Coffee-based Agroforestry Research Articles

Editorial

The Africa Platform of the Ghent University Association and its journal Afrika Focus have always tried to focus on academic expertise in Africa and on academic north-south collaboration. Through its annual conference and its journal the Africa Platform offers a forum in which African academics and northern scholars working on Africa can forge new and often interdisciplinary collaboration. Most of this research on Africa is highly relevant to the development of African societies, as became clear at the last symposium of 1 This editorial was written just a few days before Nelson Mandela passed away on 5 December 2013. We have lost a great man. Hamba Kahle Madiba. [5 ] the Africa Platform, entitled ‘Africa: (post-development)?’ This special issue of Afrika Focus contains a number of articles that were presented at that symposium, which took place on 7 December 2012. In his article ‘Performance, poverty and urban development: Kigali’s motari and the special city’ Rollason describes the con ict between motorcycle taxis in Kigali and the city authorities. Urban development of Kigali is at stake here as these motari do not seem to match the image of the city the government wants to present. The article by Debusscher ‘Gender equality in European Union development policy: incorporating women’s voices or con rming hierarchies?’ is highly critical of the gender mainstreaming approach of the EU in its development aid towards sub-Saharan Africa. The EU seems to be more con- cerned with reaching its policy goals rather than challenging existing power structures in Africa. Both of these articles raise awareness on the level of a particular development-re- lated issue, and they have the potential to lead to concrete recommendations for national or EU development policies. The three remaining articles in this issue do not t in with the development-topic. Mulamba’s article ‘Luba folklore and women’s ethno-gendered discourse of wifehood in “Cintu Wa Bujitu”’, throws light on the socialization function of the Lubà folk song, a folkloric tradition that seems to perpetuate gender inequalities. Naphulo’s linguistic article (‘Teacher and learner beliefs and expectations about English language teaching at a Mozambican university’) critically analyses English language teaching in tertiary in- stitutions. The conclusion is that cultural backgrounds and beliefs need to be considered in order to enable effective teaching. The nal article of this issue (‘Arbuscular mycorrhizal fungi associated with shade trees and Coffea arabica L. in a coffee-based agroforestry system in Bonga, Southwestern Ethiopia’) examines coffee production and describes how a certain type of fungi could be used as a (natural) alternative to chemical fertilizers, so as to enhance coffee production in the forest areas of Ethiopia. All three of these articles indicate that traditional knowledge – be it linguistic, cultural or botanic – always plays an important role when trying to gain insight into African societies or when trying to improve practices and policies related to education, health care or agriculture. This is an idea that should as a mat- ter of course be a consideration when designing research in an African context. We like to remind the reader that in addition to fully- edged articles, Afrika Focus also publishes reports of doctoral research or eld work. In this issue we offer you four reports of PhDs defended at Ghent University. All four of these PhD degress were ob- tained by African scholars, thus testifying to the vibrant research collaboration that exists between African institutions and this Western European university. These current reports belong to the domains of Biology and Marine Biology, Linguistics and Health Care.

Combining a typology and a conceptual model of cropping system to explore the diversity of relationships between ecosystem services: The case of erosion control in coffee-based agroforestry systems in Costa Rica

With increasing pressure on farmers to improve the performance of their cropping systems, there is a growing need to design cropping systems that respond concurrently to environmental, agronomic and socioeconomic constraints. However, the trade-offs between ecosystem services, including provisioning services, can vary considerably from plot to plot. Using a typology of agricultural practices to adapt a conceptual model of the cropping system can provide an instrument to support the design of cropping systems that take into account the diversity of environmental and socioeconomic conditions and trade-offs within a study site. This method was tested to design coffee-based agroforestry systems mitigating soil erosion in central Costa Rica, a case study with a high-value crop in a complex relationship to its biophysical environment. A generic plot-scale conceptual model representing the effect of agricultural practices and environmental factors was designed, with erosion reduction, coffee production and gross margin as the outputs. Quantitative data on agricultural practices and costs were then collected over two years on a sample of plots in an 18km2 watershed upstream of a hydroelectric dam. A typology of these plots was built based on agricultural management practices; the resulting groups were further characterized by socioeconomic and environmental variables. The critical variables from each group of plots were used to adapt the conceptual model to the groups from the typology. The four groups found were (1) low-intensity management; (2) intensive management; (3) shaded agroecosystem, and (4) intensive agrochemical management. The conceptual model helped analyze the key processes and trade-offs for each group and helped make recommendations of adapted erosion control practices. The model showed that for some groups, less time-consuming erosion control actions not impacting coffee production might be more suitable, such as drainage canals, terraces, and vegetative barriers. In contrast, other groups had better socioeconomic or environmental conditions that opened the possibility of using shade trees or manual weed control (as opposed to herbicide use) to control erosion.This method finds its application in the plot-scale design and prototyping of agricultural systems that better respond to specific constraints, and can provide more relevant basis for discussion with farmers in participative methods. It also presents the advantage of requiring little data acquisition, although it can be further developed through integrating numerical relationships for quantitative modeling.

