Browsing by Author "Van de Giesen, Nick"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Effects of charcoal production on maize yield, chemical properties and texture of soil
    (Biology and Fertility of soils (Springer-Verlag), 2004-03) Oguntunde, Philip G.; Fosu, Matthias; Ajayi, Ayodele E.; Van de Giesen, Nick
    The effects of charcoal production on soil textural and chemical properties were investigated in Ejura, Ghana. The aim was to study the effects of heating and charcoal residue on maize yield, soil texture and soil chemical properties. Composite samples were taken from the 0–10 cm layer of soil at charcoal-making sites and from adjacent fields (control). Twelve sites were randomly selected for the study across the range of the Kotokosu watershed. Maize was planted in four selected locations on charcoal site soils (CSS) and adjacent field soils (AFS) to assess the impact of charcoal production on crop yield. There was a significant increase in soil pH, base saturation, electrical conductivity, exchangeable Ca, Mg, K, Na and available P in the soil at the kiln sites as compared to the adjacent soils. A relative change of up to 329% was observed in K while organic C and total N decreased by 9.8% and 12.8%, respectively. Organic C and total N were highly correlated ( P <0.01) and both parameters significantly ( P <0.05) depended on clay minerals in the soils. Soil texture was also modified with a significantly higher sand content and lower clay fraction in the CSS. The grain and biomass yield of maize increased by 91% and 44%, respectively, on CSS as compared to AFS. Further research to ascertain the longterm effects of charcoal production on the soil environment and the fertility of tropical soils is needed. Keywords Charcoal production · Soil heating · Soil fertility · Maize yield · Ghana
  • Thumbnail Image
    Item
    Influence of Tree Age and Variety on Allometric Characteristics and Water Use of Mangifera indica L. Growing in Plantation
    (Hindawi Publishing Corporation, 2011-09-22) Oguntunde, Philip G.; Fasinmirin, Johnson T.; Van de Giesen, Nick
    Mango (Mangifera indica L.), a diffuse-porous species and one of the most important tropical tree crops [1], belongs to the family Anacardiaceae [2]. It is believed that mango was brought from Arabia to Africa in the first millennium AD [3]. Ghana received more than a dozen cultivars in the early 1920s and more than a dozen other cultivars were brought in later from Florida and India [2]. However, because of identification problems, an effort was initiated in 1967 to classify the seedlings in the Ejura district, the Ejura Agricultural Station, and the plantation of the Faculty of Agriculture, University of Science and Technology, Kumasi, in order to eliminate confusions and have identifiable cultivars marked for future research. There is great potential for the rapid growth of mango industry in West Africa if the current planting rate and government encouragements are sustained. Although mango is drought tolerant and could be conveniently cropped under rain-fed conditions, supplemental irrigation may be required for optimising growth, fruit set, and yield [4]. Poor and unreliable flowering is one of the factors leading to low productivity [5], but applying irrigation from peak flowering to fruit maturity could induce reliable flowering leading to high yield [6, 7]. Preflowering irrigation was reported to increase the overall photosynthetic activity of the tree at the time of flowering [8]. The necessity to directly and continuously monitor water use for precise irrigation scheduling in mango plantations has been reported [4, 7]. Subsequently, a Granier sap flow measurement method was evaluated and applied successfully to measure sap flow per unit sapwood area in young to mature mango trees. Despite current advances, especially in Australia, there is little or no information regarding water use of mango trees in West Africa. In the study area, the planting practices have resulted in age differences of adjacent plantations coupled with indiscriminate mixtures of varieties or cultivars. These lead to differences in cultivars composition on different stands. Previous studies reported that young/mature trees use more water per unit sapwood area than old trees of the same species in a similar environment due to changes in stem and branch hydraulics with age [9, 10] as well as pressure gradient due to gravity [11]. The objectives of this study were 2 Journal of Botany to examine the degree to which differences in tree age and variety mixture affect water use and allometric characteristics of mango trees under subhumid tropical environment of West Africa. The study was part of the just concluded GLOWA Volta project (http://www.glowa-volta.de/), which lasted between 2000 and 2009. In the context of this project, designed to study “sustainable water use under various land use change and rainfall reliability,” understanding the hydrological process in the basin water balance is very important. Determinations of water use from each component of ecosystem vegetation were required and therefore partly motivated this study