Twenty Years' Results from a Shade and Fertilizer Trial on Amazon Cocoa (<i>Theobroma cacao</i>) in Ghana

Ahenkorah, Y.; Halm, B. J.; Appiah, M. R.; Akrofi, G. S.; Yirenkyi, J. E. K.

doi:10.1017/s0014479700003380

Cited by 36 publications

(27 citation statements)

References 8 publications

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“…Cunningham and Arnold (1962) argued that 'heavy shade is one of the greatest growth-limiting factors and the most vigorous growth and highest yields are only possible without shade ' (p. 220). Later, research by Ahenkorah et al, (1987) found that mean yield of heavily shaded cocoa (Amelonado) was approximately half that of no-shade cocoa, whilst the yield from a medium shade system was intermediate. Despite the economic gains that can be derived from increased yields, results from the fertilizer-shade trials also document numerous deleterious effects that offset the positive gains when eliminating shade over time.…”

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confidence: 99%

Influences of Shading and Fertilization on on-Farm Yields of Cocoa in Ghana

Asare

Asante

et al. 2016

Ex. Agric.

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SUMMARYMost cocoa farms in Ghana are cultivated in complex agroforest systems, with plant growth and cocoa productivity being affected. The objective of this study was to investigate how shade trees affect cocoa yield, temperature and soil nutrients in low-input cocoa systems. Establishing plots on 24 farms in four locations (districts) in Ghana, we assessed the influence of varying canopy cover and fertilization on cocoa yields. Results showed no relationship between canopy cover and cocoa yields in the light crop season (February to August). For the main crop season (September to January), there was an interaction between shade and yields: Yields were higher on no-shade plots than on shaded plots in two districts, whilst there were no differences at the two other districts possibly due to differences in precipitation and soil nutrient status. On the other hand, there was a positive effect of increased canopy cover on yields within the shaded plots. Soil nutrient analyses revealed no significant differences between shaded and no-shade plots and adequate levels of N, K + , Fe 2+ , Cu 2+ and Zn 2+ were recorded. However, soil contents of P, C, Mg 2+ and Ca 2+ were below recommended values. Peak temperatures recorded in the cocoa canopies were above the recommended range for this species. Although shade trees had a slight modifying effect on peak temperatures, the magnitude appeared too small to have any practical effects.

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Influences of Shading and Fertilization on on-Farm Yields of Cocoa in Ghana

Asare

Asante

et al. 2016

Ex. Agric.

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“…However, the cacao can tolerate full sunlight and produce more pods than under shade [58]. Under fundamental cultural practices, increased in crop density, aeration, and sunlight penetration seed production are enhanced [59,60]. Moderate shade hardly affects bean yield, compared to heavy shading (>60%) which reduces yields by 30% [61].…”

Section: Shadementioning

confidence: 99%

The Ecophysiology of Abiotic and Biotic Stress on the Pollination and Fertilization of Cacao (Theobroma cacaoL.; formerly Sterculiaceae family)

