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Almacenamiento de carbono en sistemas agroforestales en los Llanos Orientales de Colombia
No full textCarbon storage in agroforestry systems in Colombia’s Eastern Plains. Introduction: Coffee, cocoa crops and pastures for livestock are agricultural activities of economic interest in Colombia. When these activities are developed under agroforestry systems (AFS), they promote conservation and increase carbon fixation and, therefore, climate change mitigation. Objective: The study estimated carbon storage in aboveground biomass, necromass and soil organic carbon under SAF with cocoa (SAF cocoa), SAF with coffee (SAF coffee), silvopastoral systems (SPS) and forest in Mesetas, Meta (Colombia). Methods: Forty-four sampling plots were established, where dasometric measurements were taken from individuals with a trunk diameter at breast height (dbh) ≥ 2.5 cm (saplings, trees and large trees), whose values were transformed to carbon with biomass models and a default carbon fraction. In the three agricultural systems, the number of cocoa and coffee trees and associated plants was counted, and the type of use (timber, food, combustion) was identified. Results: Carbon storage showed significant differences (P < 0.0001) among land uses. The highest accumulation was found in forest, with 216.6 t C ha-1, exceeding in 59, 72 and 73 % to SAF cocoa, SSP and SAF coffee, respectively. The botanical families Fabaceae, Lauraceae and Primulaceae presented the greatest carbon storage. In SAF cocoa, the greatest accumulation of carbon was found in species for human food; in SAF coffee and SSP, the greatest storage was presented by timber species
Selecting a core set of nuclear SNP markers for molecular characterization of Arabica coffee (Coffea arabica L.) genetic resources
No full textCoffee is one of the most economically important agricultural commodities in the world. Labeling accuracy and conservation efficiency are essential for coffee germplasm management and for the exchange and utilization in breeding new varieties. However, due to its homogenous genetic background, accurate identification of Coffea arabica germplasm has not been fully achieved. Specifically, data comparison across different laboratories and genotyping platforms has not been available. Here, we report the screening of 672 candidate SNPs using Nano-Fluidic Array genotyping. Based on call rate, Minor Allele Frequency and Linkage Disequilibrium, a set of 96 SNPs were selected for genotyping C. arabica. This validated panel is suitable for use in coffee germplasm conservation and crop improvement, including varietal identification, seeds and nursery accreditation, and coffee bean authentication
The positive association between natural vegetation, native coccinellids and functional diversity of aphidophagous coccinellid communities in alfalfa
No full text1. A greater taxonomic and functional diversity of natural enemies in agroecosystems is frequently positively associated with more effective pest control, due to the complementarity of species or traits. But this diversity has declined with landscape homogenisation and loss of natural covers, particularly losing native species, which play an important role in pest suppression within crops.
2. We evaluated the effect of landscape on coccinellid communities and aphids, and the relative contribution of coccinellids and aphids in shaping taxonomic and functional diversity of coccinellid communities in alfalfa fields.
3. We characterised the landscape at 1 kmradius surrounding 17 alfalfa fields, and the taxonomic and functional diversity of coccinellid communities collected throughout the season in alfalfa. Functional diversity indices considered four traits: body size, habitat specialisation, ubiquity and temporal variability.
4. We found a positive association among native coccinellids in alfalfa and the amount of natural cover in the landscape, while aphids positively associated with agricultural cover. Also, we found a positive association among functional and taxonomic diversity indices with native coccinellids, and a negative association with exotics, demonstrating the contribution of native coccinellids in adding taxonomic and functional diversity to the aphidophagous communities in alfalfa fields. Aphids also associated positively with some functional and taxonomic diversity indices.
5. Our results highlight the need to promote appropriate management practices in agricultural landscapes in order to conserve native coccinellid species in alfalfa, maintain a diversified species pool and their potential for aphid pest suppression
Cacao agroforestry systems improve soil fertility: Comparison of soil properties between forest, cacao agroforestry systems, and pasture in the Colombian Amazon
No full textThe objective of our work was to evaluate soil quality in different cacao agroforestry systems (AFS) in the Colombian Amazon. We compared soil quality of AFS at the study site with soil quality of two control systems: a pasture and a secondary forest. The study was conducted at the Macagual Amazon Research Center in western Colombian Amazon. We set up eight 600 m2 plots in each study system. We collected soil samples in each plot, and assessed macrofauna diversity, aggregate morphology, and physical and chemical soil properties. We integrated these variables in a General Indicator of Soil Quality (GISQ). We found GISQ values of 0.85 for forest, 0.5, 0.65 and 0.59 for AFS and 0.21 for pasture, and the values differed significantly between land uses. The establishment of cacao AFS on degraded pasture was found to significantly improve soil fertility, i.e., by 42%. The intensification level between land uses (Pasture > AFS > Forest) negatively affected macrofauna populations due to soil compaction (physical properties). Forest had the highest physical and biological quality. Our results show that AFS not only have the capacity to maintain key soil ecological functions, but also to restore soil quality of degraded pastureland. Cacao-based AFS could therefore be a key restoration strategy for degraded pastureland. These results are very important in the context of the Colombian Amazon, where cacao is currently known as the “crop of peace”
Dimensions of social and political capital in interventions to improve household wellbeing: Implications for coffee-growing areas in southern Colombia
No full textThis paper studies the influence of community capitals on well-being through a Community Capital Index (CCI) within coffee-growing families in southern Colombia. Our results show different farm typologies, with different levels of capital endowment translated into wellbeing that, in our case, were represented in the CCI. Specifically, social and political capitals positively affect coffee-growing families’ decisions in terms of life strategies. The results of this study increase our understanding of welfare enhancement and its relationship with capital endowment according to the type of coffee producer, having implications for the planning of more effective programs towards the improvement of quality of life
Economic valuation of the ecosystem services provided by the mangroves of the Gulf of Nicoya using a hybrid methodology.
