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9 pages, 1 tables, 1 figure.-- This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY), The anthropogenic introduction of significant amounts of reactive nitrogen in the coastal zone particularly since the discovery and application of the Haber-Bosch process has profound consequences over organic carbon storage and transformations at both regional and global scales. Here, we review our current knowledge on cause-effect chains for nitrogen, especially dissolved inorganic nitrogen, on organic carbon cycling in coastal tropical systems. We focus on the feedback mechanisms for turnover of different organic carbon species to nitrogen excess and links to current environmental and climate changes. We pay special attention to organic carbon dynamics in tropical coasts due to their high primary productivity, rapid sedimentation, and significant needs of nitrogen for agriculture and industry usages. Together with land-use changes and economy development, we highlight the vulnerability of carbon storage in tropical coasts triggered by nitrogen overloading and outline possible industrial strategies with low carbon cycling disturbance to benefit the development of tropical countries, This work is supported by the National Natural Science Foundation of China (Nos. 42090043 and 41876074)

The alarming pace of tropical biodiversity loss requires development of innovative approaches for in situ biodiversity conservation. Incentive-based approaches have emerged as one possible option. We interviewed 68 private nature reserve owners to learn more about one of Costa Rica's incentive programs. The interview group included all reserve owners participating in the government's Private Wildlife Refuge Program (n = 22) and a control group of nonparticipating owners (n = 46). Quantitative and qualitative data led to seven main conclusions on the use of incentive programs: (1) a developing country can expand and enhance its formal park system through conservation incentives; (2) insufficient promotion, and resulting information gaps, can prevent an incentive program from realizing its full potential; (3) landowners enter a program not only in response to the intended incentive package, but also for several powerful and hidden incentives such as publicity and marketing purposes; (4) underutilization of official incentives by participants, in part due to sporadic delivery of incentives by the government, can undermine program effectiveness; (5) biodiversity protection goals can be accomplished by means of a wide range of incentives; (6) programs that require only a short-term commitment by landowners can still lead to long-term biodiversity protection; and ( 7) a program can produce unanticipated negative consequences at the national level, including putting conservation at odds with social justice. These and other lessons on the use of incentives should be of interest wherever biodiversity is threatened, wherever new conservation partners are being sought, and wherever incentive-based approaches are being considered.El alarmante ritmo al que se pierde biodiversidad tropical requiere del desarrollo de estrategias innovadoras para la conservación in situ. Las estrategias basadas en incentivos han emergido como una posible opción. En este estudio entrevistamos a 68 dueños de reservas naturales privadas para conocer más acerca de los programas de incentivos de Costa Rica. El grupo entrevistado incluyó a todos los dueños de reservas que participan en el Programa de Gobierno de Refugios Privados de Vida Silvestre (n=22) y un grupo control de dueños que no participan en el programa (n=46). Los datos cuantitativos y cualitativos conducen a siete conclusiones principales sobre el uso de programas de incentivos: 1) un país en desarrollo puede expandir y mejorar su sistema formal de parques mediante incentivos para la conservación; 2) la promoción insuficiente y los resultantes huecos en la información pueden impedir la realización del potencial total de un programa de incentivos; 3) los dueños de tierras entran a un programa no solo en respuesta al paquete de incentivos proyectado, sino también por diversos incentivos poderosos y ocultos como lo son la publicidad y objetivos de mercadeo; 4) la baja utilización de incentivos oficiales por los participantes, debida en parte al envío esporádico de incentivos por el gobierno, puede socavar la efectividad del programa; 5) la metas de protección de biodiversidad pueden ser alcanzadas usando un amplio rango de incentivos; 6) los programas que requieren únicamente de compromisos a corto plazo por parte de los propietarios de tierras pueden también conducir a una protección de la biodiversidad a largo plazo; y 7) a nivel nacional, un programa puede producir consecuencias negativas no anticipadas, incluyendo el poner a la conservación en disparidad con la justicia social. Estas y otras lecciones sobre el uso de incentivos deben ser de interés donde la biodiversidad está amenazada, donde se han visualizado nuevos partícipes para la conservación, y donde los métodos basados en incentivos están siendo considerados.

