Savanna Agro-ecological Zone Research Articles

Defining Crop–Climate Departure in West Africa: Improved Understanding of the Timing of Future Changes in Crop Suitability

The future climate is projected to change rapidly with potentially severe consequences for global food security. This study aims to improve the understanding of future changes in the suitability of crop growth conditions. It proposes a definition of crop realization, of the climate departure from recent historical variability, or crop–climate departure. Four statistically downscaled and bias-corrected Global Climate Models (GCMs): CCCMA, CNRM5, NOAA-GFDL, and MIROC5 performed simulations for the period 1960–2100 under the Representative Concentration Pathway RCP8.5 scenario to compute 20 year moving averages at 5-year increments. These were used to drive a crop suitability model, Ecocrop, for eight different crops across the three Food and Agriculture Organizations (FAO) AgroEcological Zones (AEZs) of West Africa (Guinea, Sahel, and Savanna). Simulations using historical climate data found that all crops except maize had a suitability index value (SIV) ≥0.50 outside the Sahel region, equivalent to conditions being suitable or strongly suitable. Simulations of future climate reveal that warming is projected to constrain crop growth suitability for cassava and pineapple in the Guinea zone. A potential for the northward expansion of maize is projected by the end of the century, suggesting a future opportunity for its growth in the southern Sahel zone. Crop growth conditions for mango and pearl millet remain suitable across all three AEZs. In general, crops in the Savanna AEZ are the most sensitive to the projected changes in climate. The changes in the crop–climate relationship suggests a future constraint in crop suitability, which could be detrimental to future food security in West Africa. Further studies to explore associated short- and long-term adaptation options are recommended.

Smallholder farmers' livelihood adaptation to climate variability and ecological changes in the savanna agro ecological zone of Ghana

Climate variability and ecological changes have consequently altered life and natural livelihood-sustaining systems leading to socio-cultural, economic and environmental challenges and vulnerabilities. The risk factors are very high and the impacts will raise the developmental impediments of safeguarding livelihood security and poverty eradication in Sub-Saharan Africa. Adaptation to climate and ecological variation, though recognized as pressing and necessary, operates in the context of numerous uncertainties and unknowns. Previous studies on climate adaptation tried to identify universal patterns of coping rather than differentiating between agro ecological zones, villages and types of households. This paper uses case studies from two rural communities in the Savanna agro ecological zone of Ghana to explore smallholder farmers' responses to climate and ecological variation effects on their livelihood activities that have emerged since the mid-1980s. Results suggest that smallholder farmers use various coping, on-farm and off-farm adaptation strategies to ameliorate the negative impacts of climate and ecological changes on their livelihood. Coping measures such as selling household assets, migration of the entire households and decreasing food consumption/changing diets can be damaging. On –farm adaptation strategies such as varying planting dates, use of drought tolerant crop varieties, soil conservation strategies are based on farmers indigenous knowledge passed down from generations. To ensure sustainability of local adaptation strategies, there is the need for exchange of knowledge between and among smallholder farmers and formal institutions through the recognition and empowerment of local residents and collective actions.

Climate change impact on water- and nitrogen-use efficiencies and yields of maize and sorghum in the northern Benin dry savanna, West Africa

