Savanna Agro-ecological Zone Research Articles

Effects of Biochar and Bradyrhizobium Inoculation on Nodulation, Growth, and Grain Yield of Soybean in the Guinea Savanna Agroecological Zone of Ghana

ABSTRACT Soybeans are a vital crop globally, significantly contributing to food security, soil fertility, and economic development. However, soil conditions can constrain their productivity, including nutrient deficiencies and acidity. This study explores the combined effects of biochar (BC) and Rhizobium inoculation (RI) on soybean growth, nodulation, and yield. The experiment was conducted over two growing seasons and employed a split-plot design with five BC application rates (0, 2, 4, 6, and 8 t ha− 1) and two RI levels (uninoculated and inoculated) across four replications. The results demonstrated that the integration of BC and RI significantly improved various growth parameters, including nodulation, biomass accumulation, pod number, and grain yield. The highest grain yield was observed at 8 t ha−1 BC with RI, yielding 3394 kg ha−1 in 2021 and 2542 kg ha−1 in 2022. This was identical to the yield attained with the 6 t ha−1 BC rate paired with RI in both years. The inoculated control treatment consistently demonstrated the lowest grain yield. Additionally, it showed a significant (p < .05) impact on the weight of one hundred seeds. The study also revealed significant and consistent relationships among soybeans’ growth and yield features. In conclusion, the findings suggest that the combined application of BC and RI has a positive impact on soybean yield and its key components.

Evaluating the Response of Watermelon (Citrullus lanatus (L.) to Organic and Inorganic Fertilization in Makurdi, Southern Guinea Savannah, Nigeria

Watermelon consumption in Nigeria is on the increase due to increasing awareness of its nutritional value while its production is on the decrease due to inefficiency of resource management (inputs like fertilizers). This study aims to optimize watermelon (Citrullus lanatus L.) production through the use of organic and inorganic fertilizers. The field experiment was conducted at the Teaching and Research Farm of Joseph Sarwuan Tarka University, Makurdi in the 2019 cropping season under rain-fed conditions. The site falls within the Latitude 7°4'1N and Longitude 8°3'7E at an elevation of about 97m above sea level in the Southern Guinea Savanna Agro-ecological Zone of Nigeria. The experiment treatments, namely and they were T1 (Control 0kg/ha), T2 (150 kg/ha Compost), T3 (200 kg/ha Compost), T4 (250 kg/ha Compost) and T5 (300 kg/ha NPK 20:10:10) laid out in Randomized Complete Block Design with three replications. The study revealed that in comparison with control treatments, 300 kg/ha NPK 20:10:10 produced (31.04t/ha) fruit yield, the application of 250 kg/ha compost enhanced growth and yield parameters of watermelon with fruit yield of (17.65t/ha). The research findings suggest that using compost manure at the rate of 250 kg/ha for watermelon production is viable since it is economical and environmentally friendly alternative to NPK fertilizer due to it cheap and easy to prepare methods, its beneficial effects on soil, groundwater and the environment. It is further recommended that, in Makurdi, smallholder farmers, should adopt the application of compost at the rate of 250 kg/ha for optimum yield

Quantitative analysis of soil degradation in response to land use change in the Guinea savanna zone of Ghana

