rural farmers with structured questionnaires administered in Buruku, Chikun Local Government area of Kaduna State, Nigeria. Five land management practices showed positive effects on the farm productivity as compared to the mean of 3 points; these were cover crop, crop rotation, irrigation, organic manure and fertilizer application. Two land management practices as perceived to have good effects on farm productivity of respondents were agro-forestry and bush fallow as shown in the component one of the result of Principal Component Analysis (PCA). It was concluded that the farming population was ageing and was adversely affected the choice of best practices due to lack of education and knowledge to adopt the best land management practice. Sustainable land management practices has the potential to reverse the trend of food scarcity and environmental disasters, help to improve local livelihoods, restore natural ecosystems and also contribute significantly to climate change adaptation and mitigation. There is clear evidence that the productivity of soils in Buruku Village will continue to decline if strategic measures are not put in place to manage soil fertility in different soil units to support agricultural land.

Some Correlation Coefficients of Maize under Soil-application of Pendimethalin in Mubi and Gombe Ecologies of Nigeria

Field experiment was carried out during the wet season of 2012 at the Teaching and Research Farm of Faculty of Agriculture, Adamawa State University, Mubi (Lat.10° 15II N and Long.13° 16II E, altitude of 696 m above sea level) and a Community based Demonstration Farm in Gombe (Lat.11° 30” N and Long.10° 20” E, altitude of 340 m above sea level). Both locations were situated in the Northern Guinea Savanna agro-ecological zone of Nigeria. The study was carried out to determine the level of correlation between weed parameters, growth and yield attributes of maize as affected by pendimethalin application. Treatments which consisted of six different rates of pendimethalin (1.0, 2.0, 3.0, 4.0, 5.0, 6.0kg a.i.ha-1) + two control checks (weed free and weedy check) were placed in the main plots as main treatment while maize cultivar SAMMAZ 17 was placed in the sub-plots as sub-treatments in a split plot design and replicated three times. Pendimethalin was pre-emergence- applied a day after sowing (DAS). Weed free check plots (control) were kept weed free by regular weeding. Similarly, all agronomic practices were adequately carried out except those under study. Data collected on weed cover score (WCS), weed fresh weight (WFW), weed dry weight (WDW), days to 50% emergence (D50E), crop injury score (CIS), crop vigour score (CVS), establishment count (EC), plant height (PH), leaf area index (LAI), crop growth rate (CGR), relative growth rate (RGR), days to 50% tasseling (D50T), 1000 grain weights (1GWTs) and grain yield (GY) were analyzed using Minitab Version 11 Statistical Software. Results revealed that WCS was significantly higher and strongly correlated with WFW, WDW but was strong and negatively associated with GY of maize in both Mubi and Gombe. D50E, D50T and LAI were positive but contributed weakly to the GY of maize in Mubi. Similarly, D50E, D50T, PH and LAI had same pattern of behavior as the former in Gombe. EC was negative and also contributed weakly to the grain yield of maize in both locations. PH, CVS, CGR, 1GWTs were positive and strongly associated with GY of maize in Mubi. The same trend was also observed for all parameters except PH which though positive it was weakly associated to the final GY of maize in Gombe. Pendimethalin did not posed any significant effect on the post- physico-chemical properties of the soils at the two experimental sites, except in soil-pH, organic carbon, available phosphorus, total nitrogen, magnesium, potassium and sodium in Mubi and available phosphorus, total nitrogen, Calcium, Magnesium and Potassium in Gombe. These soil properties were significantly influenced by rates of soil applied Pendimethalin compared to the control checks.

