Northern Guinea Savannah Research Articles

Effect of intra-row spacing and weeding frequency on the yield performance of sesame/cowpea intercrop

Field experiments were conducted simultaneously at the Abubakar Tafawa Balewa University Teaching and Research Farm, Bauchi, and Bauchi State Agricultural Development Programme experimental sites, Bauchi (Lat. 100 17\'N 90 49’ E, and 609m above sea level), in the Northern Guinea savannah ecological zone of Nigeria during the 2002 wet season to study the response of sesame/ cowpea mixture to weeding frequency and intra-row spacings. The treatments were laid out in a randomised complete block design with three replications. The result showed that the number of capsules per plant, 100-seed weight, capsules and grain yield per hectare of sesame were significantly (P<0.05) increased by one weeding frequency only at location I. The parameters were not significantly affected by weeding frequency in location II. The capsules length, number of capsules per plant, capsules and grain yield were significantly (P<0.05) affected by intra-row spacings. The capsules and grain yield of sesame increased significantly (P<0.05) with decreasing intra-row spacing and conversely capsules length and number decreased with decreasing intra-row spacing. The number of pods of cowpea significantly (P<0.05) increased by two weeding frequencies at location I and pod yield per hectare was also increased significantly by twice weeding at location II. All the other parameters such as pod lands, seeds per pod, 100-seed weight and grain yield per hectare were not significantly affected by the treatments. The interaction between the intra-row spacings and weeding frequency were significant in affecting number of seed per capsules and 100-seed weight of sesame at location I, and number of pods and seed per pod of cowpea at location II. Intra-row spacing of 30cm and twice weedings produced the highest number of seed per capsules (68.2) and 20cm intra-row spacings with twice weeding produced the highest 100- seed weight. However, 30cm intra-row spacings with one weeding had highest number of pods (24.3) in cowpea plant and also 30cm intra-row spacing with twice weedings produced the highest seeds per pod in cowpea.

Extractable Micronutrients In Relation To Physico-Chemical Properties Of Soils In Four Ecological Zones Of Nigeria

Micronutrients play an important role in crop production. Discerning their bioavailability is a necessity to diagnose deficient or toxic levels. Yet, the non-static nature of the complex reservoir of mineral nutrients (the soil) is implied in biological, physical and chemical changes that also affect the supply of micronutrients to crops. In this study, total and 0.01 N HCl extractable Mn, Zn, Fe and Cu were determined in 25 soil samples collected from various locations representing the major soil types and parent materials found in the Rainforest, Derived savannah, Coastal rainforest and Northern guinea savannah ecological zones in Nigeria. The resulting analytical values were subsequently related to the physico-chemical properties of the soils. There were substantial variations in the amounts of total and extractable micronutrients. Total Mn and Zn ranged from 24.00 to 114.00 and 14.00-54.00 mg kg -1 with means of 60.55 and 23.55mg kg -1 , respectively while the 0.1N HCl-extractable Mn, Fe, Cu and Zn values varied from 0.03-14.21, 10.00-100.00, 0.27-0.46 and 0.60-95.50 mg kg -1 , the means being 4.82, 62.32, 0.35 and 6.91mg kg -1 , respectively. Majority of the soils are not deficient in Mn and Zn while none was deficient in Fe and Cu. Extractable Mn correlated significantly with organic carbon (OC) (r=-0.413) while total Zn correlated with soil pH (-505) and OC (+0.521). Organic matter and the clay fractions had strong influence on the contents of Mn. Soil reaction (pH) and could be used to predict Zn contents whereas there was no assurance that 0.1NHCl-extractable Fe and Cu values could be predicted from the physico-chemical properties. In view of their relatively low correlation coefficients with soil properties, it appears that the 0.1N HCl test procedure proved to be a non- promising extractant for the determination of available micronutrients in the soils tested. KEY WORDS: 0.01N HCl extractable, Bioavailability, Micronutrients, Physico-chemical properties, Relationship. Global Journal of Pure and Applied Sciences Vol.11(2) 2005: 197-200