Climate change and variability challenge crop productivity and resource use efficiency in West Africa. Despite abundant research on climate change impact on crop yields and food security, little is known about climate change effects on the resource use efficiencies of the main staple crops in the dry savanna agro-ecological zone of northern Benin, West Africa. This study assessed the impact of climate change on water- and N-use efficiencies, and yields of maize and sorghum in the dry savanna of northern Benin considering three soil fertility management options (return of crop residues, mineral NPK fertilizer application, and combinations of both) and three bias-corrected ensemble mean predictions (BNU-ESM, CanESM2, and MPI-ESM-MR models) of future climate (2080–2099) under Representative Concentration Pathways (RCPs) of 2.6, 4.5, and 8.5. Seasonal rainfall is projected to decrease by 2% under RCP 2.6 and by 4% under RCP 4.5, and to increase by 1% under RCP 8.5 relative to the baseline mean (1986–2005). Increasing trends in minimum temperature of +1.0 °C (RCP 2.6), +2.0 °C (RCP 4.5), +4.7 °C (RCP 8.5) and maximum temperature of +1.1 °C (RCP 2.6), +2.0 °C (RCP 4.5), +4.6 °C (RCP 8.5) are also predicted. Solar radiation was projected to decrease by about 0.4 MJ m−2 d-1. Under these projected climate scenarios, both CERES-Maize and CERES-Sorghum simulated positive responses in aboveground biomass accumulation during the vegetative growth stages. The predicted increase in aboveground biomass growth will be largest under RCP8.5 and smallest under RCP 2.6. This impact can be enhanced by improved soil fertility management, albeit with a crop-specific magnitude. Across the soil fertility management options, CERES-Maize predicted decreases in water-use efficiency by 17–53%, partial factor productivity of nitrogen (N) by 10–47%, and internal N-use efficiency by 5–33% for maize. Similarly, CERES-Sorghum simulated decreases in water-use efficiency (23–51%), partial factor productivity of N (22–49%), and internal N-use efficiency (13–47%) for sorghum. The largest overall loss in resource efficiency and yield were predicted for the RCP 8.5 scenario. The projected climate change for the dry savanna in northern Benin will likely reduce water- and N-use efficiencies as well as grain yields of maize and sorghum considerably but these results should be treated with caution due to shortcomings in the models structure for dealing with effects of enhanced CO2. For reliable assessments of climate change impact on WUE, it is critically important to update parameterization and code of the CERES crop models in DSSAT to have a sufficiently strong effect of CO2 on stomatal conductance and on transpiration.

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

Response of rice varieties to nitrogen fertilization under irrigation at Talata Mafara, Sudan savanna

A field experiment was conducted during the dry seasons of 2012 and 2013 in Irrigation Research Station, Talata Mafara, Zamfara State, Latitude 12°34ʹ00ʺ N and Longitude 6°04ʹ00ʺ E 488m above sea level in the Sudan savanna agro-ecological zone. The objective of the research was to test the effect of rice varieties to various levels of nitrogen (N) fertilization under irrigation. The experiment was laid out in a Complete Randomize Block Design (CRBD) using split plot arrangement and was replicated three times. Three rice varieties (Faro 44, 45 and 57) were allocated to the main plot and three nitrogen levels (60, 120 and 180 kg N ha-1) were allocated to the sub plot. The gross and net plot sizes were 5 x 4 and 3 x 3 m respectively. Weeds were controlled using Glyphosate as pre-plant, Butachlor as pre-emergence and Orizo plus as post-emergence herbicides and supplemented with hand pulling at 9 WAS. Fertilizer was applied in two split doses. First half was applied at planting using NPK and the remaining half at 6 WAT using Urea (46 % N). Data collected were analyzed using analysis of variance (ANOVA) and significant means were separated using DMRT at 5 % level of probability. The result of the effect of variety on growth parameters showed that Faro 44 recorded higher days to 50 % anthesis but was significantly (p≤0.05) shorter in height than Faro 57. The effect of the treatment on yield parameters showed that Faro 44 recorded higher thrashing percentage, 1000-grain weight and number of grain panicle-1 significantly (p≤0.05) higher than Faro 45 and 57 in all the seasons. Increasing nitrogen levels from 60 kg N ha-1 significantly increased growth and yield parameters. Application of 180 kg N ha-1 on Faro 44 is hereby recommended for rice growing in the ecological zone.