Bridgemohan¹,

Mohammed²

2019

Abiotic and Biotic Stress in Plants

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The cocoa crop growth is highly influenced by environmental conditions, viz. temperature, which influence the phenological stages of flowering, fruiting, and pod growth. The plant produces caulescent flowers that are hermaphrodite and pollinated by insects, mainly Forcipomyia sp. (Diptera: Ceratopogonidae), but flowers setting to pods are very low. The efficiency of pollination depends on the degree of pollen compatibility and the number of pollen grains deposited on the stigma. It is assumed that midge population can be a limiting factor in the pollination of cocoa in addition to the environmental conditions. However, populations of insect pollinators are often severely disturbed by hurricanes through flooding of essential habitat and the widespread loss of existing flowers. This chapter will explore the role of midges [biotic] and the effect of climate [abiotic] variables. Understanding these ecological dynamics can lead to ways of conserving midge populations, mitigating the effects of global climate change and extreme climatic events. 2 1.1 Cacao stress Cacao cultivation is challenged by multiple abiotic and biotic stress factors [5], as they sessile to physical environment interactions with pest and pathogens [6], evapotranspiration [7], soil salinization [8], and climate change [9]. They developed a multitude of defence mechanisms to adapt and survive stress conditions [10] and harmful microorganisms [11]. Cacao agroecologyThe agroecological zones [AEZ] relate to soil fertility cycling and weed, pest, and watershed management. The cacao crop growth is specific to the AEZ, viz. temperature [12], flooding [13], and water stress [14]. The bimodal seasons influence the phenological stages of flowering, fruiting, and pod growth [15]. Water stress inhibits leaf development and pod setting and induces leaf abscission and photosynthetic rate (PR) [16]. Scope of stress pollination and fertilizationThe ecophysiology of abiotic and biotic stress on the pollination and fertilization of cacao is specific to four (4) main stages in the crop reproductive cycle, viz. prepollination, pollination fertilization, and postfertilization. This treatise processes from pollen germination to ovary fusion to the young pod development or cherelle [4].The scope of the treatise is limited to the author's research and critical review of the biotic or the internal factors that influence flower and fruit set in cacao. The abiotic factors are light intensity, relative humidity (RH), flooding, water stress, and cultural practices as shade, intercropping, and crop nutrition. The resilience of the pollinator to adapt to climatic changes and crop residue manipulation to increase the population dynamics of the cacao midges is examined, as well as advances in the area of olfactory sensitivity and cacao pollen odour [17]. Botany Vegetative stageCacao can be propagated by seedling, cuttings, or terminal grafts, reach maturity at 12-18 months [4], and develop juvenile vertical shoot which produces lateral branches or "jorquette/chupons". It is an ...

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“…In cacao (Theobroma cacao L.), monocultures are commonly implemented to maximize yields during the first 15 years of cultivation. Yet, as trees age beyond 15-20 years, cacao yields decrease due to depleted soils, physiological stress, as well as pest and disease pressure, which often results in the abandonment of plantations and the spread of the agricultural frontier into remaining forests (Ahenkorah et al, 1987;Clough et al, 2009;Foley et al, 2005;Tscharntke et al, 2011). While the overaged tree stocks on old plantations can be rehabilitated by implementing different measures, problems such as declining soil fertility, farmer poverty and climate change adaptation call for the diversification of plantations through the establishment of agroforestry (Jaimez et al, 2013;Schroth et al, 2016;Somarriba and Beer, 2011).…”

Section: Introductionmentioning

confidence: 99%

Effects of rehabilitation pruning and agroforestry on cacao tree development and yield in an older full-sun plantation

et al. 2019

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Overaged full-sun cacao plantations and the need for sustainable production systems call for combining rehabilitation of plantations with the establishment of agroforestry. We tested the effect of drastic rehabilitation pruning of old cacao tree stock and the introduction of both high- and low-diversity agroforestry on survival, growth and yield of T. cacao in a commercial plantation in peninsular Malaysia over a period of 5 years. We further determined the incidence of pests and diseases of cacao pods and assessed the performance of the whole system for smallholder farmers, including yields of by-crops. Rehabilitation pruning negatively affected cacao tree development and short-term yield. No more effects of pruning on cacao yield were observed starting in the third year on in the monoculture and starting in the fourth year on in low-diversity agroforestry. We found similar cacao tree development and yield in the low-diversity agroforestry and a common practice monoculture, suggesting that the implementation of agroforestry is a commercially feasible strategy, due to additional income generated through timber production. Reduced cacao tree development and yield in the high-diversity agroforestry were compensated by additional harvests of cassava and banana compared to monoculture. Incidence of cocoa pod borer (Conopomorpha cramerella) was lower in the agroforestry systems, especially the high-diversity system, while the incidence of black pod disease (Phytophthora spp.) did not differ between agroforestry and monoculture. The findings highlight the potential of agroforestry to reconcile ecologically sustainable land use with natural, cost-effective pest management. While pruning needs to be done with timing and disease pressure in mind to minimize short-term yield losses, this measure proved to be a feasible strategy for establishing agroforestry on extant plantations.

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Twenty Years' Results from a Shade and Fertilizer Trial on Amazon Cocoa (Theobroma cacao) in Ghana

Cited by 36 publications

References 8 publications

Influences of Shading and Fertilization on on-Farm Yields of Cocoa in Ghana

Influences of Shading and Fertilization on on-Farm Yields of Cocoa in Ghana

The Ecophysiology of Abiotic and Biotic Stress on the Pollination and Fertilization of Cacao (Theobroma cacaoL.; formerly Sterculiaceae family)

Effects of rehabilitation pruning and agroforestry on cacao tree development and yield in an older full-sun plantation

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