Natural occurrence of Fusarium and subsequent fumonisin contamination in preharvest and stored maize in Benin, West Africa

The natural occurrence of Fusarium and fumonisin contamination was evaluated from 1999 to 2003 in both preharvest and stored maize produced by small-scale farmers in four agroecological zones of Benin. Mycological analyses revealed a predominance of both Fusarium and Aspergillus in maize samples compared to other genera. The two Fusarium species most commonly isolated from maize were Fusarium verticillioides (68%) and Fusarium proliferatum (31%). Atypical isolates of F. verticillioides with some characteristics of Fusarium andiyazi but apparently closer to F. verticillioides, because the isolates were all high fumonisin producers, were also found only on preharvest maize. Study of F. verticillioides strains showed the presence of extremely high fumonisin producers in Benin with total fumonisin levels ranging from 8240 to 16,690 mg/kg. Apart from 2002–2003, Fusarium occurrence was not significantly different from one zone to another, although a slight decrease was observed from south, humid, to north, drier. Fusarium occurrence varied somewhat from one season to another. It significantly decreased over the 6 months of storage. Widespread fumonisin occurrence in maize was observed. Most of the maize samples collected were found positive for fumonisin with levels ranging from not detected to 12 mg/kg in 1999–2000, 6.7 mg/kg in 2000–2001 and 6.1 mg/kg in 2002–2003. Fumonisin levels in maize were found to be significantly higher in the two southern zones during all the surveys. The highest mean total fumonisin level was detected in 1999–2000 in maize samples from the southern Guinea Savannah (SGS) (12 mg/kg), whereas in both 2000–2001 and 2002–2003, it was in samples from the forest mosaic savannah (FMS) (6.7 and 6.1 mg/kg, respectively). Fumonisin levels varied from one season to another and, throughout the storage time, showing a decreasing trend in each zone. However, this decrease was not significant every season. An increasing trend was observed during some seasons in the SGS and northern Guinea Savannah (NGS) zones. The results of this study emphasise that farmers and consumers, not only in Benin but also in other West African countries, should be alerted to the danger of fumonisin contamination in maize.

AN ASSESSMENT OF INTEGRATED STRIGA HERMONTHICA CONTROL AND EARLY ADOPTION BY FARMERS IN NORTHERN NIGERIA

Two sets of on-farm trials, each covering two years, were conducted in the northern Guinea savannah of Nigeria over the period 1999–2001, the objective being to compare integrated Striga hermonthica control measures (soybean or cowpea trap crops followed by maize resistant to Striga) with farmers' traditional cereal-based cropping systems. In both sets of trials, this proved to be highly effective in increasing productivity over the two year period, especially where soybean was used as a trap crop. Resistant maize after a trap crop increased the net benefit over the two cropping seasons in both trials by over 100% over farmer practice. However, in the second set of trials there was no significant increase in productivity between a trap crop followed by Striga resistant maize, and a trap crop followed by local maize especially where legume intercropping and fertilizer had been applied in the farmer practice. There was also no increase in productivity between two years' traditional cereal cropping and one year's local maize followed by Striga resistant maize. This indicates the importance of a legume trap crop in the first year in order to ensure high productivity in the second year, regardless of variety. Up to 20% of farmers obtained higher productivity from their own practices, notably intercropping of cereals with legumes and use of inorganic fertilizers. Leguminous trap crops and Striga resistant maize, together with two key management practices (increased soybean planting density and hand-roguing) were seen to be spreading both within and beyond the research villages, indicating that farmers see the economic benefits of controlling Striga. Survey findings show that explaining the reasons why control practices work can greatly increase the adoption of these practices. Wider adoption of Striga control will therefore require an extension approach that provides this training as well as encouraging farmers to experiment and adapt Striga control options for their local farming systems.

