Savanna Zone Of Nigeria Research Articles

Impact of grazing on soil in the southern guinea savanna zone of Nigeria

This study examines the effects of traditional sedentary grazing on soils in the southern guinea savanna ecosystem in Nigeria. The characteristics of soil in grazed plots are compared with those of similar soil in ungrazed plots in a savanna ‘forest’ reserve in a nearby locality, in order to infer the effects of grazing. In the 0–10 cm layer of the soil, organic carbon, total nitrogen, exchangeable calcium, magnesium, potassium, sodium, cation exchange capacity and available phosphorus levels are significantly lower in the grazed plots. Decline in the organic carbon and nutrient levels of the grazed plots is mainly due to soil exposure resulting from grazing and savanna burning and the attendant processes of accelerated organic matter decomposition and nutrient loss through leaching and erosion. Low soil nutrient levels in the grazed plots will reduce primary production and hence the rate of herbage production for livestock. It could also lead to some adverse ecological changes in the ecosystem with the disappearance of certain plant species. The ecosystem consequently becomes less diverse and resilient as soil nutrient status becomes increasingly impoverished. It is suggested that herdsmen should practise rotational grazing and that livestock should be fed with a supplementary fodder of legumes, such as Gliricidia sepiumand Leucaena leucocephalaplanted in natural grazing areas, in order to minimise the problems of overgrazing which are frequently experienced during the dry season.

Pasture floristic composition in different Eucalyptus species plantations in some parts of northern Guinea savanna zone of Nigeria

In view of the recurrent drought and human population pressures which have drastically reduced the density of pasture species within the Nigerian savannas, the nomadic herdsmen rely mostly on silvipastoralism, grazing their herds in Eucalyptus plantations. In this study, the population of understorey forage and non-forage speicies and the relative light intensities on the forest floors of two Eucalyptus species, viz: E. citridodora, and E. camaldŭlensis were compared with those of open savanna lands at Kabama, Samaru and Guga, all within the Northern Guinea savanna zone.

Effects of farming practices on populations of two grasshopper pests(Kraussaria angulifraKrauss andOedaleus senegalensisKrauss (Orthoptera: Acrididae) in Northern Nigeria

Abstract The effects of farming practices, continuous cropping, fallowing, cattle grazing and afforestation on the populations of two grasshopper pests, namely, Kraussaria angulifera and Oedaleus senegalensis were investigatged at Gumel, in the savanna zone of Nigeria. The populations of the adults and the nymphs of the grasshopper species were assessed by flushing quadrats in eight habitats. The Azadirachta indica (neem) plantation and the cropped fields of millet (Pennisetum americanum) surghum (Sorghum bicolor) and sorghum intercropped with Benniseed (Sesamum indicum) had lower populations of grasshoppers than the grazing field, fallow lands and Acacia arabica plantation. Intensification of fallow resulted in an increase in grasshopper numbers. Trampling by cattle did not significantly affect the viability of grasshopper eggs in the fields. Cultivation and afforestation affected grasshoppers adversely. K. angulifera was more vulnerable to cultivation pressure than O. senegalensis.

Direct and residual effect of liming on yield and nutrient uptake of maize (Zea mays L.) in moderately acid soils in the savanna zone of Nigeria

Field experiments were conducted during wet season of 1980, 1981 and 1982 to determine the direct and residual effect of liming on yield and nutrient uptake of maize in moderately acid soils (pH -H2O; 5.0–5.4) at three locations viz Kontagora, Tumu and Yandev in the savanna zone of Nigeria. Maize crop was grown at five lime rates 0, 0.5, 1.0, 2.0 and 4.0 t ha−1 and two N sources (calcium ammonium nitrate and urea). Liming at a rate of 2 t ha−1 maintained high maize yield for three years after application at Kontagora and Yandev. At Tumu 1 t ha−1 was sufficient to get high yield of maize for three years. Higher rates of lime significantly depressed yield. Uptake of N, P and K was increased significantly with lime application upto 2 t ha−1 lime at Kontagora and Yandev but at Tumu it increased only upto 1 t ha−1. The response of P uptake to liming was higher in comparison to N and K uptake. Calcium and magnesium uptake responded upto 4 t ha−1 lime at Kontagora & Yandev and upto 2 t ha−1 at Tumu. The residual effect of liming lasted longer than 2 years. High lime rates reduced maize yields and crop nutrient uptake.

The development of Dysdercus voelkeri on three new sorghum varieties and assessment of its damage to grains

The development of Dysdercus voelkeri on three dwarf and short-season varieties of sorghum: BES, HP3 and HP8 and its damage to the grains were studied in the laboratory and greenhouse, respectively. An average development period of 27 days was recorded on the three varieties. The fecundity, fertility, live-weight and dorsal surface area were significantly higher in insects that developed on HP8 than in those that developed on BES and HP3. There were, however, no significant differences in these parameters except fertility between the insects that developed on BES and HP3. The highest grain damage of 56.6% was recorded for HP8, while 51 and 27.6% grain damage were recorded for BES and HP3, respectively. The potential pest status of D. voelkeri on these new and improved sorghum varieties in the southern Guinea and derived savanna zones of Nigeria is confirmed in these studies. Effective control of this bug and other sucking insects at the milky stage of grains' development is suggested for high yield and good quality grains.

Impact on soils of plantations of Pinus caribaea stands in natural tropical savannas

Soil properties to a depth of 90 cm under stands of 14-year-old Pinus caribaea var. hondurensis and adjacent natural savanna forest cover were compared in the savanna zone of Nigeria. No significant differences in soil physical characteristics were noted except modest increases in top soil bulk density values under the pine. But soil chemical properties, viz. organic carbon, total N, extractable P and exchangeable K, Ca and Mg showed statistically significant decline in the upper 10 cm of the mineral soil as a result of reafforestation with P. caribaea. Soil changes in relation to planation age were also discussed.

