Estudio explorativo de técnicas de bajo costo para la regeneración de los horizontes a y o, en los suelos de interés en zonas potenciales de conservación y recarga hídrica de la micro-cuenca de las quebradas Caracol y Trapiche, San Ramón de Alajuela, Costa Rica

CATIE - Centro Agronómico Tropical de Investigación y Enseñanz

Economic constraints as drivers of coffee rust epidemics in Nicaragua

Coffee rust (Hemileia vastatrix) epidemics of an intensity never seen before have hit Central America since 2012. This study set out to identify management and socio-economic factors that facilitate coffee rust development in Nicaragua and to learn how farmers perceive these epidemics. To that end, we conducted a series of interviews with farmers and carried out field observations a year after the peak of the 2012-13 epidemic. Twenty-nine pairs of plots (a pair was one heavily hit plot and another slightly hit plot in the same location) in the municipalities of Jinotega, Tuma-La Dalia and San Ram?on were characterized for their management and coffee rust impact. This information was completed through interviews with the farmers. In addition, farmers provided their perception of the reasons for differences of coffee rust intensities between plots and information about their socio-economic situation. From multivariate analyses, we deduced that young coffee trees, timely applications of fungicides based on disease monitoring, shade pruning, and soil and foliar fertilizers seemed to be key practices in managing coffee rust. These practices were well known by the farmers, but socio-economic difficulties severely held back their application, as revealed by a mental model approach. Low coffee economic resources were particularly mentioned by farmers as a constraint to applying the practices needed to manage coffee rust. The highest coffee rust intensities and impacts were found in plots where the farmers, in general, had no education, no training, a low number of direct technical advices, and low incomes. To our knowledge, this is the first time that poor economic conditions have been related to the development of intense plant disease outbreaks. These relationships indicated that technical solutions to manage coffee rust are not sufficient and that economic solutions, where the market has a crucial role to play, need to be implemented

Bosques tropicales estacionalmente secos son importantes para ganaderos en el noroeste costarricense

In the dry regions of Central America, forests in cattle ranches are used as a refuge for cattle during the dry season, and there is no much information about this practice. To determine the frequency of this practice and how it fits in farm management. We conducted semi-structured interviews with cattle ranchers in 43 farms in Liberia County, Guanacaste, Costa Rica. Cattle farmers suffered from the loss of profitability due to droughts, fire, and cattle theft. Cattle browsing in the forest was used by 70 % of farms, mostly between March and May. No type of farm or feeding strategy was associated with forest browsing. The high variability in farm management did not provide a distinct classification of feeding strategies. We found a difference in farm structure and feed types between ranches in the plains and mountain slopes. The decision to use forests for browsing seemed to rely on a trade-off between animal welfare and ease of management. Traditional knowledge about cattle behavior in forests was variable and often limited to forest edges and pastures. This research shows that forests should be taken into consideration when analyzing cattle ranching in dry regions of Central America. We recommend a further study on feeding strategies and the impact of cattle on forest integrity to determine if agricultural policymakers should foster these low-costs alternatives

Effect of Fitohormones and Fertilizers on the Rooting and Growth of Mini-cuttings of Coffee (Coffea arabica) F hybrids

[Introducci?n]: En el Centro Agron?mico Tropical de Investigaci?n y Ense?anza (CATIE) se est? buscando optimizar la t?cnica hort?cola de enraizamiento de mini-estaquillas de caf? para la multiplicaci?n comercial de h?bridos a escala masiva y bajo costo. [Objetivo]: El objetivo de este trabajo fue determinar el efecto de distintos fertilizantes y estimulantes hormonales sobre el ?xito del enraizamiento y posterior crecimiento de las plantas resultantes. [Metodolog?a]: Se utilizaron mini-estaquillas de tres h?bridos de caf?, tratadas con distintas combinaciones de un bioestimulante, un enraizante, una f?rmula a base de multiminerales, vitaminas y fitohormonas, y tres fertilizantes (NP, ZnP, soluci?n hidrop?nica), las cuales fueron puestas a enraizar en t?neles pl?sticos con irrigaci?n. Las plantas enraizadas fueron trasplantadas a bolsas para un periodo de crecimiento en vivero de 3 meses. [Resultados]: La fase de enraizamiento concluy? a las 12 semanas, con un promedio general superior al 89 %, sin diferencias entre tratamientos ni entre h?bridos. Se encontraron diferencias significativas entre tratamientos para longitud de ra?ces, con superioridad de la combinaci?n del enraizante con el fertilizante ZnP. En la fase de vivero hubo diferencias significativas entre tratamientos para altura de plantas, peso fresco de parte a?rea, y peso fresco y seco de ra?ces, logrando destacar, en todos los casos, las combinaciones del enraizante con el complejo de multiminerales o con el fertilizante ZnP. El h?brido L12A28 sobresali? en casi todas las variables evaluadas. [Conclusiones]: El estudio mostr? la importancia del uso de complementos aux?nicos y nutricionales durante la fase de enraizamiento para optimizar el desempe?o de las plantas en vivero. Asimismo, se confirm? la factibilidad de la t?cnica, enraizamiento de estaquillas, como un m?todo simple y eficiente para la multiplicaci?n de los h?bridos