Quantifying Variability in Maize Yield Response to Nutrient Applications in the Northern Nigerian Savanna

Diagnostic on-farm nutrient omission trials were conducted over two cropping seasons (2015 and 2016) to assess soil nutrients related constraints to maize yield in the northern Nigerian savanna agro-ecological zone and to quantify their variability. Two sets of trials were conducted side by side, one with an open pollinated maize variety (OPV) and the other one with a hybrid maize variety and each set had six equal treatments laid out in 198 farmers’ fields. The treatments comprised (i) a control, (ii) a PK (‘−N,’ without N), (iii) an NK (‘−P,’ without P), (iv) an NP (‘−K,’ without K), (v) an NPK and (vi) an NPK + S + Ca + Mg + Zn + B (‘+SMM,’ NPK plus secondary macro- and micro-nutrients). Moderate to a large variability in most soil characteristics was observed in the studied fields. Consequently, cluster analysis revealed three distinct yield-nutrient response classes common for the two types of maize varieties. These define classes were fields that have (i) no-response to any nutrient, (ii) a large response to N and P and (iii) a large response to N alone. Although overall yield performance of OPV and hybrid varieties was similar, a distinct fourth class was identified for the hybrid variety, (iv) fields with a large response to N and secondary macro- and micro-nutrients. The results indicate that the large variability in soil nutrients related constraints need to be accounted for to optimize maize yield in the northern Nigerian savanna. The development of field- and area-specific fertilizer recommendations is highly needed, using simple decision support tools that consider variable soil fertility conditions and yield responses as obtained from this study.

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.

CERES-Maize and CERES-Sorghum for modeling growth, nitrogen and phosphorus uptake, and soil moisture dynamics in the dry savanna of West Africa

Sustainable production practices are needed to enhance water and nutrient use efficiencies in the cropping systems of West Africa, especially in face of predicted climate change for the region. Crop simulation models may assist in exploring alternative management systems for optimizing water and nutrient use efficiencies, increasing crop production, and easing food insecurity. The twofold objectives were: (i) to access the ability of the CERES-Maize and CERES-Sorghum models for predicting yields, nitrogen (N) and phosphorus (P) uptake, and in-season soil water and N dynamics during maize and sorghum growth; (ii) to use the models to assess the effects of different nutrient management strategies on soil C and N, and crop water and N use efficiencies considering 30 years of historical weather variability in the dry savanna agro-ecological zone of northern Benin, West Africa. Both models were calibrated with data from a researcher-managed field trial (2014) and validated with independent findings (2015). The models were next evaluated with datasets collected from researcher- and farmer-managed field trials conducted under rainfed and supplementary irrigation conditions (2014–2015). The parameterized CERES-Maize and CERES-Sorghum models accurately predicted biomass accumulation with a normalized root mean square error (nRMSE) of 18% and 17%, respectively, and an index of agreement (d) of 0.98 for both crops in non-nutrient- and non-water-stressed conditions. Under rainfed and rainfed with supplementary irrigation conditions, both with and without mineral fertilizer application, CERES-Maize predicted biomass accumulation with nRMSE (d) of 10–22% (0.96–0.99), while CERES-Sorghum reached accuracies of 13–29% (0.97–0.99). Grain yield was simulated with nRMSE (d) of 19% (0.93) and 15% (0.89) by CERES-Maize, and 16% (0.91) and 15% (0.80) by CERES-Sorghum in researcher-managed and farmer-managed fields, respectively. CERES-Maize predicted reasonably well nutrient uptake with nRMSE (d) ranging from 14 to 40% (0.89–98) for N and between 24 and 49% (0.90–0.98) for P. Similarly, CERES-Sorghum simulated N uptake with nRMSE of 17–49% and d-values of 0.87–0.98, and P uptake with nRMSE of 42–62% and d-values of 0.82–0.93. Values of nRMSE (d) between predicted and measured in-season soil water and N dynamics were 6–13% (0.61–0.87) and 46–58% (0.61–0.76) with CERES-Maize, and 14–20% (0.75–0.89) and 35–56% (0.62–0.82) with CERES-Sorghum, respectively. The models simulated improved soil organic C and inorganic N, water and N use efficiencies, and grain yields with the integrated soil-crop management system compared to un-amended soil and high mineral fertilizer use options under 30 years of weather variability. Both models are thus appropriate tools not only to explore potential impacts of predicted climate change on soil water and nutrient use efficiencies, but also to frame more sustainable intensification measures in the maize- and sorghum-based production systems of West Africa.