Objective: the anthelmintic efficacy of albendazole and levamisole in Strongyloides sp. populations was assessed in buffalo calves (Bubalus bubalis) with natural infections in the Mexican tropic. Materials and methods: 45 buffalo calves were included in the study and distributed into three experimental groups (15 specimens each), according to the excretion of eggs of Strongyloides sp. per gram of faeces (EPG), namely: (a) Control group: without de-worming; (b) BZ group (benzimidazoles), which received oral albendazole (10 mg/kg); and (c) IMIDA group (imidazothiazoles) that received levamisole (8 mg/kg) subcutaneously. Faeces were obtained directly from the rectum on days zero (pre-treatment) and 10 (post-treatment) to determine the EPG of each animal. The samples were processed using the McMaster technique. The EPG results were analysed using the RESO software to determine the percentages of egg reduction and their 95% confidence intervals (95% CI). Results: the BZ group exhibited 94% reduction in EPG (95% CI = 87-97), and the IMIDA group exhibited 95% reduction in EPG (95% CI = 84-99). Conclusion: this is the first report in Mexico on the occurrence of Strongyloides sp. populations resistant to benzimidazoles and imidazothiazoles in naturally infected buffaloes from the Mexican tropic., Objetivo. Se evaluó la eficacia antihelmítica de albendazol y levamisol sobre poblaciones de Strongyloides sp. en bucerros (Bubalus bubalis) con infecciones naturales en el trópico Mexicano. Materiales y Métodos. Se incluyeron 45 bucerros, que fueron distribuidos en tres grupos experimentales de acuerdo a la excreción de huevos por gramo de heces (HPG) de Strongyloides sp. (n=15): a) Grupo control: sin desparasitación, b) Grupo BZ (benzimidazoles) que recibó albendazol a razón de 10 mg/kg vía oral, y c) Grupo IMIDA (imidaziotazoles) dosificación de levamisol a razón de 8 mg/kg vía subcutánea. Para determinar los HPG de cada animal, se obtuvieron heces directamente del recto los días 0 (Pre-T) y 10 (PT). Las muestras fueron procesadas mediante la técnica de McMaster y los resultados de HPG se analizaron mediante el programa RESO para conocer el porcentaje de reducción de huevos y sus intervalos de confianza al 95% (IC95%). Resultados. El grupo BZ registró un 94% de reducción de HPG (IC95%= 87–97) y el grupo IMIDA registró 95% de reducción en el HPG (IC95%= 84-99). Conclusión. Se reporta por primera vez en México la presencia de poblaciones de Strongyloides sp. resistentes a benzimidazoles e imidazotiazoles en bucerros del trópico mexicano infectados naturalmente.

Made available in DSpace on 2022-04-29T08:32:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-12-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) River streams are sensitive to environmental changes in drainage basins in response to external and internal forcing. These changes lead to drainage channel adjustments and may alter erosion-sedimentation cycles along valleys, as well as short and long term geomorphological evolution. Concerning the low latitude semi-arid region in South America, fluvial responses to environmental changes during the Upper Holocene have still not been adequately assessed, contrasting with evaluations in river drylands located in middle latitudes. To collaborate with assessments on Upper Holocene climatic fluctuations, alluvial deposits at the Itapicuru River, located in the Brazilian semi-arid, were analyzed to understand this river's dynamics in the last 5 ka and its relationship with both intrinsic and extrinsic factors. The following analyses were performed: [1] spatial terrace distribution throughout the river's longitudinal profile, [2] stratigraphic section assessments, [3] OSL dating, to estimate surface time elaboration, and [4] age correlations with regional paleoclimatic models. In the last 2.2 ka, downcutting and lateral migration occurred at the same time due to fluvial discharge changes over centuries and decades. Semi-arid conditions, such as those currently observed, prevailed throughout the drainage basin, with wet intervals identified upstream. Humidity variations were responsible for middle valley incision and deposition, forming terrace, bars, and natural levees. These findings indicate that, at least in our case study, intrinsic factors had big