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Coffee agroecosystem performance under full sun, shade, conventional and organic management regimes in Central America

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Agroforest Syst (211) 82: DOI 1.17/s Coffee agroecosystem performance under full sun, shade, conventional and organic management regimes in Central America J. Haggar M. Barrios M. Bolaños
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Agroforest Syst (211) 82: DOI 1.17/s Coffee agroecosystem performance under full sun, shade, conventional and organic management regimes in Central America J. Haggar M. Barrios M. Bolaños M. Merlo P. Moraga R. Munguia A. Ponce S. Romero G. Soto C. Staver E. de M. F. Virginio Received: 3 April 21 / Accepted: 27 March 211 / Published online: 21 April 211 Ó Springer Science+Business Media B.V. 211 Abstract Changes in coffee economics are leading producers to reduce agrochemical use and increase the use of shade. Research is needed on how to balance the competition from shade trees with the provision of ecological services to the coffee. In 2, long-term coffee experiments were established in Costa Rica and Nicaragua to compare coffee agroecosystem J. Haggar M. Barrios Centro Agronómico Tropical de Investigación y Enseñanza, CATIE, Managua, Nicaragua M. Bolaños P. Moraga UNICAFE, Managua, Nicaragua M. Merlo S. Romero G. Soto E. de M. F. Virginio CATIE, Turrialba, Costa Rica R. Munguia Universidad Nacional Agrária, Managua, Nicaragua A. Ponce Instituto Nacional Tecnológica Agrária, Masatepe, Nicaragua C. Staver Bioversity, Montpellier, France J. Haggar (&) NRI, University of Greenwich, Chatham Maritime, Kent ME4 4TB, UK performance under full sun, legume and non-legume shade types, and intensive and moderate conventional and organic inputs. Coffee yield from intensive organic production was not significantly different from intensive conventional in Nicaragua, but in Costa Rica it was lower during three of the six harvests. Full sun coffee production over 6 years was greater than shaded coffee in Costa Rica (61.8 vs t ha -1, P =.2). In Nicaragua, full sun coffee production over 5 years (32.1 t ha -1 ) was equal to coffee with shade that included Tabebuia rosea (Bertol.) DC., (27 3 t ha -1 ) and both were more productive (P =.3) than coffee shaded with Inga laurina (Sw.) Willd. (21.6 t ha -1 ). Moderate input organic production was significantly lower than other managements under all shade types, except in the presence of Erythrina poepiggina (Walp.) O.F. Cook. Inga and Erythrina had greater basal area and nutrient recycling from prunings than other shade species. Intensive organic production increased soil ph and P, and had higher K compared to moderate conventional. Although legume shade trees potentially provide ecological services to associated coffee, this depends on management of the competition from those same trees. Keywords Erythrina poepiggiana Ecological services Inga laurina Nitrogen mineralization Nutrient balance Nutrient recycling Sustainable coffee production Tabebuia rosea Terminalia amazonia 286 Agroforest Syst (211) 82: Introduction In Central America, high-input or modern coffee production technology has achieved high yields for a select group of favoured producers who cultivate coffee in optimum growing conditions. This tripling or quadrupling in yields has been achieved by shortcutting ecological processes such as semi-closed nutrient cycles and food web diversity. These processes have been minimized or replaced by the use of petroleum-based fertilizers and pesticides with minimal use of a shade over-story or in full sun. For example, the benefits of a healthy soil built up from leaf litter under shade has been replaced by chemical inputs. Pesticides have replaced a buffered shade environment which helped keep pests at non-damaging levels (Guharay et al. 21). Efficient, organic nutrient cycles have been replaced by leaky inorganic fertilizer flows (Babar and Zak 1995). The high cost of purchased inputs coupled with the volatile prices for coffee has contributed to greater economic vulnerability of intensive coffee production, even for successful farmers (Siman 1992). In the full sun system, costs of production cannot easily be reduced, even when coffee prices are low, without substantial deterioration in yield potential in future years. Second, the model has not proven widely applicable for farm families with a small land base and limited resources. The majority of coffee-producers continue to harvest less than a tonne per hectare in most of Central America, only a third or less of potential yield (CEPAL 22). Third, the elimination or simplification of shade has generated concern for the loss of biodiversity (Perfecto et al. 1996). Finally, excessive pesticide and fertilizer use, soil erosion and inadequate coffee waste processing have contributed to pollution and environmental deterioration in fragile, yet vital, upper watersheds (Fernandez and Muschler 1999; Reynolds 1991). Coffee growers have begun to experiment with alternative production technologies to