Soil degradation (SD) poses a significant challenge to tropical agricultural production systems due to its role in depleting soil nutrients. Recently, SD has threatened population growth by causing hunger and poverty among smallholder farmers in the Guinea savanna agro-ecological zone of Ghana. However, SD cannot be directly measured. Instead, assessment and modelling efforts rely on biological and physico-chemical indicators. This study sought to: (i) select a minimum dataset (MDS) using a multivariate statistical technique; (ii) identify SD processes, and evaluate the extent of degradation; and (iii) suggest strategies to monitor SD in the study area. Soil samples were collected using the Land Degradation Surveillance Framework (LDSF), specifically designed for sub-plot level (1000 m2) sampling. This scheme aligns well with the typical farm structure of smallholder farmers (<10 acres). Soil samples, taken from a depth of 0–20 cm, were analyzed to assess their physico-chemical properties. Principal component analysis (PCA) identified seven key SD processes: soil texture, pH, organic carbon (OC), total nitrogen (TN), available phosphorus (Av. P), base saturation (BS) and Effective Cation Exchange Capacity (ECEC). These identified processes lead to the loss of OC, deterioration of soil texture, reduction in soil nutrients, and increased soil acidity. There was a strong positive correlation (r = 0.70, p<0.05) between soil physical and chemical properties. PC1 explained 26.86% of the total variance, followed by PC2 at 15.31%, PC3 at 12.46%, and PC4 at 9.98%. Also, PC5, PC6, and PC7 accounted for 8.49%, 7.25% and 1.42% of the variance, respectively. The land-use systems we identified significantly affected the concentration of soil nutrients (p<0.001). In our computed Composite Soil Degradation Index (CSDI), CEC emerged as the most significant SD indicator with a weight of 0.328, followed by Si:CL ratio at 0.187. The results indicate that soil management activities should focus on increasing organic matter. Soil nutrient depletion primarily occurs through several processes. Land clearing and burning of organic materials during land preparation are primary causes. Furthermore, a total crop removal during harvest, inadequate manure application, and subsequent leaching and erosion aggravates SD, leading to nutrient-depleted soils. We conclude that the loss of nutrients, specifically CEC, OC, Ex. K and Av. P is the primary contributor to chemical SD. Therefore, implementing integrated soil fertility management (ISFM) strategies, such as applying organic (e.g., animal-based manures, green manure, crop residues, compost) and inorganic fertilizers (e.g., NPK + micronutrients) is crucial for increasing soil nutrient availability, enhancing SOM content, and promoting carbon sequestration in these farming systems. This study establishes a baseline for comparing and evaluating the effectiveness of land management interventions at the landscape level in northern Ghana. Consequently, soil nutrient management should be tailored to site-specific conditions, focusing on increasing the efficiency of N, P, K and micronutrient uptake by plants. Adopting such site-specific management strategies could significantly contribute to the sustainable intensification of agricultural production systems in the Guinea Savanna agro-ecological zone of Ghana.

Effect of Lambda-cyhalothrin + Carbofuran Application and Habitat Modification on Population Dynamics Of 0rseolia oryzivora (Diptera: Cecidomyiidae) in Relation to its Parasitoids On Rice

ABSTRACT This experiment was carried out between 2018 and 2019 at the experimental site of National Cereals Research Institute’s identified hot spot (Edozhigi) for Africa rice gall midge (0rseolia oryzivora) infestation in Nigeria. Edozhigi in Niger State is within the southern Guinea savanna agro-ecological zone at latitude 09°45' N, longitude 06°07' E, to test integrated inluence of habitat manipulation, lambda-cyhalothrin and carbofuran on population dynamics of 0. oryzivora in relation to its parasitoids on rice. The treatments were arranged in split-plot and laid out in a RCBD with three replicates. Data were collected on number of tiller / stand, plant height, days to 50 percent flowering, percent incidence, percent severity, percentage parasitism of 0. oryzivora, panicle per meter square, grains per panicle and yield of rice. Data collected were subjected to Analysis of Variance and significant means were separated using Student Newman Keuls Test, (SNK) at 5 % probability. The result showed that Rice plots treated with P. scrubiculatum + 0.38L/ha lambda-cyhalotrin +3.75kg/ha carbofuran had lower incidence (2.36) and severity (1.54) of 0. oryzivora compared with incidence (7.99) and severity (7.40) respectively found in untreated plots (control). It also had significantly higher yield (3263.95kg/ha) compared with the yield (2688.28kg/ha) in control plots. In conclusion, having P. scrobiculatum at boarder of net plots enhanced number of parasitoids and reduced attack of rice by 0. oryzivora. Integration of habitat modification with insecticide application offers better protection of rice against O. oryzivora. Key words: Habitat P. scrobiculatum, Infestation, Modification, Galls.