Measured ammonia emissions from tropical and subtropical pastures: A comparison with 2006 IPCC, 2019 Refinement to the 2006 IPCC, and EMEP/EEA (European Monitoring and Evaluation Programme and European Environmental Agency) inventory estimates

Agriculture is the largest source of ammonia (NH3) emissions. As NH3 is an indirect greenhouse gas, NH3 measurements are crucial to improving greenhouse gas emission inventory estimates. Moreover, NH3 emissions have wider implications for environmental and human health. Only a few studies have measured NH3 emissions from pastures in the tropics and subtropics and none has compared emissions to inventory estimates. The objectives of this study were to (1) measure NH3 emissions from dairy pastures in tropical and subtropical regions; (2) calculate NH3 emissions factors (EF) for each campaign; and (3) compare measured EF with those based on the 2006 Intergovernmental Panel on Climate Change (IPCC) Tier 1, 2019 Refinement to the 2006 IPCC Tier 1, and the European Monitoring and Evaluation Programme/European Environmental Agency (EMPE/EEA) Tier 2 inventory estimates. Pasture NH3 emissions were measured on 3 dairy farms in Costa Rica. On each dairy, NH3 emissions were measured twice during the wet season and once during the dry season using a micrometeorological integrated horizontal-flux mass-balance method. Emissions were measured from excreta (dung and urine) deposited by grazing cattle and the subsequent application of organic (slurry) or synthetic fertilizer (ammonium nitrate or urea). Measured EF for all campaigns [from grazing cattle excreta and any subsequent slurry or fertilizer application; 4.9 ? 0.9% of applied nitrogen (mean ? SE)] were similar to those of the EMEP/EEA Tier 2 approach (6.1 ? 0.9%; mean ? SE) and 4 times lower than 2006 IPCC and 2019 Refinement to 2006 IPCC Tier 1 default estimates (17.7 ? 1.4 and 18.2 ? 0.9%, respectively; mean ? SE). Measured EF for excreta deposited on pasture and excreta both deposited on pasture and slurry application [3.9 ? 2.1 and 4.2 ? 2.1% (mean ? 95% CI), respectively] were 5 times lower than default EF assumed by 2006 IPCC and 2019 Refinement to 2006 IPCC methodology (both 20 and 21%, respectively), whereas EMEP/EAA estimates were similar [6.0 and 4.6 ? 0.3% (mean ? 95% CI), respectively]. This suggests an overestimation of EF from excreta deposited on pasture and slurry applications in tropical and subtropical regions by IPCC methodologies. Furthermore, rainfall, which is not included as a parameter in the current EMEP/EEA Tier 2 methodology, appeared to reduce NH3 emissions, suggesting that accounting for this in the inventory methodologies could improve inventory estimates

Unraveling the Complexity of Coffee Leaf Rust Behavior and Development in Different Coffea arabica Agroecosystems

Crop health management systems can be designed according to practices that help to reduce crop losses by restricting pathogen development and promoting host plant growth. A good understanding of pathogen and host dynamics, which are interdependent, is therefore needed. In this article, we used a holistic approach to explain the behavior of coffee leaf rust (CLR), a major coffee disease. We monitored coffee plant and CLR dynamics simultaneously in plots under different disease management and agroforestry systems. Diseased leaves were also collected to characterize inoculum stock and rust life stages (latent rust area, area with uredospores, necrosis due to rust) through picture analysis. We used structural equation modeling to obtain an overview of CLR pathosystem functioning on a plant scale. This overview integrates processes such as disease dilution by host leaf renewal, direct and indirect effects of fruit load on CLR development, antagonistic effects of shading depending on rust life stages, the tonic effect of copper-based fungicides on leaf retention, and effects on rust life stages depending on fungicide types

Coffee agroforestry systems capable of reducing disease-induced yield and economic losses while providing multiple ecosystem services

Crop losses caused by pests and diseases decrease the incomes and threaten the livelihoods of thousands of families worldwide.During two years, in a research network of 61 coffee plots under a wide variety of shade and management conditions in Turrialba, Costa Rica, we quantified primary and secondary coffee losses (yield and economic losses) and indicators of three other ecosystem services: provisioning of agroforestry products (bananas, plantains, other fruits, and timber), maintenance of soil fertility and carbon sequestration. We then performed an analysis of the relationships between losses and ecosystem service indicators. Our results suggest that the regulation of diseases and associated losses in agroforestry systems should be based on, and take advantage of, the positive effects of plant biodiversity, adequate shade cover, good soil fertility, and minimal use of fungicides

Evaluaci?n del estado de la vegetaci?n ribere?a en r?os con influencia de proyectos hidroel?ctricos, provincia de Chiriqu?, Panam?

CATIE - Centro Agron?mico Tropical de Investigaci?n y Ense?anz