Stimulus of nitrogen fertilizers and soil characteristics on maize yield and nitrous oxide emission from Ferric Luvisol in the Guinea Savanna agro-ecological zone of Ghana

Abstract Farmers in Ghana rely on different forms of fertilizers to increase crop yields. The quantity of applied mineral N fertilizer is lost through nitrification and denitrification in the form of the powerful greenhouse gas nitrous oxide (N2O) has not been determined in the field until now. This study was conducted on a Ferric Luvisol in the Tolon District in Northern Ghana to determine the influence of nitrogen fertilizers, soil moisture and soil temperature on N2O emissions and grain yield. Three different nitrogenous fertilizers, i.e. ammonia sulfate (AS), urea (U) and NPK 60–40–40, were applied at either 60 or 120 kg N ha−1 yr−1 to maize, termed AS 60, AS 120, U 60, U 120 and NPK 60–40–40 thereafter. A control was left without N application. The results showed that N fertilizer type and quantities applied affected N2O emissions significantly. Plots of NPK 60–40–40, AS 60 and U 60 emitted 1.22, 1.45 and 1.79 kg N2O N ha−1, respectively, throughout the sampling period and were not considerably higher than N2O emissions from the control plots, which amounted to 0.32 kg N2O N ha−1. In contrast, the N2O emissions of U 120 and AS 120 were significantly higher than the controls, with values of 4.29 and 3.49 kg N2O N ha−1, respectively. When N2O flux was related to grain yield, 1.24 and 1.04 g N2O kg−1 grain was emitted from AS 120 and U 120, respectively. Plots treated with NPK 60–40–40, AS 60 and U 60 produced 0.39, 0.47 and 0.55 g N2O kg−1 grain, respectively, whereas plots without fertilization emitted 0.53 g N2O kg−1 grain. Average N-induced N2O emission factors ranged between 0.10% and 0.22%, with an overall emission factor of 0.15%.

Smallholder cattle farmers' breeding practices and trait preferences in a tropical Guinea savanna agro-ecological zone.

The present study was embarked upon to determine the breeding practices and choice of selection and breeding traits of cattle farmers in Nasarawa State and the Federal Capital Territory (FCT), Abuja, Nigeria. A total of 180 smallholder cattle herders were randomly sampled. However, analysis of data was restricted to 144 herders (81 from FCT and 63 from Nasarawa State). Primary data were collected through individual structured questionnaire administration. Chi-square (χ2) statistics were used to compare categorical variables. Arithmetic means of continuous variables between locations were tested using T test. Rank means were also calculated for within- and between-location comparisons of the preference traits. Chi-square automatic interaction detection (CHAID) algorithm was used to determine the influence of socio-economic parameters on the traits of preference. Access to credit, personal savings, and type of landholding were significantly (P < 0.05) different between the two locations with higher values recorded for farmers in FCT. However, farmers in Nasarawa State had significantly higher land expanse (2.28 ± 0.19 versus 1.29 ± 0.09). The production objectives were rated similar between locations. The number of foundation stock differed significantly between farmers in the two locations with higher mean recorded in Nasarawa (7.37 ± 0.37) compared to FCT (5.18 ± 0.19). However, mean herd size was higher (34.60 ± 2.58 versus 27.63 ± 2.00; P < 0.05) in FCT than Nasarawa. Among the productivity indices, only average age at first parturition and average calving interval were significantly (P < 0.05) influenced by location. Within the FCT, calving interval was the trait of utmost importance in selecting the breeding stock, followed by milk yield, disease resistance, and body size. In Nasarawa State, calving interval, disease resistance, milk yield, body size, and survival were ranked similarly (P >0.05). Across the two locations, body conformation (P < 0.05) and calving interval (P < 0.01) were more highly rated in FCT than Nasarawa State, while heat tolerance was less rated (P < 0.05) in the former. All the traits of preference were influenced by socio-economic factors, and could be exploited in future breeding plans to boost cattle production. A new livestock census in the study area is also advocated to reflect the current reality as regards cattle distribution.