reduce costs, to access specialty markets, and to diversify income (e.g. Rice and Ward 1996). These include organic production often with leguminous shade trees which have traditionally been used in coffee (Beer et al. 1998; Lyngbæk et al. 21). Though, levels of productivity of organic producers are generally considerably lower than conventional producers (Lyngbæk et al. 21; Van der Vossen 25). Nevertheless, conventional farmers have also cut back on fertilizer and pesticide use to limit costs. Farmers also continue to look for economic diversification of the tree component with high value timber and fruit trees. To contribute to this search for more ecologically and economically sustainable coffee agroecosystems, CATIE and national partners in Costa Rica and Nicaragua established a long-term experiment of alternative coffee production systems with the following objectives (Haggar et al. 21; Virginio Filho et al. 22). 1. Identify the factors that determine the productive potential of coffee under intensive and moderate levels of organic inputs compared to conventional managements with similar levels of inputs. 2. Determine the effects of shade tree presence and composition, including the balance between the ecological services of nutrient cycling on soil fertility and shading on water stress, and competition for resources from the trees, on coffee production. 3. Through the interaction between shade types and organic and conventional management levels determine the tree characteristics that provide ecological services that may compensate lower levels of organic or conventional inputs. Knowledge of the degree to which ecological services from shade trees can replace use of external agrochemical inputs will enable farmers to design and manage coffee production systems that are economically more resilient, generate less environmental contamination, and provide more environmental services to society. Materials and methods Experimental design In 2 two experiments were established in different agroecological zones. Both experiments are situated in low altitude coffee growing areas (less than 8 m.a.s.l.) where the benefits of shade trees would be expected to be greatest, even though there is some full-sun coffee production. Turrialba, Costa Rica represents a low altitude (685 m.a.s.l.), wet coffee zone (3,2 mm annual rainfall) with no marked dry Agroforest Syst (211) 82: Table 1 Tree species used in shade combinations at two ecologically different sites Species (code) Phenology Canopy shape N-fixer Use Turrialba, Costa Rica Terminalia amazonia (J.F. Gmel.) Exell (TA) Evergreen High compact No Timber Chloroleucon eurycyclum Barneby & Grimes (CE) Evergreen High spreading Yes Timber Erythrina poepiggiana (Walp.) O.F. Cook (EP) Evergreen Low compact Yes Service Masatepe, Nicaragua Simarouba glauca DC. (SG) Evergreen High narrow No Timber Tabebuia rosea (Bertol.) DC. (TR) Deciduous High narrow No Timber Samanea saman (Jacq.) Merrill (SS) Evergreen High spreading Yes Timber Inga laurina (Sw.) Willd. (IL) Evergreen Low spreading Yes Service season. Masatepe, Nicaragua, is a low altitude (455 m.a.s.l.), dry coffee zone (1,47 mm annual rainfall) with a marked 6-month dry season (less than 5 mm per month). Main treatment plots are different shade tree combinations with subplots for input nutrient levels and pest management. At each site, different timber and service tree species were planted in accordance with those most commonly used by local farmers (Table 1). Trees were selected to represent legume service trees, legume timber trees, and non-legume timber trees with contrasting phenological or architectural characteristics. Each experiment has a full sun treatment and different combinations of the tree species to develop a gradient of nitrogen fixation and contrasting combinations of evergreen or deciduous shade and canopy type. Four input regimes have been implemented for nutrient, pest and weed management, under two levels of organic and two levels of conventional management (Table 2). The intensive conventional treatments use the complete technical package for maximizing productivity in full sun coffee including pesticides and herbicides. The moderate conventional management uses half the level of fertilization and management of pests according to certain criteria combined with cultural practices. Among the organic treatments the intensive organic applies chicken manure, minerals and pesticides, while the moderate organic only applies coffee waste and cultural management of pests. Organic and conventional fertilizer rates were altered over time depending on the whether the coffee was in its growth phase (first 2 years) or productive phase, and subsequently adjusted based on the results of soils analysis and changes in soil fertility. From years two to six (21 25) the moderate organic treatment in Costa Rica received the same fertilizer levels as the intensive organic because site limitations did not permit an effective establishment of organic coffee with fewer inputs. Once the coffee had been established, was productive and soil conditions