importance to control the fluvial dynamics since the establishment of the semi-arid low latitude climatic conditions. Department of Geography Campus Garanhuns University of Pernambuco (UPE) Department of Geography Institute of Geoscience State University of Campinas (UNICAMP) Department of Geography and Environmental Planning Campus Rio Claro São Paulo State University “Júlio de Mesquita Filho” (UNESP) Department of Geography Institute of Geoscience University of Campinas (UNICAMP) Department of Humanities Campus Jacobina University of Bahia State (UNEB) Department of Geography and Environmental Planning Campus Rio Claro São Paulo State University “Júlio de Mesquita Filho” (UNESP) CAPES: 001 FAPESP: 2012/00145–6 FAPESP: 408333/2013–8

Introduction.The use of forage oat silage (Avena sativaL.) in dairy cattle in times of feed deficit, allows mitigating biomass losses due to drought in the Colombian high tropics.Objectives.1) To determine the dry matter yield (DMY) of five forage oat genotypes and the phenotypic stability and the bromatological quality of their silage, and 2) to evaluate the inclusion of the AV25-T genotype silage in diets for dairy cattle.Materials and methods.In the Colombian high tropics two experiments were performed: 1) agronomic evaluation test (October 2017 and February 2018) in a randomized complete block design with five genotypes, eight locations, and four replicates; dry matter yield (DMY) and protein, neutral detergent fiber (NDF) and total digestible nutrients (TDN) contents in silage were determined, and 2) animal response study (January 2018) with the inclusion of the AV25-T genotype in diets, in a simple crossover design with two factors: animal (5) and diets (3); the diets were: D1: only meadow; D2: 35 % AV25-T silage + grazing, and D3: 65 % AV25-T silage + grazing. Milk yield, protein, fat, total solids, were determined in the milk, and weight change was determined in the animals.Results.AV25-T presented adaptation with the highest DMY. The inclusion of AV25-T silage in the animal diet showed a significant change in animal weight (0.1 and 0.25 kg with D2 and D3), milk yield (27.2 - 29.7 L/cow/day with D3 and D2), and the fat content (3.2 - 3.9 % with D3 and D2), without detriment in protein and total solids.Conclusion.The use of AV25-T forage oats in silage allowed increases in animal weight, milk yield, and fat content in Holstein dairy cows without affecting protein and total solids in milk. Introducción.Utilizar ensilaje de avena forrajera (Avena sativaL.) en la ganadería de leche en épocas deficitarias de alimento, permite mitigar pérdidas de biomasa por sequía en el trópico alto colombiano.Objetivos.1) Determinar el rendimiento en materia seca (RMS) de cinco genotipos de avena forrajera y la estabilidad fenotípica y la calidad bromatológica de su ensilaje, y 2) evaluar la inclusión de ensilaje del genotipo AV25-T en dietas para ganado lechero.Materiales y métodos.Se realizaron en el trópico alto colombiano dos experimentos: 1) prueba de evaluación agronómica (octubre de 2016 a febrero de 2017) en un diseño de bloques completos al azar con cinco genotipos, ocho localidades y cuatro repeticiones; se determinó el rendimiento en materia seca (RMS) y en ensilaje los contenidos de proteína, fibra en detergente neutro (FDN) y nutrientes totales digestibles (NTD) y 2) estudio de respuesta animal (enero 2018) con la inclusión del genotipo AV25-T en dietas, en un diseño Crossover simple con dos factores: animal (5) y dietas (3); las dietas fueron: D1: solo pradera; D2: 35 % de ensilaje AV25-T + pastoreo y D3: 65 % de ensilaje AV25-T + pastoreo. Se determinó en la leche la producción, la proteína, la grasa y los sólidos totales, y en el animal el cambio de peso.Resultados.AV25-T presentó adaptación con el mayor RMS. La inclusión de ensilaje de AV25-T en la dieta animal, mostró un cambio significativo en el peso del animal (0,1 y 0,25 kg con D2 y D3), el rendimiento de leche (27,2 - 29,7 L/vaca/día con D3 y D2) y el contenido de grasa (3,2 - 3,9 % con D3 y D2), sin detrimento en proteína y sólidos totales.Conclusión.El uso del ensilaje de avena forrajera AV25-T permitió en vacas lecheras Holstein incrementos en el peso animal, el rendimiento de leche y el contenido grasa sin afectar la proteína y los sólidos totales.