Genetic Studies of Morphological and Physiological Traits Associated with Drought and Striga hermonthica (Del.) Benth Tolerance in Maize (Zea mays L.) in the Guinea Savanna Agro-ecological Zone of Ghana

Genetic Studies of Morphological and Physiological Traits Associated with Drought and Striga hermonthica (Del.) Benth Tolerance in Maize (Zea mays L.) in the Guinea Savanna Agro-ecological Zone of Ghana

Growth and yield variability of groundnut (&lt;i&gt;Arachis hypogaea&lt;/i&gt; L.) cultivars infected with cowpea aphid-borne mosaic virus disease

Groundnut ( Arachis hypogaea ) is a major legume crop with diverse uses in Nigeria. Its productivity is however threatened by Cowpea aphid-borne mosaic virus (CABMV) in most groundnut producing areas, resulting in huge losses. This study was conducted to determine the resistance of some commercial groundnut cultivars under CABMV disease. The experiment was conducted in Minna, Southern Guinea Savanna agro-ecological zone of Nigeria. Twenty groundnut cultivars were evaluated separately as healthy and CABMV infected trials. The experiment was laid out in randomised complete block design with three replications. Seedlings were infected with the virus by mechanical inoculation at 10 days after sowing. The plants were observed for disease incidence, growth and yield attributes. The data collected were subjected to analysis of variance, principal component and cluster analyses at p≤0.05. One hundred percent infection was found regardless of the cultivar. The healthy plants exhibited significantly (p<0.05) higher morphological and yield parameters than infected plants. Principal component analysis revealed that 100-seed weight accounted for the greatest variability in healthy (eigen vector = 0.6239) and CABMV infected (eigen vector = 0.6005) plants. Cluster analysis showed that 18 (90 %) cultivars formed cluster 1, whereas one cultivar each was found in cluster 2 and 3. The top three cultivars for 100-seed weight: “SAMNUT 23” (56.0 g), “SAMNUT 25” (50.5 g) and “SAMNUT 26” (50.9 g) were the most tolerant to CABMV, whereas “ICG-92267” was identified as the best cultivar for dry matter production (24.0 g/plant). Planting of these tolerant cultivars is recommended in order to mitigate the stresses imposed by CABMV. Keywords: disease incidence, principal components, clusters, groundnut

Nitrogen Use Efficiency and Maize Productivity in the Guinea Savanna Agro-ecological Zone of Ghana

Nitrogen Use Efficiency and Maize Productivity in the Guinea Savanna Agro-ecological Zone of Ghana

Response of Grain Legumes to Phosphorus Application in the Guinea Savanna Agro-Ecological Zones of Ghana.

Grain legumes (cowpea, peanut, and soybean) play important roles in household food and income security in smallholder farming systems in the Guinea Savanna agro-ecological zones of Ghana. However, yields are low, rarely exceeding 600 kg ha–1, prompting the need to evaluate responses of grain legumes to P fertilizer applications for two seasons. Conducting P studies is critical to help farmers adopt economic-based recommendations. Treatments evaluated in 2015 for the three crops were (i) farmers’ practice (no input and planted by farmer); (ii) control (no input and planted by researcher), and (iii) triple super phosphate (TSP) fertilizer. However, for soybean, an additional two treatments (inoculant only and inoculant plus TSP fertilizer) were included. In 2016, the treatments were the same, except on-farm demonstrations were not conducted on cowpea. The demonstrations were laid out in a Randomized Complete Block Design with each demonstration rep-resenting a replicate within a region. On average, P-fertilizer application increased yields by 296; 527, and 390 kg ha–1 for cowpea, peanut, and soybean grains, respectively. On average over the two seasons, P-fertilizer increased yield by 9.85; 13.00, and 17.56 per kg ha–1 kg–1 P applied for cowpea, soybean, and peanut, respectively, and these applications were cost effective. Peanut showed little response to P in the Upper East Region compared with a greater response in the Northern and Upper West Regions, suggesting that benefits from P-fertilizer for peanut may be location-specific. On average, rhizobium inoculation increased grain yield by 157 kg ha–1 across the three regions and significantly positive effects of inoculation were observed in both seasons. Our results show that substantial increases in grain legume yield may be achieved by applying P fertilizers, but farmers cannot afford them because of their relatively high cost. Planting adapted and improved varieties and using rhizobium inoculants may provide the most economically viable and low risk options for increasing yields of grain legumes in the savanna agro-ecological zones of Ghana