had improved, fertilizer levels were dropped from the seventh year onwards (26 fifth harvest year), to below that of the moderate organic in Nicaragua in order to develop nutrient limiting conditions more rapidly. Final adjusted fertilizer rates for the Nicaragua and Costa Rican sites are shown in Table 2. The number of plots and treatments in the final design was limited by available land and labour for maintenance and data collection (Table 3). Treatments were defined to allow comparisons firstly among shade tree characteristics and combinations across moderate input levels, secondly among input strategies under contrasting shade tree characteristics (legume service versus non-legume timber), and thirdly between full sun and two contrasting shade types under conventional management. Three replicas were established at each site forming a randomized block design with shade as main treatments and inputs as sub-treatments within shade. Subplot size varied between 5 and 6 m 2, with measurement plots of m 2 (minimum of 24 shade trees and 1 coffee plants). The full experiment covers 6 ha in Costa Rica and 3 ha in Nicaragua. Coffee, Coffea arabica L. var. Catuura, was planted at 8, plants per ha in Costa Rica by planting two plants per planting hole a common practice there. In Nicaragua Coffea arabica var Pacas was planted at a density of 4, plants per ha. 288 Agroforest Syst (211) 82: Table 2 Levels of nutrients applied in organic and conventional fertilizer application in Costa Rica and Nicaragua since 26 Moderate organic (MO) Intensive organic (IO) Moderate conventional (MC) Intensive conventional (IC) Costa Rica 46 kg N ha kg N ha kg N ha -1 3 kg N ha -1 2kgPha kg P ha -1 1 kg P ha -1 2 kg P ha kg K ha -1 (coffee pulp 5 t ha -1 ) 326 kg K ha -1 (chicken manure 1 t ha 1 1 kg Kmag ha -1 ) 75 kg K ha kg K ha -1 Nicaragua 56 kg N ha kg N ha kg N ha kg N ha -1 3kgPha kg P ha -1 2 kg P ha kg P ha kg K ha -1 (coffee pulp 9 t ha -1 ) 145 kg K ha -1 (coffee pulp 9 t ha -1 chicken manure 7 t ha -1 ) 43 kg K ha kg K ha -1 The source of nutrients applied is indicated for the organic treatments. Note the quality of the coffee pulp and chicken manure are distinct in Costa Rica and Nicaragua: coffee pulp in Nicaragua is fresh and so has higher concentration of potassium but also greater water content, while in Costa Rica it is composted; the chicken manure in Nicaragua is mixed with rice husks, while that in Costa Rica it is pure manure but processed Table 3 Main plot (shade tree combinations) and subplot input treatments Main plot Full sun (FS) Erythrina (EP) Terminalia (TA) Chloroleucon (CE) Terminalia? Chloroleucon (CETA) Terminalia? Erythrina (EPTA) Chloroleucon? Erythrina (CEEP) Costa Rica Subplot IC, MC IC, MC, IO, MO IC, MC, IO, MO MC, IO MC, IO MC, IO IC, MC, IO, MO Main plot treatments Full sun (FS) Simarouba, Tabebuia (SGTR) Tabebuia, Samanea (SSTR) Inga? Simarouba, (ILSG) Inga,? Samanea (ILSS) Nicaragua Subplot treatments IC, MC IC, MC, IO, MO MC, IO MC, IO IC, MC, IO, MO Coffee bushes were selectively stump pruned after each harvest depending on the productive potential of the plant for the following harvest. This method of pruning allows each treatment to develop according to its productive potential, without being affected by the pruning regime. Shade trees were planted at 417 trees per ha in Costa Rica and 667 trees per ha in Nicaragua, a density four times greater than the expected final density. During the time reported here, one thinning was conducted reducing the tree density by 5%, timing of the thinning varied according to species development. In Nicaragua the legume timber tree originally selected and planted was Enterolobium cyclocarpum (Jacq.) Griseb., however, after 2 years tree growth was very poor and variable, thus it was considered necessary to replace it with Samanea saman, which was planted in 22. The traditional management of Erythrina shade trees in Costa Rica consists of two complete prunings (pollarding) each year leaving only the main trunk to a height of about m. However, based on recent studies in Costa Rica of the effect of shade levels on coffee quality (Muschler 21), Erythrina management was varied by treatment. In the intensive conventional treatment, Erythrina is pruned completely (pollarded) twice a year. In all the other treatments with Erythrina, a minimum of three branches were left for partial shade cover after each of the two annual prunings. In all cases, the pruned material is left on site. Temporary shade of Ricinus was planted a year after the coffee in the organic Agroforest Syst (211) 82: treatments to suppress weed growth and to improve coffee plant survival. Timber trees had their lower branches pruned each year to improve their form, pruned material was left on the ground. Only the trunks of the thinned trees of the timber species were removed, branches and leaves were left on site. In Nicaragua temporary shade was established for all treatments with permanent shade. Ricinus comunis was the non-n fixing species, while Cajanus cajan was the N-fixing species planted. Temporary shade was seeded