Arbuscular mycorrhizal fungi associated with shade trees and Coffea arabica L. in a coffee-based agroforestry system in Bonga, Southwestern Ethiopia

In a first step to understand the interactions between Colfea arabica L. trees and mycorrhizae in Ethiopia, an investigation of the current mycorrhizal colonization status of roots was undertaken. We sampled 14 shade tree species occurring in coffee populations in Bonga forest, Ethiopia. Milletia ferruginea, Schefflera abyssinica, Croton macrostachyus, Ficus vasta, F. sur, Albizia gummifera, Olea capensis, Cordia africana, Ehretia abyssinica, Pouteria adolfi-friederici, Pavetta oliveriana, Prunus africana, Phoenix reclinata and Polyscias fulva. Coffee trees sampled under each shade tree were all shown to be colonized by arbuscular mycorrhizal fungi (AM fungi). Four genera and 9 different species of AM fungi were found in the soils. Glomus (Sp1, Sp2, & Sp3 & Sp4), Scutellospora (Sp1 & Sp2) and Gigaspora (Sp1 & Sp2) were found under all 14 shade tree species, whereas Acaulospora (Sp1) occurred only in slightly acidic soils, within a pH range of 4.93-5.75. Generally, roots of the coffee trees were colonized by arbuscules to a greater degree than those of their shade trees, the arbuscular colonization percentage (AC%) of the former being higher than the latter (significant difference at 0.05 level). Though differences were not statistically significant, the overall hyphal colonization percentage (HC%) and mycorrhizal hyphal colonization percentage (MHC%) were shown to be slightly higher under coffee trees than under their shade trees. However, the differences were statistically significant at 0.05 level in the case of HC% values of coffee trees under Pouteria adolf-friederici and MHC% under Cordia africana. Spore density and all types of proportional root colonization parameters (HC%, MHC%, AC% and vesicular colonization percentage, VC%) for both coffee and shade trees were negatively and significantly correlated with organic soil carbon, total N, available P, EC and Zn. Correlation between arbuscular colonization for coffee (AC%) and organic carbon was not significantly positive at a 0.05 level. Incidence of specific spore morphotypes was also correlated with physical and chemical soil properties. Results indicate that AM fungi could potentially be important in aforestation and help to promote coffee production activities in Ethiopia providing an alternative to expensive chemical fertilizer use, and would offer management methods that take advantage of natural systems dynamics that could potentially preserve and enhance coffee production.

ALMACÉN DE CARBONO EN SISTEMAS AGROFORESTALES CON CAFÉ

El presente estudio se realizó con el objetivo de estimar el almacén de carbono en sistemas agro¬forestales (SAF) con base en café en la región de Huatusco, zona de mayor producción de café (Coffea arabiga L.) en el estado de Veracruz, México, a fin de obtener información cuantitativa sobre el potencial de mitigación de carbono en los SAF de la región. Para ello, se estimaron los reservorios de carbono en biomasa vegetal y la materia orgánica edáfica existentes en sistemas agroforestales de café-plátano, café-macadamia, café-cedro rosado, café-ganado ovino y café-chalahuite, y como referencia de una condición no agroforestal se incluyeron un bosque primario y un potrero con prade¬ra natural. La recolección de muestras se hizo en parcelas de 4 x 25 m (100 m2), donde se colectó biomasa de vegetación herbácea y mantillo, y para el suelo la profundidad de muestreo fue de 0 a 30 cm. El sistema agroforestal que presentó la mayor cantidad de carbono aéreo, estimado con modelos alelométricos, fue café-cedro rosado (Ca + Ce), con 114 Mg C•ha-1, seguido de los sistemas café - macadamia (Ca + Ma), con 34 Mg C•ha-1; café-chalahuite (Ca + Ch), con 29 Mg C•ha-1; café-plátano velillo (Ca + Pl), con 27 Mg C•ha-1; y por último el sistema silvopastoril (Sp), con 2 Mg C•ha-1. Para el caso del carbono orgánico del suelo, el tratamiento (Ca + Ce) fue el que presentó mayor contenido de carbono fácilmente oxidable en el suelo, con 58 Mg C•ha-1, y el menor fue el tratamiento potrero (P), con 50 Mg C•ha-1. Del carbono orgánico total entre los SAF el tratamiento Ca + Ce fue el que tuvo el mayor valor, con 172 Mg C•ha-1, y el tratamiento silvopastoril (Sp) presentó el menor, con 65 Mg C•ha-1. De los sistemas evaluados se concluye que, en promedio, los SAF almacenan 102 Mg C•ha-1, mientras que el potrero almacena 52 t C•ha-1, y el bosque primario es el sistema que más almacena carbono total, con un valor de 355 Mg C•ha-1.