Uptake and Use Efficiencies of Nutrients by Sesame and Bambara Nut Alley Crops as Influenced by Manuring in a Cashew-Based Intercropping System in the Guinea Savanna Agroecology of Nigeria

Field experiments were conducted at at the experimental farm Cocoa Re-search Institute of Nigeria (CRIN) Sub-Station, Ochaja, in the Southern Guinea Savannaagro ecological zone of Nigeria to examine uptake and use efficien-cies of nutrients by Sesame and Bambara nut alley crops as influenced by manuring in a Cashew-based intercropping system. Experimental treatments were based on responses of sole and intercrop mixtures of Sesame and Bam-bara nut alley crops to Cocoa Pod Husk (CPH), pelletized organic fertilizer and NPK fertilizer in a cashew-based intercropping system. Data were collected on the growth and yield variables of the alley crops. Highest nitrogen harvest in-dex (NHI) for seed and leaf of alley crops were obtained from un-manure treated plants. Cocoa pod husk (CPH) significantly enhanced P uptake com-pared with other fertilizers applied. CPH improved Na, Ca, Mg Zn, Cu, P, K and carbohydrate in the leaves and Ca, Mg, Zn, Fe, Cu, crude fibre and car-bohydrate contents of seeds of sole crops while Sesame + Bambara had en-hanced contents of N, Ca, Mg, Zn, Cu, P, N, K, moisture, protein, and crude fi-bre, crude protein, moisture content in leaves. The effects of NPK were signifi-cant for N, K Ca, Zn, Fe, Cu, P, moisture and crude fibre, while in the un-manure (control) plots influenced N, fat and protein and nitrogen harvest index (NHI) of leaf and seeds. CPH and NPK fertilizers enhanced nutrient up-take and nitrogen harvest index of alley crops. Nutrient uptake was similar for the varieties of Sesame and Bambara nut as affected by the application of 4.84 and 9.68 Kg pelletized organic fertilizer. Sole Bambara had higher N and K concentration in leaves compared with Bambara +Sesame. In addition, sole Bambara had higher values of Physiology efficiency (PE), and fertilizer use ef-ficiency (FAE) compared to the mixed crops of Bambara + sesame. However, physiology efficiency (PE), and fertilizer use efficiency (FAE) were significantly lower for Bambara + Sesame. The un-manure plants had enhanced N, P and K uptake. Varietal effects were pronounced for most of the resource use effi-ciency variables measured. The alley crop varieties responded differently to 4.84 and 9.68 kg pelletized fertilizer treatments (Agronomy Efficiency (AE), N-removed at harvest and Internal Utilization Efficiency (IE) and partial fac-tor productivity (PFP)). Sesame variety NCRIBen04E had enhanced AE, N-remove at harvest, IE and PFP while variety E8 had significantly higher ap-parent Recovery Efficiency (RE), apparent Recovery Efficiency by difference (RE%), Physiology Efficiency (PE), Utilization Efficiency (UE), and internal Utilization Efficient (IE). Bambara variety TVSu999 had higher IUE, Agron-omy Efficiency (AE), Apparent Recovery Efficiency (RE), Physiology Effi-ciency (PE) and Fertilizer Agronomy using Efficiency respectively (FAE) com-pared to variety TVSu1166. The fertilizers affected most of the indicators of nutrient use efficiency (NUE) measured. The effects were significant on AE, agronomic N-use efficiency (ANUE), RE, UE and PFP. NPK fertilizer enhanced Physiology efficiency (PE) and Partial factor production. NPK fertilizer signifi-cantly enhanced NUE parameters compared to CPH and un-manure. CPH manure significantly influenced RE%, PE and IE. The Internal Utilization Effi-ciency and N-remove at harvest were compared with the un-manure plants (control). The effects of 9.68 kg/plot pelletized fertilizer, were pronounced on Agronomy Efficiency (AE), Apparent Recovery Efficiency by difference (RE%), Physiology Efficiency (PE), Utilization Efficiency (UE), N-removed at harvest and Internal Utilization Efficiency (IE). Similar trends were observed in the responses NUE of Sesame and Bambara manuring. The responses sole crops in terms of RE, PE UE PFP were similar while their intercrop combina-tions had significantly higher AE, RE, UE, PFP and N removed at harvest. Sole Sesame significantly influence Agronomy Efficiency (AE), Utilization Effi-ciency (UE), Internal Efficiency (IE) and Partial Fertilizer Production (PFP) and sole Bambara under NPK fertilizer had enhanced N-removed at harvest and apparent recovery by difference (RE%). Bambara + Sesame under cocoa pod husk (CPH) manure had enhanced apparent recovery efficiency by difference (RE%), fertilizer use efficiency (FAE) and internal utilization efficiency (IE). Sesame variety NCRIBen04E had enhanced Agronomy Efficiency (AE), N-removed at harvest and Internal Utilization Efficiency (IE) under 9.68 kg treatment while variety E8 had higher partial factor productivity (PFP) at 4.84 kg/plot pelletized organic fertilizer.