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

Tomato Fruits Yield and Soil Properties as Affected by Salts Application and Irrigation Schedule at Jega, Sudan Savanna Agro-ecological Zone

Tomato Fruits Yield and Soil Properties as Affected by Salts Application and Irrigation Schedule at Jega, Sudan Savanna Agro-ecological Zone

Agronomic evaluation of testcrosses of drought-tolerant maize (Zea mays L.) inbred lines using different selection index methods

ABSTRACTThe present study aims at identifying potentially high-yielding testcross maize hybrids using different selection indices that consider agronomic traits other than grain yield alone. Forty-one (41) testcross hybrids developed from 20 elite drought-tolerant maize inbred lines and two inbred testers plus three hybrid checks were evaluated in the rainy seasons of 2013 and 2014 in Ogbomoso in the derived savanna agroecological zone of Nigeria. Hybrids were planted in each year in 11 × 4 lattices with two replications. Testcross hybrids and checks exhibited significant differences for all measured traits except ear height, husk cover and number of ears per plant. Grain yield of hybrids and checks averaged over the 2 years varied from 3117 to 8393 kg ha−1 with a mean of 5935 kg ha−1. Top 11 hybrids produced vigorous plants, each yielding >7000 kg ha−1. Base index and multivariate index methods identified EXL11 × 9071 whereas base index and Smith–Hazel selection index methods identified EXL18 × 9071 as superior hybrids at 5% selection intensity. These hybrids will be considered for advanced breeding program and release to farmers as high-yielding drought-tolerant hybrid maize varieties in the increasingly drought-prone derived savanna agroecology of Nigeria.

Regression tree analysis for predicting body weight of Nigerian Muscovy duck (Cairina moschata)

Morphometric parameters and their indices are central to the understanding of the type and function of livestock. The present study was conducted to predict body weight (BWT) of adult Nigerian Muscovy ducks from nine (9) morphometric parameters and seven (7) body indices and also to identify the most important predictor of BWT among them using regression tree analysis (RTA). The experimental birds comprised of 1,020 adult male and female Nigerian Muscovy ducks randomly sampled in Rain Forest (203), Guinea Savanna (298) and Derived Savanna (519) agro-ecological zones. Result of RTA revealed that compactness; body girth and massiveness were the most important independent variables in predicting BWT and were used in constructing RT. The combined effect of the three predictors was very high and explained 91.00% of the observed variation of the target variable (BWT). The optimal regression tree suggested that Muscovy ducks with compactness &gt;5.765 would be fleshy and have highest BWT. The result of the present study could be exploited by animal breeders and breeding companies in selection and improvement of BWT of Muscovy ducks.

Effects of Farmyard Manure and Integrated Weed Management on Okra Growth Parameters (Abelmoschus Esculentus (L.) Moench) at Dadinkowa

Field trials were conducted during 2011 and 2012 cropping seasons at the Teaching and Research Farm of Federal College of Horticulture Dadinkowa in Sudan savanna agro-ecological zone of Nigeria. The objectives of the trial were; to determine the effects of farmyard manure and integrated weed management on okra growth. The treatments were laid out in a split-plot design with farmyard manure rates occupying the main plots; while integrated weed management rates were allocated to the sub-plots and replicated three times. Farmyard manure was applied to affected plots a week before sowing okra, while pendimethalin 500 EC was applied pre-emergence at the rate of 2.5 kg a.i. ha-1 immediately after sowing. Results revealed that the effects of farmyard manure and integrated weed management were significant on plant height (P≤5%), number of leaves plant-1, number of branches plant-1 and leaf area plant-1. It was observed that the control treatments of no farmyard manure applied and no weed control significantly gave lower means on okra growth parameters, while application of 4 t ha-1 of farmyard manure and weeding once at 2 + 4 + 6 + 8 WAS together with 2.5 kg a.i. ha-1 of pendimethalin 500 EC significantly gave higher means on the same traits, as well as integrated weed management.