Assessment of Weathering Intensity and Pedogenesis of Lithosequence Located in Two Agroecological Zones of Nigeria

Elemental oxides can help to identify processes of soil formation and the degree of soil development. This study assessed soil development and weathering intensity in soils developed on schist and older granite in upland tropical rain forest and southern guinea savanna agro ecological zones of Nigeria. Soil profile samples were collected in each of the study locations. In the laboratory, total elemental oxides was determined using the energy dispersing X-ray Fluorescence (EDXRF) XRF SPEC (Minipal 4). The relative intensity of weathering of total elemental oxides was determined by choosing titanium as the suitable indexing element and the relative gain or loss of element was estimated using relative retained element (Ro) equation. Result obtained, revealed that SiO2 was the most abundant in the soils. Distribution of Al2O3 and CaO showed the direction of the pedogenic age. Older granite soil had higher values of Al2O3 and lower values of CaO. There was negative relationship of SiO2 with Al2O3 and Fe2O3. The trace elemental oxides were less than 1% and zirconium oxide was the most retained oxide in the soils. Soil which developed on schist retained more of the trace elements than soil on older granite. There was evidence of alitization, ferritization and desillication in the soils. Parent materials contributed to loss and gain of trace elemental oxides. Older granite soil was more weathered and pedologically older than schist derived soils.

Effects of urea-treated rumen digesta pellet concentrate on digestibility, growth performance and blood profile of Djallonké sheep

Rumen digesta is a waste product from the abattoir and slaughterhouse. In most developing countries, it discarded in a manner that causes pollution in the environment. It contains partially fermented feedstuff with a CP ranging from 9 to 20%. Addition of urea and pelleting of feed has been proven to further enhance the nutrient quality and digestibility of the feed. The study sought to evaluate the effects of dried rumen digesta pellets (DRDP) concentrate on intake, apparent digestibility, growth performance and blood profile of Djallonké sheep in the savanna agro ecological zone of Ghana. Four levels of DRD (0%, 5%, 10% and 15%) were incorporated into a concentrate diet and fed to sixteen (16) Djallonké rams with mean initial weight of 9.± 0.37 kg. The four concentrates were pelleted and fed with rice straw as the basal diet and replicated four times in a completely randomized design (CRD) for 84-d. The CP content of the concentrate was in the range of 101.0 to 131.4 g/kg DM. The NDF and ADF were in the range of 447.6 to 543.9 and 235.0 to 198.7 respectively. Dry mater intake did not differ amongst the rams. However, crude protein intake was significantly higher in rams fed 15% DRD. Whereas DM digestibility coefficient did not differ, a significant difference was recorded in the CP digestibility coefficient of rams with the highest obtained in rams fed 10 and 15% DRD. Final live weight gain was significantly different with rams fed 15% DRD recording twice the gain in rams fed the control diet. The trend was similar for the average daily weight gain with rams on 15% DRD recording a significantly higher gain compared to the control (48.93 vs 28.89 g/day/head). Haematological parameters of rams after the feeding trial were not significantly affected (p<0.05) by the dietary treatments. The serological parameters measured for all the rams fed the DRD concentrate did not differ (p>0.05) among the dietary treatments except albumin and Blood Urea Nitrogen concentration which were significantly influenced (p<0.005) by dietary treatment. Feeding young rams with DRDP improved the final live weight gain and average daily weight gain of Djallonké rams in the Savanna agro ecological zones and could therefore be used as a supplement for small ruminants.

Quality of seed lots of soybean [Glycine max (L.) Merrill] genotypes produced in a guinea savanna agroecology of Ghana

Crop yield is a derivative of the number of plants harvested. In Ghana, soybean fields are mostly sparsely populated with less than the optimum number of plants, a phenomenon that contributes to poor yields of only 46% of the crop’s potential in farmers’ fields. The low plant population could be the result of the poor quality of the seed planted. Meanwhile, the quality of seed is determined by crop production practices, the environmental conditions of the mother plant, and postharvest handling technologies used. Over 90% of the country’s soybean seed comes from the northern part of Ghana, predominantly the Guinea Savannah. In this study, seed lots of soybean genotypes produced within the Savanna Agroecological Zone of Ghana, were evaluated for physical and physiological traits, and the prevalence of seed borne fungi. Results showed that seed lots produced within the zone and stored under ambient conditions have medium-sized (100 to 140 g/1000 seeds) seeds with an average seed weight of 133 g/1000 seeds. The seed lots evaluated had physical purity values higher than the minimum certification standard of 98% for soybean seed in Ghana. Wrinkled seeds were the most dominant component of the seed with visual defects followed closely by seeds that were discoloured, cracked, and those with purple stains. Aspergillus flavus, Aspergillus niger, Chaetomium globosum, Rhizopus sp and Macrophomina phaseolina were the main fungi identified. Furthermore, the seed lots had an average germination percentage of 86%, which is within the acceptable minimum certification standards for soybean seed in Ghana. Though germination and vigour were variable among the seed lots tested, these parameters were not affected by the presence of the fungi species identified and the amount of seed with visual defects. The findings of this study strongly suggest that the low plant density and the resultant poor yields of soybean usually recorded in farmers’ fields in Ghana are likely due to suboptimal seeding rates at planting coupled with the low use of good agronomic practices with only a small fraction attributable to poor seed quality. Key words: Soybean, Ghana, fungi, savanna agroecology, viability, vigour, shrivelled seeds, germination