Serum Biochemistry Reference Intervals of &lt;i&gt;Clarias gariepinus&lt;/i&gt; Farmed in Earthen Pond Systems in the Southern Guinea Savanna Agro-Ecological Zone of Nigeria

The monitoring of health in fish farms partly relies on the availability of exact serum biochemistry reference intervals as these data provides a base for the interpretation of tests to assess health status. Serum biochemistry reference intervals for Clarias gariepinus cultured in earthen pond system was established following evaluations of two hundred and forty healthy fish sampled across eight farms. The S.B.R.I were: Total protein 31.22-42.11 g/dl in juveniles and 38.96-43.57 g/dl in adults; Albumin 6.72-10.21 g/dl in juveniles and 6.25-8.93 g/dl in adults; Globulin 8.39-50.83 in juveniles and 24.23-33.64 g/dl in adults; Alanine aminotransferase 12.55-23.65 IU/L in juveniles and 7.35-13.72 IU/L in adults; Aspartate aminotransferase 90.62-121.64 IU/L in juveniles and 83.41-101.62 IU/L in adults; Glucose 17.04-26.22 mg/dl in juveniles and 10.17-48.93 mg/dl in adults; Cholesterol 91.09-101.24 mg/dl in juveniles and 91.40-155.87 mg/dl in adults; HDL-cholesterol 9.17-29.01 mg/dl in juveniles and 19.27-29.01 mg/dl in adults. Other results include Lactate dehydrogenase 28.06-54.03 mg/dl in juveniles and Urea 1.96-4.11 mg/dl in juvenile fish. These data will serve as a tool for the monitoring of health and nutritional condition of Clarias gariepinus farmed in ponds at the Southern Guinea Savanna agro-ecological zone of Nigeria.

N2-fixation and N contribution by grain legumes under different soil fertility status and cropping systems in the Guinea savanna of northern Ghana

Continuous cereal-based cropping has led to a rapid decline in soil fertility in the Guinea savanna agro-ecological zone of northern Ghana with corresponding low crop yields. We evaluated the effects of cropping system and soil fertility status on grain yields and N2-fixation by grain legumes and net N contribution to soil fertility improvement in contrasting sites in this agro-ecological zone. Maize was intercropped with cowpea, soybean and groundnut within a row, with a maize stand alternated with two equally spaced cowpea or groundnut stands and in the maize-soybean system, four equally spaced soybean stands. These intercrops were compared with sole crops of maize, cowpea, soybean and groundnut in fertile and poorly fertile fields at sites in the southern (SGS) and the northern (NGS) Guinea savanna. The proportion of N derived from N2-fixation (%Ndfa) was comparable between intercrops and sole crops. However, the amount of N2-fixed was significantly larger in sole crops due to a greater biomass accumulation. Legumes in poorly fertile fields had significantly smaller shoot δ15N enrichment (−2.8 to +0.7‰) and a larger %Ndfa (55–94%) than those in fertile fields (−0.8 to +2.2‰; 23–85%). The N2-fixed however was larger in fertile fields (16–145kgNha−1) than in poorly fertile fields (15–123kgNha−1) due to greater shoot dry matter and N yields. The legumes grown in the NGS obtained more of their N requirements from atmospheric N2-fixation (73–88%) than legumes grown in the SGS (41–69%). The partial soil N balance (inkgha−1) was comparable between intercrops (−14 to 21) and sole legumes (−8 to 23) but smaller than that of sole maize receiving N fertiliser (+7 to +34). With other N inputs (aerial deposition) and outputs (leaching and gaseous losses) unaccounted for, there is uncertainty surrounding the actual amount of soil N balances of the cropping systems, indicating that partial N balances are not reliable indicators of the sustainability of cropping systems. Nevertheless, the systems with legumes seem more attractive due to several non-N benefits. Our results suggest that soybean could be targeted in the SGS and cowpea in the NGS for greater productivity while groundnut is suited to both environments. Grain legumes grown in poorly fertile fields contributed more net N to the soil but growing legumes in fertile fields seems more lucrative due to greater grain and stover yields and non-N benefits.