between every coffee plant and then thinned to provide biomass for soil improvement and to achieve overhead shade to suppress weeds and diminish light intensity for the recently planted coffee plants. Thinning and replanting were used to manage overall shade in each plot. Temporary shade was eliminated in the fourth year by which time the permanent shade trees had established. Timber species are pruned to achieve a marketable main trunk, while Inga is managed to create a uniform shade distribution. Inga is prunned once per year, removing branches to form the tree and regulate shade levels to approximately 4% cover. Nevertheless, the primary regulation of the shade levels by the timber trees was through thinning. A first thinning was conducted in 25 reducing tree density to 333 trees per ha apart from those treatments with Samanea, which was planted, and thus also thinned, 2 years later. Both for prunings and thinnings large branches and trunks were removed from the plots as firewood and posts, but small branches and leaves were left on site. Evaluation of the treatments Measurement of production and yield conversions Starting in 23, coffee yields were measured annually, weighing the coffee cherries produced from the measurement plots, leaving borders of at least two coffee rows or three coffee plants around each treatment plot. At the Costa Rica site coffee productivity was only measured in terms of the weight of coffee cherries. In Nicaragua, a sample of approximately 11 kg of coffee cherries was taken from each plot during the peak harvest time to measure conversion rates from coffee cherries to green coffee. These samples were wet milled manually, dried and processed to green coffee, registering the weight conversion between each step in order to calculate a conversion index and subsequently the productivity of each system in terms of green coffee. Measurement of tree size and shade cover Height and diameter of trees within the measurement plot (leaving a border of one tree around the edge of each plot) were measured annually during the first 5 years, and then biannually subsequently. Shade cover was measured from the centre of each plot using a densiometer taking four readings in each cardinal direction (Lemmon 1956). In Costa Rica, measurements were conducted in only 1 year (25) evaluating shade levels before and after pruning of shade trees. In Nicaragua these measurements were taken twice per year, in the dry season and the wet season. Measurement of biomass inputs and nutrient recycling In Costa Rica, biomass removed by pruning was estimated through student theses that differ slightly in their methodology (Montenegro 25; Romero26). In summary, four or five trees were randomly selected in each shade-input treatment combination and the biomass produced from pruning was separated into leaves, small branches and large branches, weighed wet in the field and sub-samples taken to measure water and nutrient content of each component. In 26, six litter traps (1 9 5 cm) were placed in each shade treatment positioned at different distances from the base of the shade trees. Litter was collected from the traps every 7 days during 8 months. In Nicaragua, on each occasion that trees were pruned or thinned, the biomass pruned was measured from four to eight trees per species per shade combination. Biomass pruned was estimated at the plot level by multiplying the average amount of biomass removed by the number of trees intervened. Biomass removed was separated into leaves, branches\2 cm, branches[2 cm and trunks. A similar sampling strategy and measurements were used to estimate tree biomass removed in trees thinned in 25. In the dry season of 24, the litter layer was sampled and weighed from six randomly placed.5 m 2 quadrants per treatment plot, and separated by components tree and coffee leaves and branches, dry and living weeds and decomposed leaf litter by size of material. Dry matter and nitrogen were determined on a sub-sample for each type of material. Measurement of soil fertility The effect of treatments on soil characteristics was studied in 29 Agroforest Syst (211) 82: and 24. Soil samples were taken at two depths ( 1 cm and 1 2 cm), and separate samples were taken within the row and between rows. Six subsamples were taken from within each shade-input treatment plot and mixed as a composite sample for analysis. In 24, resources only permitted the sampling of the intensive organic and moderate conventional treatments. Soil variables measured were ph, acidity, cation exchange capacity, Ca, Mg, K, P, Cu, Zn, Mn, Fe, and organic matter. Soil samples in Costa Rica were analyzed at CATIE using the Olsen extraction for P, and 1 N HCl for Ca, Mg and acidity, and Walkey and Black for organic matter. In Nicaragua soil analysis were done at the Universidad Nacional Agraria using Walkey and Black for organic matter, New Zealand extraction for P, NaCl extraction for CICE and cations. Nitrogen mineralization estimates were conducted using anaerobic incubation following the method presented
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