Cassava leaf harvesting as vegetables; a cause of vulnerability of cassava plant to cassava mosaic disease and eventual yield reduction: Ernte von cassavablättern als gemüse; eine ursache für die anfälligkeit der cassavapflanze für die cassava-mosaikkrankheit und für spätere ertragseinbußen

The consequence of harvesting young leaves of cassava as vegetable on the vulnerability of the crop to cassava mosaic disease (CMD) and on storage root yield was investigated using 30 cassava genotypes planted in IITA fields located in the humid forest (Port Harcourt : Onne), forest-savannah transition (Ibadan), southern guinea savannah (Mokwa) and northern guinea savannah (Zaria) agroecologies in Nigeria. Tender apical leaves and shoots of the cassava genotypes were removed from forty plants per cassava genotype with the same number of plants considered as control. Whitefly infestation, disease incidence (DI) and symptom severity (ISS) of the disease were assessed at monthly interval for six months and also at the ninth month after planting (MAP). Yield reduction due to this treatment was calculated as percentage harvest index (HI). Whitefly population fluctuated throughout the period of observation at all locations with higher population obtained generally for treated plants compared to control plants. Sprouting leaves of some treated genotypes were observed with severe mosaic symptoms, while corresponding control showed no mosaic symptoms. Contrarily, no remarkable difference was observed in Zaria between the mean ISS of treated and control cassava genotypes. There was a highly significant difference (P < 0.01) in DI and ISS among cassava genotypes across all locations. Also, there was a highly significant interaction (P < 0.01) in symptom severity between location (loc) and genotype, genotype and treatment (trt), loc and trt. Interaction between loc, genotypes and trt with regard to DI was highly significant at 2, 3 and 4 MAP, while with ISS, the interaction was highly significant all through the counting period. There was a positive relationship between DI and ISS on plants of genotypes 96/1039 and ISU. The percentage HI (27.4) of treated plants of genotype 95/0166 in Ibadan was remarkably lower than the value obtained for corresponding control (41.9) plants. Also, sharp distinction in% HI of treated (39.5) and control (43.8) ISU was observed in Onne with their respective ISS values as 3.7 and 3.2. Therefore, harvesting tender apical leaves and shoots of cassava as vegetables should be discouraged as it increases the severity of CMD infection in the regenerating shoots of cassava with attendant storage root yield reduction.

Variants of East African cassava mosaic virus and Its Distribution in Double Infections with African cassava mosaic virus in Nigeria.

In a survey for cassava mosaic begomoviruses conducted in 1997 and 1998 in Nigeria, East African cassava mosaic virus (EACMV) was detected by the polymerase chain reaction together with African cassava mosaic virus (ACMV) in 27 out of 290 cassava leaf samples of infected plants from 254 farmers' fields in five agroecological zones. One plant was infected with EACMV only. Five variant isolates of EACMV were observed based on their reactions to primers that could detect Cameroonian and East African strains of EACMV. Isolates of variants 1 and 3 occurred mostly in the derived or coastal and southern Guinea savannahs, while variants 4 and 5 predominated in the humid forest region. Isolates of variant 2 were widely distributed across the three agroecologies. EACMV was not detected in the northern Guinea savannah and arid and semiarid zones. Most doubly infected plants showed more severe symptoms than plants with single infection. Occurrence of EACMV variants together with ACMV detection and information about their distribution in Nigeria could be used for the selection of cassava clones in cassava mosaic disease resistance programs.

Direct and Residual Contributions of Symbiotic Nitrogen Fixation by Legumes to the Yield and Nitrogen Uptake of Maize (Zea mays L.) in the Nigerian Savannah

Field experiments were conducted to determine the direct and residual contributions of legumes to the yield and nitrogen (N) uptake of maize during the wet seasons of 1994 and 1995 at the University Farm, Abubakar Tafawa Balewa University, Bauchi, Nigeria, located in the Northern Guinea savannah of Nigeria. Nodulating soybean, lablab, green gram and black gram contributed to the yield and N uptake of maize either intercropped with the legumes or grown after legumes as a sole crop. Direct transfer of N from the nodulating soybean, lablab, green gram and black gram to the intercropped maize was 24.9–28.1, 23.8–29.2, 19.7–22.1 and 18.4–18.6 kg N ha–1, respectively. However, the transfer of residual N from these legumes to the succeeding maize crop was 18.4–20.0, 19.5–29.9, 12.0–13.7 and 9.3–10.3 kg N ha–1, respectively. Four years of continuous lablab cropping resulted in yields and N uptake of the succeeding maize crop grown without fertilizer N that were comparable to the yields and N uptake of the succeeding maize crop supplied with 40–45 kg N ha–1 and grown after 4 years of continuous sorghum cropping. It may therefore be concluded that nodulating soybean, lablab, green gram and black gram may be either intercropped or grown in rotation with cereals in order to economize the use of fertilizer N for maize production in the Nigerian savannah.