Nodulation and Biomass Yield Response of Cowpea to Row Spacing and Phosphorus Fertilizer Application in the Guinea Savanna Agro-Ecological Zone of Ghana

Phosphorus fertilizer application and planting distance play a major role in the production of shoot, root and nodule dry biomass of cowpea. However, phosphorus is a major limiting nutrient in soils in Ghana. Selection of cowpea varieties that produce good biomass yield under low soil phosphorus or those with high phosphorus response efficiency can be a low input approach in solving this problem in Ghana. Two-season experiments were conducted to evaluate the influence of phosphorus (P) fertilizer and row spacing on growth, nodulation and biomass yield in cowpea. Each of the two experiments comprised of 16 treatment combinations of 4 cowpea varieties, 2 levels of row spacing and 2 levels of P 2 O 5 application laid out in a 4t2t2 factorial experiments in RCBD with four replications. The cowpea varieties were IT t P 148, Valenga, Bengkpla and DPC. The levels of row spacing were 60t20 cm and 40t20 cm, whilst the levels of P were 0 and 30 kg ha -1 P 2 O 5 . The study revealed that varieties DPC and Valenga performed relatively better with respect to shoot and root dry biomass production, number of nodules produced and nodule dry biomass production across both levels of row spacing and phosphorus fertilizer application. The study further established that row spacing of 60t40 cm and P level of 30 kg ha -1 also produced significantly higher quantities of shoot and root dry biomass, number of nodules and nodule dry biomass as compared to row spacing of 40t20 cm and P level of 0 kg ha -1 . For the purpose of producing leguminous fodder crops for feeding livestock, varieties DPC and Valenga should be cultivated for improved animal nutrition. Row spacing of 60t40 cm and phosphorus fertilizer application level of 30 kg ha -1 should also be used for increased biomass yield.

Response of Jew’s Mallow (Corchorus olitorius L.) to Organic Manures in the Southern Guinea Savanna Agroecological Zone of Nigeria

Response of Jew’s Mallow (Corchorus olitorius L.) to Organic Manures in the Southern Guinea Savanna Agroecological Zone of Nigeria

English

Inoculation of promiscuous soybean with rhizobia has been proven to improve yield. Screenhouse pot experiments were conducted to assess the response of promiscuous soybean, TGx1448-2E to rhizobia inoculation and to determine the relative efficiency of indigenous rhizobia from soils collected from the Northern and Southern Guinea and Sudan Savanna agro-ecological zones of Nigeria. Soils were collected at 0 to 20 cm depth from 45 sites spread in 15 local government areas of Kaduna and Kano states. The treatments used were uninoculated control, mineral nitrogen and Legumefix, a commercial rhizobia inoculant which were arranged in randomized complete block design and replicated three times. Nodulation and biomass were assessed at eight weeks after planting. Response to inoculation and relative efficiency were also determined. The results showed that response to inoculation was higher in the Sudan Savanna than in the Northern Guinea Savanna. These were observed in 12 out of 21 and 9 out of 19 sites in the Sudan Savanna and Northern Guinea Savanna, respectively. Of these, inoculation response reached 62 and 90% in two sites in the Sudan Savanna while it barely reached 20% in the remaining sites. The results also showed a relative efficiency which is greater than 100% in some locations. This implies that the indigenous rhizobia populations were superior to mineral nitrogen and Legumefix inoculant. Notable among the locations were ALB 1, GRK 1, SOB 4 and KOL, which spread across all the agro-ecological zones. Strains from such locations have high potential for use as inoculants. Key words: Legumefix, mineral nitrogen, inoculation, indigenous strains, agro-ecological zones.