Assessment of the impact of crop management strategies on the yield of early-maturing maize varieties in the drylands of Niger Republic: Application of the DSSAT-CERES-Maize model

Maize is increasingly becoming important in Niger for use as food and feed. Production is however, faced with several abiotic and biotic constraints. Researchers have developed early-maturing maize varieties that are tolerant to drought, the parasitic weed Striga hermonthica and diseases that fit into the short growing production environment. The evaluation and deployment of these varieties would, however, involve costly and time-consuming field trials across the maize production zones of the country. The CERES-Maize model was applied to assess the performance of two early-maturing maize varieties under varying planting windows and nitrogen application in three agroecological zones of the country. The model was calibrated with datasets collected from field trials conducted under optimal conditions (supplementary irrigation and full nutrient supply) at three locations in northern Nigeria. The model was validated with independent data set obtained from field trials conducted in 2020 and 2021 at 4 locations in the Republic of Niger under rainfed conditions. For each variety the treatments were five nitrogen (N) rates (0, 30, 60, 90 and 120 kg ha−1). The results from model calibration and validation revealed that the model accurately reproduced the observed value for days to flowering, physiological maturity, aboveground dry biomass and grain yield with low nRMSE (0.4–12.7%) and high d-index (0.70–0.99) for both varieties. The long-term simulation results (1985–2020) showed that the maize performance was dependent on location, planting window and nitrogen rates. The variety 2014 TZE-Y yielded higher than Brico in all locations for all treatments because it takes longer to mature and accumulate higher dry matter and have higher number of kernels. Simulated yields were generally higher in the Sudan savanna agroecological zone than in the other zones because of higher rainfall and higher clay content of the soil in this zone. The response to N application was influenced by planting window in each agroecological zone. With the exception of two sites, grain yield declined with planting beyond July 14 (PW3) and response to N was not significant beyond this date in the Sudan savanna agroecological zone. Grain yield declined with planting beyond July 7 in the Sahel and Sudan Sahel agroecological zones. There was no further response to N beyond 30 and 60 kg N ha−1 when planting is delayed beyond July 7 in the Sahel and Sahel-Sudan agroecological zones, respectively.

Growth and yield of maize (Zea mays L.) as influenced by cropping pattern and weed control treatments in the forest – savanna agro-ecological zone of southwest Nigeria

Growth and yield of maize (Zea mays L.) as influenced by cropping pattern and weed control treatments in the forest – savanna agro-ecological zone of southwest Nigeria

Integrating traditional knowledge with modern breeding techniques: A case study of cattle production in Nigeria's southern guinea and derived savanna agroecological zones

Nomadic pastoralists and agropastoralists are the primary custodians of cattle production in Nigeria, they operate a low external input production system which is proving difficult to modernize especially in the areas of breeding and reproduction for genetic improvement. This study was carried out to gather historical, phenotypic, and perceived genetic information associated with cattle breeding and reproduction practices of the nomadic pastoralists and agropastoralists in the Nigeria Southern Guinea Savanna and Derived Savanna agroecological zones through interviewer-led focus group meetings. The study revealed that the respondents operate similar breeding practices which are native knowledge and practices preserved and transmitted over many generations. The practices are communal in nature and consider climate conditions as well as being comparably similar with the modern scientific standards, hence it was concluded that the respondents have the potential to easily adopt the modern approach of animal breeding and reproduction. These findings suggest a pathway for integrating traditional knowledge with contemporary breeding techniques to enhance cattle production. Future research should explore specific strategies to facilitate this integration and evaluate its impact on productivity and sustainability in the agro-ecological zones

Optimization of Water Management for Green Pepper Production in a Water-Limiting Tropical Savanna Agroecological Zone Based on Crop Water Productivity