Effect of Iron on Maize Yields in Forest and Savanna Zones of Nigeria

SUMMARYThe results of a two year field study to determine the effect of iron on the yield of maize in the forest and savanna zones of Nigeria have indicated that new and old fields in the savanna, and old fields in the forest zone, require additional iron. The optimum iron requirement for maize in both zones is 3 kg ha−1.

Effects of Sett Size and Spacing on Tuber Yield of White Guinea Yam (Dioscorea rotundata) in the Rainforest and Savanna Zones of Nigeria

SUMMARYField studies designed to investigate the effects of sett size and spacing on tuber yield of white Guinea yam were conducted in three locations over a two year period in the rainforest and savanna zones of Nigeria. Sett weights larger than 400 g could be used for maximum tuber yields in both forest and savanna zones. Spacing had no significant effects on tuber yield in the savanna zone, but optimum spacing has yet to be identified in the forest zone.

Field evaluation of some new ultra‐low‐volume (u.l.v.) insecticides for rainfed cotton in the Niger State of Nigeria

Abstract Field trials were conducted at Kontagora and Mokwa in the Guinea savanna zone of Nigeria to evaluate the relative efficiency of u.l.v. formulations of insecticides and conventional spraying methods for improving cotton yield. Endosulfan and monocrotophos were applied at the rate of 3 //ha using a battery‐operated Ulva micron sprayer. Monocrotophos gave an increased cotton yield of 938.5 and 1235.5 kg seed cotton/ha in the 1975–76 and 1976–77 seasons, respectively, when compared with controls. In the same way, endosulfan gave increased yields of 670.0 and 714.5 kg/ha. Carbaryl, applied at the rate of 1.1 kg w.p./ha using a knapsack sprayer, resulted in increased yields of 587.0 and 763.5 kg/ha, respectively. it is concluded that monocrotophos u.l.v. is the most effective insecticide, and that spraying is a prerequisite for an economical cotton crop.

Weed Control in Pearl Millet in the Savanna Zone of Nigeria

Abstract Herbicides were evaluated for selective weed control in pearl millet in field trials conducted in the Sudan and the Northern Guinea zones of Nigeria from 1977 to 1979. Some of the herbicide treatments had a supplementary weeding, during the two later years of the study. The work was extended to the Southern Guinea zone in 1979. Propazine at 0.8 kg a.i./ha was the most tolerated herbicide on the loamy sand soils of the Sudan zone. It was tolerated up to 1.6 kg a.i./ha in the comparatively heavier sandy loam soils of the Guinea zones. Linuron was toxic to the crop at equivalent rates. Mixtures (1:1) of the two herbicides were better tolerated than linuron alone but did not show any advantage over propazine. The selectivity of terbuthylazine, used in one out of three years, was comparable in the Northern and Southern Guinea zones while it was less selective in the Sudan zone. Under severe weed infestation, one supplementary weeding following pre-emergence herbicides resulted in yields comparable to those obtained with two hoe-weedings. An average loss of 46% in grain yield was caused by unchecked weed growth.

Seasonal Changes in Bovine and Caprine Blood Chemistry and Hepatic Vitamin A in Savanna Zone of Nigeria

A seasonal survey was carried out in Kaduna and Kano Stales of Nigeria to determine the plasma levels of phosphorus, calcium and magnesium, and plasma and hepatic vitamin A levels of Bunaji (White Fulani) cows and the local brown goats. The significance of the results on the reproductive efficiency of the Bunaji cattle is discussed.

Contribution of organic matter and clay to the cation exchange capacity of soils in the savanna zone of Nigeria

Abstract The cation exchange capacities (CEC) of surface and subsurface soils of Afaka, Mokwa, Nimbia and Sanga River forest reserves in the savanna region of Nigeria were determined. The CEC was statistically partioned into organic matter and clay components using linear multiple regression analysis. Standard partial regression coefficients indicate that the cation exchange properties of the surface soils were mostly associated with organic matter. Between 50 and 83 per cent of the variation in the CEC values could be attributed to organic matter content. The exchange capacities of organic matter in the four reserves were calculated to be in the range 282 to 322 me/100g while those of clay were 7 to 18 me/100g. Except in Nimbia forest reserve, the contribution of clay to the CEC of surface soils was nonsignificant. In the subsoils both organic matter and clay made significant contributions to the CEC. Multiple correlation coefficients (R) of organic matter and clay with CEC in the subsoils were? 0.86, 0....

The Potassium Status of Soils in the Savanna Zone of Nigeria

SUMMARYThirty one soils from the Savanna Zone of Nigeria were low in exchangeable potassium, ΔK°, and ΔK°° and had very low potassium buffer capacities. The soils were low in clay, which was kaolinitic. Two soils high in 2:1 layer clay minerals contained higher quantities of labile potassium. Total potassium varied with parent material. Release of non-exchangeable potassium was low. After cropping, wet/dry cycles released exchangeable potassium. Potassium deficiency is expected to occur commonly with intensive cropping in the field.

Soil Fertility under Continuous Cultivation in Northern Nigeria

SUMMARYSoil acidity, incipient potassium deficiency, and a deficiency of one or more trace elements were limiting factors in three trials of long-term soil fertility changes under continuous cultivation in the Sudan Savanna zone of Nigeria. The effectiveness of organic manures is explained largely or wholly in terms of these factors, since no evidence has yet been found to suggest that the addition of organic matter as such is of value.