English

Good strategies for water conservation, runoff or flood control and erosion management can be achieved by proper understanding of soil water infiltration characteristics. Three infiltration models Kostiakov&rsquo;s (1932), Philip&rsquo;s (1957) and Horton&rsquo;s (1940) were used to evaluate the infiltration characteristics of soils in a long-term fertilizer experiment in the Northern Guinea Savanna Agro Ecological zone with regard to the effects of long term land use and soil management. A double ring infiltrometer was used to conduct infiltration measurement on ten plots having different combination of Dung (D), Nitrogen (N), Phosphorus (P), and Potassium (K) fertilizer treatments. Thus, the treatments combinations were DNPK, DN, DK, DP, D, NPK, N, P, K and CT (no fertilization). Soils were predominantly sandy loam and bulk density and organic carbon were significantly influenced by the fertilizer combinations. Linear least sum of squares was used to obtain the model fitting parameters. Measured infiltration rates for plots that received dung (singly or in combination with mineral fertilizer) were significantly higher (p&lt;0.05) than for the CT plots. Kostiakov&rsquo;s and Philip models showed good agreement with measured infiltration due to large R2 (0.9956 and 0.986) recorded, respectively except Horton&rsquo;s model, which gave low regression coefficient between measured and calculated data. Based on R2 values obtained from comparing measured and calculated cumulative infiltration, Kostiakov&rsquo;s and then Philip&rsquo;s equations provided best predictions over Horton. Fitting parameters obtained are suggested for use of site-specific or management-specific solutions of infiltration-related application. Further work is required to obtain reliable fitting parameters for Horton&rsquo;s infiltration equation of the trial field. &nbsp; Key words: Kostiakov, Philip, Horton, infiltration characteristics, DNPK plots.

Measurement and Modeling Nitrous Oxide Emissions from Ferric Luvisols in the Guinea Savanna Agro-ecological Zone of Ghana

Agricultural sector in Ghana contributes to about 60% of Gross Domestic Product (GDP) and is mainly characterized by fertilizer application to improve depleting soil fertility. With the increase in population and demand for increased productivity, application of inorganic fertilizers will result in enhanced greenhouse gas emissions. As nitrogen (N) is among the most limiting soil nutrient in the Guinea Savanna, chemical/organic fertilizers are applied in significant amounts to maintain crop productivity. Because of increased fertilizer and manure application to replenish dwindling soil fertility, the region is likely to become a significant source of nitrous oxide (N 2O) emissions. To study the effect of fertilizer application on N 2O emissions, Denitrification decomposition model (DNDC), a process-base model of carbon (C) and nitrogen (N) biogeochemistry in agricultural ecosystems was calibrated with field data obtained in 2013 and was used to predict the impact of N fertilizer source and rate of application on N 2O emissions. The linear equation between measured and modeled annual fluxes from ferric luvisols showed a

Carbon Dioxide Emission from Ferric Luvisols: The Role of Mineral Nitrogen Fertilizers and Soil Temperature in the Guinea Savanna Agro-ecological Zone of Ghana