This study aimed to determine the optimum levels of irrigation regime and irrigation schedule based on crop water productivity for the sustainable production of green pepper in a water-limiting tropical savannah agroecological zone. The study was conducted at the Hydro Farm of MotorKing Company Limited in the Tamale Metropolis, Northern Region, Ghana. The experimental design was a 2 × 3 factorial experiment laid out in a randomized complete block and replicated five times. Irrigation schedule at two levels (one-time daily application and split daily application at 60% morning and 40% evening) and irrigation regime at three levels (100% ETc, 80% ETc, and 60% ETc) were the factors. The “Yolo Wonder” variety of green pepper was the test crop. The crop was planted at a planting distance of 0.3 m within rows and 0.5 m between rows. Treatments were applied using a drip irrigation system. Crop water requirements (ETc) of green pepper were estimated using the CROPWAT model. Crop yield and water applied under each treatment were determined. Crop yield was measured at harvest as the total weight of fruits per hectare. Crop water productivity was determined under each treatment as crop yield per unit of water consumed. Data analysis was done in Genstat (12th edition). Analysis of variance (ANOVA) and Duncan’s multiple range test at 5% level of significance were employed to separate differences in treatment means. The results suggest that both irrigation regime and irrigation schedule have significant influence on the yield and crop water productivity of green pepper. Irrigating at 60% ETc and split irrigation (60% morning and 40% evening) gave significantly higher yields and crop water productivity compared to the other levels of the factors. This study demonstrated that irrigation schedule and irrigation regime are important factors to consider in the optimization of water management for green pepper; however, further research is needed to identify the optimal levels of these factors and the most effective irrigation strategies for the crop in different environments.

Soil properties affecting soil organic carbon stock of different land use types in two agro-ecological zones of Nigeria

Soil organic carbon (SOC) stock is the carbon proportion that is of biological origin stored with respect to soil depth. It is more prone to loss than soil inorganic carbon. High sequestration of SOC in soil is germane to the improvement of soil quality and mitigating impact of climate change. Thus, this study was carried out to evaluate soil properties affecting SOC stock in the two agro-ecological zones, namely Upland Rainforest (Ado-Ekiti) and southern Guinea Savanna (Kabba) agro-ecological zones of Nigeria, with respect to three selected land use types; arable, oil palm and wetland. Random collection of soil samples was carried out at four varying depths (0-15, 15-30, 30-45, and 45-60 cm) for evaluation of soil properties. The SOC stock regression models for the two agro-ecological zones showed that land use, SOC, pH, SOM (soil organic matter), Ex-K, Ex-Ca, Ex-Mg (exchangeable potassium, calcium, magnesium, respectively), BD (bulk density), and gravel content would predict variation in SOC stock in the two agro-ecological zones with coefficient of determination (R2) values of 0.952 and 0.996 for Kabba and Ado-Ekiti respectively. Principal component analysis identified that in the soil of the southern Guinea Savanna agro-ecological zone, SOC, CEC, EA, Ex-Na, land use, clay content, and soil depth with Eigenvalues &gt; 1 explained 80.58% of sample variance while in the soil of the Upland Rainforest agro-ecological zone, Ex-Ca, SOC, Ex-Na, EA, sand and silt contents with Eigenvalues &gt; 1 explained 78.81% of sample variance as potential determinants of SOC stock.

Biochar for Wastewater Treatment and Soil Improvement in Irrigated Urban Agriculture: Single and Combined Effects on Crop Yields and Soil Fertility