Performance of Coffea arabica F1 hybrids in agroforestry and full-sun cropping systems in comparison with American pure line cultivars

Coffea arabica F1 hybrids derived from crosses between wild Sudan-Ethiopian and American cultivars and propagated by somatic embryogenesis have been obtained in Central America. These new hybrids considerably enhanced the genetic diversity of coffee in the region. We conducted 15 trials to assess whether using hybrids represents substantial genetic progress in terms of productivity in agroforestry and full-sun cropping systems. The new germplasm was grown in the same conditions as the best American cultivar (homozygous pure lines). The results showed that yields of hybrids were earlier and superior to those of American cultivars. The hybrids were also more stable than the American cultivars in all environments. In the agroforestry system, the mean yield of hybrids was 58% higher than that of the American cultivars, while the mean yield of hybrids in the full-sun system was 34% higher. Coffee-based agroforestry systems (AS) are considered effective in protecting the environment in the volcanic cordilleras of Central America. We found that introducing hybrids in coffee-based AS can considerably increase productivity. This finding could be a convincing argument to encourage coffee growers who have adopted the full-sun cropping system to return to agroforestry cropping systems. Finally, the conditions for large-scale dissemination of those new hybrids—which represent a major innovation for C. arabica cropping—was analysed.

Poverty and Environmental Services: Case Study in Way Besai Watershed, Lampung Province, Indonesia

Suyanto, S., N. Khususiyah, and B. Leimona. 2007. Poverty and environmental services: case study in Way Besai watershed, Lampung Province, Indonesia. Ecology and Society 12(2): 13. https://doi.org/10.5751/ES-02070-120213

Litter layer residence time in forest and coffee agroforestry systems in Sumberjaya, West Lampung

Forest conversion to coffee-based agroforestry leads to sudden disappearance of the litter layer and a decrease in the rate of litter fall, reducing food for ecosystem engineers such as earthworms. With time, however, a new litter layer is created potentially returning to forest-like conditions at the soil surface. This research quantified litter thickness, earthworm populations and soil macroporosity in response to land use change in the Sumberjaya benchmark area (West Lampung, Indonesia) by comparing: (a) remnant forest (control); (b) multistrata shaded coffee with fruit and timber trees, as well as nitrogen-fixing shade trees; (c) shaded coffee (nitrogen-fixing shade trees, but less than five tree species per plot); and (d) sun coffee (‘monoculture’) with coffee forming more than 80% of total stem basal area. Plots were selected with tree ages of 7–10 years in three slope classes: (a) flat (0–10°); (b) medium (10–30°); and (c) steep (>30°). The mean standing necromass was 6.1, 4.5, 3.8 and 3.0 Mg ha −1 for forest, multistrata, shade coffee and sun coffee, respectively, without significant influences of slope. Fine, partly decomposed litter was 33–40% of total necromass, coarse leaf litter 14–16%, and twigs and branches comprised the remaining 43–52%. Soil organic carbon content (C org) was highest in the forest. The largest annual litter input was found in the remnant forest (14 Mg ha −1 year −1), followed by multistrata, shaded and monoculture coffee systems, i.e., 9.8, 6.6 and 4.0 Mg ha −1 year −1, respectively. The population density of earthworms in the forest was 50% lower than in multistrata coffee gardens (150 individuals m −2), but its biomass (31 g m −2) was twice that in the multistrata coffee gardens. The lowest population density of earthworms was found in the shade coffee system (150 individuals m −2) with a biomass of 7 g m −2. A simple model suggests that the standing litter in the various land use systems is consistent with measured litter inputs and decay rates, but that the soil organic matter (SOM) content and macroporosity of the shade and multistrata systems are less than predicted. The recovery of a surface litter layer in sun coffee systems can provide protection from erosion with time, but will not be sufficient to restore macroporosity at the level of forest soils, leading to hydrologic alterations that favor overland flow.