Effects of phosphorus fertilizer sources on cowpea and subsequent cereal crop productivity in semi-arid West Africa

A natural rock phosphate, ‘Kodjari” (RP), sparingly soluble, indigenous to Burkina Faso, and a commercial single superphosphate (SSP) fertilizer were studied at Farako-Bâ in the Northern Guinea Savannah (NGS) and at Oipasse in the Sudan Savannah (SS) regions of Burkina Faso. A 3-year crop sequence either of cowpea, maize and sorghum or of cowpea, sorghum and sorghum was used, respectively, in the NGS and SS regions. The sorghum crop in the third year was not fertilized with any phosphorus (P) source. The objectives of the research were to study the direct and residual effects of the P fertilizers on soil fertility improvement in order to boost agricultural productivity in both regions.Cowpea daylength-insensitive cultivars, in both regions, and maize and sorghum in the NGS and SS regions, respectively, responded more strongly to SSP than to RP fertilizer treatments. The optimum rate of SSP and RP source was 21·8 kg P/ha and 43·6 kg P/ha, respectively, for cowpea in both regions. The optimum rates of phosphorus fertilizer applied in the second year to maize in the NGS and to sorghum in the SS region, in addition to the optimum rate of P applied to cowpea the previous year, was 10·9 kg P/ha of SSP or 43·6 kg P/ha of RP, and 21·8 kg P/ha of SSP or 43·6 kg P/ha of RP, respectively. Both P sources had significant residual effects for up to 2 years. The agronomic effectiveness of RP relative to SSP, in the year of application of both fertilizers, was greater for cowpea than for maize in the NGS region and similar for cowpea and sorghum in the SS region; it increased markedly for the two subsequent cereal crops in both regions. Cowpea fertilization with both P sources proved, therefore, to be effective in improving the soil fertility and boosting the productivity of cereal crops in the 3-year crop sequence.

Serological survey of brucellosis in traditionally managed domestic fowl in northern Guinea savannah, Nigeria

A serological survey of brucellosis in traditionally managed local domestic fowl was carried out using the microtitre serum agglutination test with Brucella abortus antigen. Sixty two of 172 domestic fowl sampled (30%) were positive. Because most traditionally managed animals are not segregated, this indicates a potential source of infection to other livestock. Most of the birds identified as positive had titres of 1:40. The public health importance of the disease is highlighted and control measures suggested.

Descriptive epidemiology of lymphatic filariasis in Ghana

A national filariasis survey was conducted to determine the prevalence and distribution of Wuchereria bancrofti microfilaraemia and clinical disease associated with lymphatic filariasis in Ghana. Multi-stage systematic sampling was used to select households to be examined in all 10 administrative regions of the country. The results showed a high prevalence of microfilaraemia and disease with considerable regional variation in all the quantities investigated. In general, the disease was more prevalent in the northern guinea savannah and the southern coastal savannah, while the middle forest belt was relatively free. Even within the regions, there was considerable variation in the distribution of the disease. The disease is of potentially major public health significance, particularly in the northern and coastal savannahs, and requires the design and implementation of a control programme.