This work evaluated the agronomic and soil fertility effects of using municipal wastewater or anaerobically treated wastewater for irrigation and applying biochar to a soil from the Guinea savanna agroecological zone of Ghana. For this purpose, untreated municipal wastewater (WW), the effluent of an anaerobic wastewater filtration system (TWW), and clean water (CW) were used as irrigation water in a pot trial. Additionally, rice-husk biochar in the form of raw biochar (RB), water-washed biochar (WB), and biochar used as wastewater filter material (FB) were added to the soil, testing the influence on soil fertility and crop yield. Lettuce and carrot were selected for the pot study, grown on soil mixed with the biochar types at 20 t ha−1 and irrigated with either WW, TWW, or CW. Our results indicated higher crop growth morphology and yields (up to 90% increase) by WW and TWW than CW. The average yield of carrot (34.1 g pot−1) and lettuce (29.3 g pot−1) with TWW irrigation were the highest, followed by 31.2 and 27 g pot−1 with WW, then the lowest yields of 21.7 and 19.5 g pot−1 of carrot and lettuce irrigated with CW respectively. Compared to WW, TWW was more beneficial to plant development, causing an up to 10% increase in crop yields. Soils with FB and WB produced similar agronomic effects and plant nutrient concentrations but were lower than pots amended with RB. Nevertheless, combining RB with TWW showed increasing effects on pH, CEC, and P availability in the highly weathered acidic soil. The results suggest a beneficial effect of biochar-filtered wastewater on soil fertility and crop growth, offering the potential to enhance resource use efficiency in irrigated urban agroecosystems.

Assessment of Maize (Zea mays) Genotypes for Seed Metrics, Agronomic Performance, Yield and Nutritional Content in the Southern Savanna Agro-ecological Zone of Nigeria (Wukari as Case Study)

Maize is ranked as one of the cereal crops with high yield potential globally and may be considered very important for countries like Nigeria, where there is an increasing demand for food to meet the demand of its teeming population. Five varieties of maize (Sammaz 52, M1217, M1155, Oba 98 and Oba super II) obtained seed companies and mostly grown in Wukari were evaluated during the 2020/2021 cropping seasons for yield, agronomic performance, seed metrics and nutritional quality at the Research and Teaching Farm of the Federal University Wukari, Taraba State. Having four replications, the experiment was set up using Randomized complete Block Design (RCBD). Obtained data on agronomic characters, yield and nutrient qualities revealed significant differences among the varieties for days to tasseling, silking, grain yield, nutritional content, number of nodes, ear height (cm), hundred seed weight (g), number of seed rows, seed length at P&gt;0.05. Height at matirity showed significant difference, with Oba98 having the highest (195.25 cm) value. M1217 recorded superiority (24.95g) over the other varieties for 100 seed weight. Laboratory Analysis was conducted to determine the essential amino acid and nutritional content of the five maize varieties. There was a significant variation in the crude protein content of the five varieties with the SAMMAZ52 having the highest value (13.14%). Oba 98 recorded highest essential amino acid such as Methionine (2.39), Lysine (2.33) and Tryptophan (1.43) over the other varieties assessed.

Simulating potential yield of rainfed soybean in northeast Nigeria

We used the CROPGRO-Soybean model to simulate the production potential of rainfed soybean in northeast Nigeria. Data from ten soybean experiments conducted under optimal conditions in 2016–2018 at Kano and Dambatta in the Sudan savanna (SS) agroecological zone were used to determine the cultivar coefficients and calibrate the model for the varieties TGX 1448–2E and TGX1951–3 F. The model was evaluated with data from four phosphorous response trials conducted at Zaria and Doguwa in the northern Guinea savanna (GS) of Nigeria between 2016 and 2018. Results show that the CROPGRO-Soybean model was able to accurately simulate soybean growth and grain yield with low RMSE and high d-index values. Consequently, the model was used to investigate the rainfed yield potential of the two varieties in 24 sites in northeast Nigeria under different sowing windows using 30-year (1985–2014) weather data. The result shows that soybean can be grown in northeast Nigeria, but yield performance is dependent on location, variety and sowing window. The simulated yield was higher in the SS than in the GS agro-ecozone despite the longer growing period in the later. Low yield was simulated for TGX 1448–2E for most of the sites. The yield of TGX1951–3 F was above a threshold of 1500 kg ha−1 in 5 out of 12 sites in the GS and 7 out of 12 sites in the SS, suggesting that this variety is the most suitable for cultivation in northeast Nigeria. Sowing TGX 1951–3 F can be delayed to July 16 at Gwaskara, Nasarawo Demsa and Tawa in the GS and at Briyel, Lakundum, Jara Dali, Kurbo Gayi, and Mathau in the SS with a low-risk of crop failure. The desired yield will be achieved at Chikala and Puba Vidau with a significantly low risk of crop failure for all sowing windows. The results from this study suggest that the CSM-CROPGRO-Soybean model can be a valuable tool in determining the right variety and sowing window for soybean production in targeted agroecological zones in northeast Nigeria.

