Savannah Ecological Zone Research Articles

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

Current Status and Future Potential of Roselle Production and Utilization in Nigeria

ABSTRACT Roselle (Hibiscus sabdariffa L.) is widely cultivated in the forest and savannah ecological zones of Nigeria. It has a lot of potential as an industrial crop. Smallholder and resource poor farmers grow it. Roselle is popularly grown for its fiber content and for its leaves, calyces, roots, seeds, which are used either for industrial, medical, commercial, or domestic uses. Its use as a fiber crop is yet to be exploited in Nigeria. This paper discusses the agronomy, utilization, and commercialization of the crop. Future research needs are also discussed.

Nitrogen and Weed Management in Maize Intercropped with Upland Rice

ABSTRACT A field experiment was conducted during the 1994 and 1995 wet seasons on the research farm of the Institute for Agricultural Research, Samaru (11°11'N, 0.7°E 680 m) located in the northern Guinea Savannah ecological zone of Nigeria. The experiment was laid out in split-plot design with three levels of nitrogen (0, 60 and 120 KgN/ha) in the main plot and ten periods of weed removal/infestation in the sub-plot. The productivity of both maize and rice was enhanced by increased application of nitrogen fertilizer in both years in all the plots that were kept weed free from the initial 6 weeks after sowing (WAS) up to harvest. Weed infestation for the initial 3 WAS enhanced the productivity of these crops. However, there was no significant response of nitrogen application in the plots that were kept weed-free for only the initial 3 WAS and those weeds infested throughout the crop cycle.

Socio-cultural Factors and Land Degradation in the South Tongu District of Ghana: Some Implications for Resource Protection and Environmental Health

South Tongu District, like most districts in the savannah ecological zone of Ghana, is planning to counteract its rapidly deteriorating catchment, on which it depends as a resource base for food supply, through the establishment of afforestation and other conservation programmes. This paper argues that a good understanding of socio-cultural factors would help shape the formulation and subsequent implementation of conservation programmes. It identifies and sheds light on how some key socio-cultural factors (notably tenure) promote deforestation and land degradation in South Tongu District. It further points out some implications of degradation for resource protection and environmental health, which need to be considered when formulating a catchment management plan. It concludes by identifying some possible policy measures as a way forward in promoting sustainable catchment management in the district.

A study of a texture-based equation for estimating the saturated hydraulic conductivity of an alfisol in the sudan savannah ecological zone, Ghana

Abstract Saturated hydraulic conductivities of Varempere series soils (plinthaqualf) located in the sudan savannah zone of Ghana were measured by the falling head method and compared with values estimated by the texture-based equation of Rawls et al. (1982). The comparisons indicated that saturated hydraulic conductivity values estimated using the texture-based equation could predict those measured within the same order of magnitude only for the coarse-textured soil. For the fine textured soils, the texture-based equation underestimated the measured values by approximately one order of magnitude. It was concluded that in modelling hydrological processes such as infiltration in coarse-textured soils, the use of the texture-based equation would be useful. However, for technical designs of irrigation and drainage systems that require more accurate information on saturated hydraulic conductivity, the use of the texture-based equation should be discouraged.