No full textDue to the public good nature of many of mangrove’s ecosystem services, markets for them do not exist and there is limited potential to manage them with conventional markets. Moreover, because of the difficulties in estimating the value of these non-marketed services, mangroves are often undervalued in benefit cost analysis of conservation versus commercial land uses causing their degradation and loss. With the goal of supporting the current efforts of the government of Costa Rica to develop a new PES scheme that include these ecosystems, as well as other policy initiatives on wetlands conservation and restoration, we applied a hybrid approach to estimate the value of ecosystem services from mangrove forests in the Gulf of Nicoya. Our method consists of traditional benefit transfer and expert modified benefit transfer for 11 ecosystem services, and the application of more specific methods to estimate three of those ecosystem services (i.e. climate regulation, fisheries and coastal protection). Using traditional benefit transfer, we estimated the total economic value of ecosystem services of mangroves in the Gulf of Nicoya in 88 million/year), and the total mean value of the ecosystem services provided by all the mangroves in Costa Rica as 160 million/year). By applying the expert modified benefit transfer we estimated that the mean total value of the mangrove forests of the Gulf of Nicoya is 75 million per year..
Species interactions across trophic levels mediate rainfall effects on dryland vegetation dynamics
No full textArid ecosystems are strongly limited by water availability, and precipitation plays a 2 major role in the dynamics of all species in arid regions, as well as the ecosystem processes that 3 occur there. However, understanding how biotic interactions mediate long-term responses of 4 dryland ecosystems to rainfall remains very fragmented. We report on a unique large-scale field 5 experiment spanning 25 years and three trophic levels (plants, small mammal herbivores, 6 predators) in a dryland ecosystem in the northern Chilean Mediterranean Region where we 7 assessed how biotic interactions influence the long-term plant community responses to 8 precipitation. As the most persistent ecological changes in dryland systems may result from 9 changes in the structure, cover, and composition of the perennial vegetation, we emphasized the 10 interplay between bottom-up and top-down controls of perennial plants in our analyses. Rainfall 11 was the primary factor affecting the dynamics of, and interactions among, plants and small 12 mammals. Ephemeral plant cover dynamics closely tracked short-term annual rainfall, but seemed 13 unaffected by top-down controls (herbivory). In contrast, the response of the perennial plant cover 14 to precipitation was mediated by: (i) a complex interplay between subtle top-down (herbivory) 15 controls that become more apparent in the long-term, (ii) competition with ephemeral plants 16 during wet years, and (iii) an indirect effect of predators on subdominant shrubs and perennial 17 herbs...
Discovering weather periods and crop properties favorable for coffee rust incidence from feature selection approaches
No full textCoffee Leaf Rust (CLR) is a disease that leads to considerable losses in the worldwide coffee industry; as those that have been reported recently in Colombia and Central America. The early detection of favorable conditions for epidemics could be used to improve decision making for the coffee grower and thus reduce the losses due to the disease. Researchers tried to predict the occurrence of the disease earlier through statistical and machine learning models from crop properties, disease indicators and weather conditions. These studies considered the impact of weather variables in a common period for all. Assuming that the dynamics of weather that most impact the development of the disease occur in the same time periods is simplistic. We propose an approach to discover the time period (window) for each weather variables and crop related features that most explain a future observed CLR incidence, in order to obtain a prediction model through machine learning. The selection of the variables more related with coffee rust incidence and rejection of the features with no significant contribution of information in machine learning tasks were approached from Feature Selection methods (Filter, Wrapper, Embedded). In this way, a CLR incidence prediction model based on the features with the greatest impact on the development of the disease was obtained. Moreover, the use of SHapley Additive exPlanations allowed us to identify the impact of features in the model prediction..