Antibiotic Resistance of Bacterial Isolates from Smallholder Poultry Droppings in the Guinea Savanna Zone of Nigeria.

There is a growing risk of antibiotic resistance (AR) in smallholder poultry (SP). This study, therefore, aimed to investigate AR pattern of bacterial isolates from SP in the Guinea Savanna agro-ecological zone of Nigeria. A total of 120 fresh poultry droppings were aseptically collected, randomly, from two tropically adapted (FUNAAB Alpha and Noiler) and local chickens. The chickens were raised either using ethnoveterinary medicines (n = 60) or antibiotics (n = 60). Bacterial isolates were characterized and analyzed using standard protocols, and appropriate statistical tools. Compared to Pseudomonas spp. (2.5%) and Klebsiella spp. (5.8%), Salmonella spp. (57.5%) and Escherichia coli (34.2%) were the most prevalent (χ2 = 96.67; p < 0.001). Prevalence of bacterial species was significantly (p = 0.024; Odds Ratio = 2.552) influenced by antibiotics usage. All four species were multi-drug resistant. In total, 30% of the isolates had a multiple AR index ≥ 0.2. Bacterial isolates from FUNAAB Alpha (58.0%) and Noiler (44.0%) were highly resistant to quinolones, while isolates from the local chickens (22.6%) were most resistant to aminoglycosides. Bacterial species isolated from FUNAAB Alpha and local chickens exhibited the lowest and highest percentage of AR, respectively. Clustering of isolates with similar antibiogram revealed inter-species dependence with possibility for inter-species gene transfer. These findings provide a background to investigate the metagenomics of local and improved chickens for AR.

EFFECT OF TRANSPLANTING DATES ON GROWTH AND YIELD COMPONENTS OF PEPPER (Capsicum Spp) IN BADEGGI, NIGERIA

Field experiment were conducted to determine the effects of transplanting date on growth and yield of pepper (Capsicum Spp) varieties at the irrigated Research farm of the National Cereal Research InstituteBadeggi, Niger State, Nigeria in 2018 and 2019 rainy seasons were assessed. The experiment was a 5 x 4 factorial laid out in a randomized complete block design with three replication and consisted of five pepper varieties (Tabasco, Bell pepper, Rocoto, Hottest pepper and South Africa pepper) and four transplanting dates (3rd June, 3rd July, 3rd August, and 3rd September). Result indicated significant differences (P&lt;0.05) among the pepper varieties and transplanting dates. Rocoto variety was the tallest variety in both years while Bell pepper was the shortest. Bell pepper had the largest leaf area (49.88, 41.90 and 41.19cm2 in 2018 and 46.78, 46.34 and 40.99cm2 in 2019 at 6, 9, 12 weeks after transplanting WAT respectively). Fresh and dry fruit yields from Rocoto variety superseded other variety by 21-82% and 22-85% in 2018 and 27-83% and 35-87% in 2019. Pepper transplanted in July and significantly (P&lt;0.05) higher number of leaves per plant, larger leaf area, number of branches per plant and taller plants than other transplanting dates. Also, transplanting dates had significant effects (P&lt;0.05) on pepper phonological and yield components. 3rd September transplanting attained 50% of flowering, fruiting and ripening earlier than other dates in both years. July transplanting date had the highest fresh (13.40 and 13.87t/ha-1) and dry (9.88 and 9.15 tha-1) fruit yields in both years. Fresh and dry fruit yields from plants transplanted in 3rd July susperseded other dates in both years. Findings from this experiment show that transplanting Rocoto variety in July would guarantee high productivity of pepper in Badeggi, Southern Guinea Savanna agro-ecological zone of Nigeria.

Assessing the Spatial Variability of Soil Properties to Delineate Nutrient Management Zones in Smallholder Maize-Based System of Nigeria

Spatially explicit information on soil variability is relevant for agronomic decisions; however, such information is limited in the northern Guinea savanna (NGS) agroecological zone of Nigeria. This study was conducted to delineate soil nutrient management zones (MZs), based on spatial variability of soils in the smallholder maize-based farming system within the NGS. Two hundred and eighty-nine soil samples were analyzed for some physical and chemical properties. Principal component analysis (PCA) was used to aggregate the soil properties into four principal components, which accounted for about 60% of the variation in the data, and spatial variability was assessed with a semivariogram. The ordinary kriging technique was used to predict soil properties at unsampled locations, while weighted overlay analysis was conducted to delineate nutrient management zones. Results showed that total nitrogen (0.06%), available phosphorus (5.6 mg kg−1), organic carbon (0.66%), and effective cation exchange capacity (5.6 cmol(+) kg−1) are below optimal requirement for maize production. Four MZs were identifiable in the region with the highest fertility (MZ3 and MZ4) associated with the northern area but covering a relatively small part (9.1%). The differences observed in soil properties among the MZs suggest that each zone requires different agronomic management, especially in relation to fertilizer application.