Tomato response to planting arrangement types during dry-hot seasons in the northern Guinea savannah of Nigeria

Two cultivars of tomato were used in trials conducted at Kadawa (Nigeria, 11° 39′N, 08° 02′E) to assess the benefits of three types of planting arrangements on tomato fruit set and yield during periods of high environmental temperature. Planting double sides of irrigation water lines of ridges (DWL) and planting in sunken beds (SB) were compared with the conventional planting along a single side of the irrigation water line (SWL). Fruit set per plant and marketable fruit yield under both DWL and SB were higher than under SWL. The marketable yield difference was statistically significant ( P = 0.05).

Infestation of maize and sorghum seeds by Sitophilus, Rhizopertha and Sitotroga in three contiguous climatic zones in Nigeria

Over a 9-month period, samples of maize and sorghum seeds were purchased monthly from markets located in three contiguous climatic zones of Nigeria; the grain samples were examined and insect pests found on them were recorded. Species of Sitophilus, Rhizopertha and Sitotroga accounted for 57–84% of all insect pests collected from the two grain types. Significantly more insect pests were recorded on grains obtained from the southern guinea savannah zone than from the northern guinea and sudan savannah zones. The relative incidence of the insect pests in the three zones is related to moisture availability reflected in grain moisture content.

Herbicide evaluation in millet in the northern Guinea and Sudan savannah of Nigeria

Abstract Millet is an important crop in the drier parts of Africa and Asia, but because it is not widely cultivated in most developed countries of the world, comparatively little research has been conducted with regard to chemical weed control. In 1980 and 1981, atrazine, terbuthylazine and propazine at 0.8 and 1.6 kg a.i./ha and their mixtures were evaluated on millet at two sites in Nigeria. The lower rate of 0.8 kg a.i./ha was either supplemented with one hoe weeding or remained unweeded. Herbicide treatments of 1.6 kg a.i./ha received no additional weeding. Although all rates of herbicide were well tolerated at the two locations in both years, the unweeded lower rates gave a lower grain yield due to weed competition. The weeded lower rates, however, gave yields which were not significantly different from the unweeded higher rates. Atrazine was found to be superior to either terbuthylazine or propazine in regard to weed control. The herbicide mixtures did not give any advantage over the other treatment...

Bwamba virus infection: A sero-survey of veterbrates in five ecological zones in Nigeria

Sera of humans, birds, domestic and wild animals from 28 localities in 5 ecological zones of Nigeria were tested for neutralizing antibody to Bwamba virus. A total of 984 human sera were tested, of which 516 (52·4%) were positive for Bwamba antibody. The highest prevalence (68·2%) was found in the southern guinea savannah zone. The prevalence in other zones were: 62·3% in derived savannah, 40·6% in swamp forest, and 32·1% in rain forest. The small number of samples tested from the Jos Plateau (northern guinea savannah zone) renders uninterpretable the high prevalence (74%) in this area. Significant differences in antibody prevalence were found between the relatively dry savannah areas (southern guinea and derived savannah) and the wet forested areas (swamp forest and rain forest). Except for a significantly lower prevalence of Bwamba antibody in urban dwellers in the wet forested zone as compared with rural dwellers, antibody prevalence was not significantly different for sites within each major ecologic zone. None of the 502 animal and bird sera tested was positive for Bwamba virus antibody. It is suggested that man is an important host in the transmission cycle of Bwamba virus and that Aedes (N.) circumluteolus is the major vector.

Sulphur in Northern Nigerian Soils: 1. The effects of cultivation and fertilizers on total S and sulphate patterns in soil profiles

SUMMARYOrganic-S and sulphate-S were measured in the Northern Guinea savannah zone down soil profiles under undisturbed natural vegetation, and in land cleared and cropped, with and without fertilizers and farmyard manure. The main soil type was a drained, red to red-brown, sandy clay to clay loam (pH 4·1–5·6 in 0·01 M-Cal2), which strongly sorbed sulphate.Organic-S was most in the surface layers and decreased with depth. Root remains from the natural fallow vegetation, present up to 9 years after clearance, strongly influenced the distribution of organic-S. The roots disappeared after 19 years, when distribution of organic-S mainly reflected crop-root distribution; amounts of organic-S were related to crop yields. FYM was less effective in maintaining organic-S than fertilizers containing P and N.Profiles under natural vegetation contained little sulphate-S but it accumulated in the sub-soil after clearance when S was not removed. The sulphate pattern of profiles under unfertilized crops resembled that under natural vegetation. All fertilized sites had a well-defined sulphate sorbtion pattern, the deepest maximum was at 50 cm on a plot where more than 800 kg S/ha had been applied in nineteen annual aounts. Sulphate-S ranged from &gt; 1 ppm, in the deepest samples, to 52 ppm at the absorption maximum.Almost all the sulphur applied was in the profiles or removed in harvested crops, showing that losses from erosion and leaching were small.