Authors' contributions This work was carried out in collaboration between both authors. Author WKA wrote the protocol, designed the study, managed the analyses of the study and performed the statistical analysis and wrote the first draft of the manuscript. Author PKK reviewed the experimental design and all drafts of the manuscript and approved. Both authors read and approved the final manuscript. ABSTRACT Soils in the Guinea Savanna Agro-ecological zone of Ghana are inherently low in fertility, especially nitrogen. Furthermore, organic matter is very low as a result of total removal of crop residue followed by animal grazing and annual phenomenal bush burning. This has led to a reduction in soil carbon content and poor soil C:N ratio. With increase crop production, soils are amended with mineral fertilizer in most cases. In order to improve the soil carbon stocks and determine its losses in the soil, many studies have been conducted on the use of both inorganic and organic fertilizers as soil amendments and their impact on soil carbon partitioning. However, in the Guinea Savanna Agro-ecological zone of Ghana, there is paucity of information on the effects of mineral fertilizers on soil carbon emissions. Also, there are few reports of CO 2 flux from soils in the Guinea Savanna

Fertilizer and Genotype Effects on Maize Production on Two Soils in the Northern Region of Ghana

Soils in the Guinea Savanna agro-ecological zone of Ghana are depleted in major nutrients by continuous cropping and residue removal, resulting in low maize yields. While many studies have assessed the fertilizer requirements for maize, most did not account for the role of the soil type and maize genotype. A study was conducted on Plinthosol and Lixisol in the Tolon district of the Northern Region of Ghana to assess fertilizer and genotype effects on maize productivity. Two maize genotypes (i.e. Obatanpa -110 days to maturity) and (Dodzie - 75 days to maturity) were compared at three fertilizer application rates (i.e. 0-0-0, 60-15-35 and 90-25-50 kg ha&lt;sup&gt;-1&lt;/sup&gt; N, P K) in a randomized complete block design using four replications, with genotype allocated to the main plots and fertilizer levels to the subplots. Soils were characterized, revealing very low total N and available P concentrations in the top layers. Grain yield was significantly affected by maize genotype, irrespective of the soil type. The longer-duration (Obatanpa) tended to out yield the short duration genotype (Dodzie), and generally outperformed Dodzie in all yield parameters except for the harvest index on Plinthosol. Inorganic fertilizers significantly (P&amp;lt;0.001) increased yield and all yield parameters over the control on both soils, with yield increases of 84 and 90% at 60-15-35 and 90-25-50 kg ha&lt;sup&gt;-1&lt;/sup&gt; N, P K, respectively. Genotype by fertilizer interaction was highly significant (P&amp;lt;0.001) for grain yield on both soils. We conclude that farmers in the Guinea Savannah agro-ecological zone of Ghana need to supply nutrients to enhance grain yields of maize, irrespective of the prevailing soil type.

Variations in Stem Borer Infestation and Damage in Three Maize (&amp;lt;i&amp;gt;Zea mays&amp;lt;/i&amp;gt; L.) Types in Southern Guinea Savanna and Rainforest Zones of Nigeria

The effects of location, maize types and borer control with carbofuran (Furadan 3G®) on the severity of maize stem borer infestation and damage was investigated in the late maize planting season of 2011. Treatments were laid out in randomized complete block design using a split-slip-plot factorial arrangement. Whole plot factor consisted of two locations (Southern Guinea Savanna and Rainforest agro-ecological zones of Nigeria), subplot factor consisted of 1.5 kg a.i.ha-1 and 0.0 kg a.i.ha-1 of carbofuran, while the sub-sub-plot factor comprised of three endosperm types of maize (flint, pop and sweet corn). Stem borer infestation (quantified by dead heart count and larval population per plant) and damage (quantified by %lodged stem, %bored internodes, %bored ears, number of exit holes, number of stem borer cavities and number of damaged seeds per plant) as well as yield were compared. Results revealed that borer infestation and damage were significantly higher (P 0.05) location × carbofuran × maize type and location × maize type effect was detected. However, significant (P < 0.05) location × carbofuran and carbofuran × maize type interaction effects were observed. We conclude that in both agro ecologies, flint corn was more tolerant of borer attack while sweet corn was more susceptible compared to either flint or popcorn. In addition, carbofuran at 1.5 kg a.i.ha-1 can significantly reduce stem borer population in the three maize types.