Evaluation and application of the CROPGRO-soybean model for determining optimum sowing windows of soybean in the Nigeria savannas

Soybean production is limited by poor soil fertility and unstable rainfall due to climate variability in the Nigeria savannas. There is a decline in the amount and duration of rainfall as one moves from the south to north of the savanna zones. The use of adapted soybean varieties and optimum sowing windows are avenues to increase productivity in the face of climate variability. Crop simulation models can be used as tools for the evaluation of alternative management options for a particular location, including fertilizer application rates, plant density, sowing dates and land use. In this study, we evaluated the performance of the Cropping System Model (CSM)-CROPGRO-Soybean to determine optimum sowing windows for three contrasting soybean varieties (TGX1835-10E, TGX1904-6F and TGX1951-3F) cultivated in the Nigeria savannas. The model was calibrated using data from ten field experiments conducted under optimal conditions at two sites (BUK and Dambatta) in Kano in the Sudan savanna (SS) agro-ecology over four growing seasons. Data for model evaluation were obtained from independent experiment for phosphorus (P) response trials conducted under rainfed conditions in two locations (Zaria and Doguwa) in the northern Guinea savanna (NGS) zone. The model calibration and evaluation results indicated good agreement between the simulated and observed values for the measured parameters. This suggests that the CROPGRO-Soybean model was able to accurately predict the performance of soybean in the Nigeria savannas. Results from long-term seasonal analysis showed significant differences among the agro-ecologies, sowing windows and the soybean varieties for grain yield. Higher yields are simulated among the soybean varieties in Zaria in the NGS than in Kano the SS and Jagiri in the southern Guinea savanna (SGS) agro-ecological zones. Sowing from June 1 to July 5 produced optimal yield of TGX1951-3F and TGX1835-10E beyond which yield declined in Kano. In Zaria and Jagiri the simulated results show that, sowing from June 1 to July 12 are appropriate for all the varieties. The variety TGX1951-3F performed better than TGX1904-6F and TGX1835-10E in all the agro-ecologies. The TGX1951-3F is, therefore, recommended for optimum grain yield in the savannas of northern Nigeria. However, the late maturing variety TGX1904-6F is not recommended for the SS due to the short growing season in this zone.

Zinc application rate for optimal profitability of maize production systems in the savanna agroecological zones of Northern Ghana

Although the critical role of zinc (Zn) in maize nutrition and productivity is well documented, there is still a need to determine the most economically justifiable Zn application rate for maize production, particularly in the savanna agroecological zones (AEZs) of northern Ghana where such study is lacking. In a three-year study at six locations across the AEZs, we compared seven Zn application rates, ranging from 0 to 15 kg ha−1 in 2.5 kg intervals, to quantify maize yield responses and determine the economically optimal Zn rate for maize production. Across all experimental sites and for the three growing seasons, maize grain yield with each treatment followed the order 15 kg Zn ha−1 = 12.5 kg Zn ha−1 = 10 kg Zn ha−1 = 7.5 kg Zn ha−1 > 5 kg Zn ha−1 > 2.5 kg Zn ha−1 > control, suggesting that 7.5 kg Zn ha−1 is the optimal Zn application rate. However, based on agro-input prices at the local level and the farm-gate prices of maize, the potential gross profit resulting from Zn application was maximized at 5 kg Zn ha−1. From the combined results, we conclude that, when the production objective is for yield optimization only, an application rate of 7.5 kg Zn ha−1 provides the best results. However, unless premium prices are paid for Zn-enriched maize grains, then Zn application rate of 5 kg ha−1 is economically justified for sustainable and profitable maize production in the Zn-deficient soils of the savanna AEZs of northern Ghana.