A HIGH INCIDENCE OF DIELDRIN-RESISTANCE IN ANOPHELES GAMBIAE GILES FROM AN UNSPRAYED AREA IN NORTHERN NIGERIA.

IN the course of recent investigations in the northern Guinea savannah of Nigeria on the ecology1 of Anopheles gambiae Giles and A. funestus Giles and on their behaviour in huts sprayed with insecticides2, determinations were made of the susceptibility of both species to DDT and to dieldrin in a area near the town of Kaduna. Apart from very small-scale trials in which a total of 8 village huts were sprayed with DDT and a mixture of DDT and malathion, and apart from the fairly regular use of DDT (but not dieldrin or BHC) as a larvicide on streams in the township of Kaduna, the whole of the northern Guinea savannah can be considered an unsprayed area. The nearest area receiving regular insecticidal house-spraying is the Western Sokoto area, about 200 miles north-west, where DDT has been used since 1957. Prior to this both BHC and dieldrin had been used and dieldrin-resistance in A. gambiae shown to be prevalent from 19553. Dieldrin-resistance was also found in A. gambiae in 19564 in the township of Kano, some 150 miles north-east of Kaduna, and was attributed to the use of BHC mainly for agricultural purposes.

Field Trials of the Control of Glossina palpalis (R.-D.) by Obstructive Clearing

Two field trials of obstruction (‘ obstructive clearing ’) as a means of control of Glossina palpalis (R.-D.) in locations representative of the Northern and Southern Guinea Savannah zones of Nigeria, are described.In neither case was complete eradication achieved, pockets of G. palpalis remaining from the beginning at certain points on the main stream. Greater success was obtained in the smaller tributaries, which lent themselves more to obstruction. There was little penetration of G. palpalis for any great distance into obstructed reaches from natural ‘ reservoirs ’ left abutting on to the obstruction, but a trial of the ‘ protective ’ value of obstruction failed, owing to complete penetration in some strength of 300 yd. of obstructed stream on either side of the point to be protected. In neither case was immigration of flies from elsewhere into the trial areas an important factor. Although, at first, the surviving fly population was very localised, there were later indications that dispersal was beginning to take place.Some accidents which may happen to obstruction are described, with their effects on its ultimate appearance. Consequent to these, a number of factors which limit the wide application of obstruction are stated. The more important of these are: the dimensions of the river-bed, which may be too large to permit of successful obstruction; the presence of wide swampy forest through which G. palpalis ranges freely; alternatively, the presence of shallow rocky stretches with low eroded banks that may be devoid of all but certain characteristic trees, where adequate obstruction is impossible; the rate of run-off of water in the catchment area, rapid run-off leading to spates which disrupt the obstruction; human interference with the obstruction in quest of firewood.No technical difficulties were encountered in carrying out obstruction, and costs were from 40 to 50 per cent, cheaper than comparable partial clearing.Considering the subsequent appearance of originally obstructed stream, and its frequent resemblance to partial clearing, the suggestion of ‘ destructive ’ clearing is put forward, in which the top canopy would be destroyed, but no effort made either to create obstruction or to clear away the fallen trees. Instead, reliance would be placed on the action of the various agencies encountered in these trials, which brought about the disruption of the obstruction, to produce the desired end-result.It is concluded that successful obstruction depends too much on specialised conditions, difficult to fulfil in large-scale tsetse control schemes, and that it is unlikely to become a normal method of control of G. palpalis in the savannah zones of Nigeria.