RESUMEN: Los acuíferos freáticos constituyen una fuente estratégica de agua para diversas actividades y consumo humano alrededor del mundo. Además, son sistemas esenciales en la regulación del ciclo hidrológico y de todos los procesos ecosistémicos que de él derivan, especialmente en regiones húmedas tropicales. Estos acuíferos pueden ser vulnerables a la contaminación, a la sobrexplotación e intrusión de agua salada. Esta tesis de doctorado busca comprender el funcionamiento y dinámica de un acuífero freático heterogéneo, basado en su comportamiento hidrodinámico, procesos hidrogeoquímicos y tiempos de tránsito y residencia del agua subterránea. El caso de estudio corresponde al acuífero freático del Golfo de Urabá, Colombia. Los resultados de la tesis muestran que el acuífero freático presenta una importante recarga y una relación directa entre los niveles piezométricos y la precipitación al inicio de la dirección del flujo de agua subterránea. A medida que el flujo de agua subterránea avanza, el patrón de respuesta a nivel piezométrico, sugiere flujos adicionales a la infiltración de la precipitación, como el drenaje de aguas subterráneas, oscilación de mareas y posibles entradas de flujo superficial. La composición hidrogeoquímica del agua subterránea se rige principalmente por el contacto del agua y el suelo con CO2 (g), que induce la meteorización de silicatos, lo que resulta en facies HCO3--Ca2+-Mg2+. La composición isotópica del agua subterránea con una media de δ18O de -6,16 ‰ es consistente con la composición isotópica de precipitación, lo que confirma la recarga directa de la precipitación. Diferentes trazadores como 3H, 14C y CFC’s validaron la infiltración de agua de lluvia en el acuífero y una mezcla de aguas más jóvenes (0 años) con aguas relativamente más antiguas (más de 40 años), conforme con la tasa de renovabilidad estimada según hidrodinámica. La información integrada de los resultados parciales permitió elaborar un modelo hidrogeológico conceptual que representa el funcionamiento del acuífero. ABSTRACT: Phreatic aquifers are a strategic source of water for various activities and human consumption around the world. In addition, they are essential systems in the regulation of the hydrological cycle and all the resulting ecosystem processes, especially in tropical humid regions. These aquifers may be vulnerable to pollution, overexploitation and salt water intrusion. This thesis seeks to understand the functioning and dynamics of a heterogeneous phreatic aquifer, based on its hydrodynamic behavior, hydrogeochemical processes and transit and residence times of groundwater. The case study corresponds to the groundwater aquifer in the Gulf of Urabá, Colombia. The results of the thesis show that the groundwater aquifer presents an important recharge and a direct relationship between the piezometric levels and the precipitation at the beginning of the direction of the groundwater flow. As groundwater flow advances, the piezometric response pattern suggests additional flows to precipitation infiltration, such as groundwater drainage, tidal oscillation, and possible surface flow inputs. The hydrogeochemical composition of groundwater is mainly governed by the contact of water and soil with CO2 (g), which induces silicate weathering, resulting in HCO3--Ca2+-Mg2+ facies. The isotopic composition of groundwater with an average δ18O of -6.16 ‰ is consistent with the isotopic composition of precipitation, which confirms the direct recharge of precipitation. Different tracers such as 3H, 14C and CFC’s validated the infiltration of rainwater into the aquifer and a mixture of younger waters (0 years) with relatively older waters (more than 40 years), in accordance with the estimated renewal rate according to hydrodynamics. The integrated information from the partial results allowed the development of a conceptual hydrogeological model representing the functioning of the aquifer.

Se seleccionó la licencia Creative Commons para este envío. El documento trae lo siguiente: © 2020 Agronomía Mesoamericana es desarrollada en la Universidad de Costa Rica bajo una licencia Creative Commons Atribución-NoComercial-SinDerivar 4.0 Internacional. Para más información escriba a pccmca@ucr.ac.cr o pccmca@gmail.com Introduction. Livestock information systems, besides being indispensable for the daily management of the herd, can serve as a basis for research at the population level. Objective. The objective of the study was to analyze the role of the VAMPP® system as a source of information for cattle population research over 32 years of evolution in Costa Rica. Materials and methods. A statistical analysis of the system database (VAMPP®) covering the period between 1987 and 2018 was carried out. Trends in the dissemination and adoption of the system were evaluated according to period, area, production system, and herd size. The use of information for the exploration of trends by breed and area was exemplified. The contribution of the system at the academy level and production of scientific literature was quantified. Results. 2285 herds (88.8 % specialized dairy and 11.2 % dual purpose) were counted with an average of 9.4±7.9 years of follow-up in the VAMPP® system. The areas with greater diffusion were the very humid premontane forest (29 %) and very humid tropical forest (25 %). The average size of the herd was 124±255 adult cows. The system contains records on 404 316 cows, mostly of Holstein (36.3 %), Jersey (24.6 %), and Holstein×Jersey (20.9 %) breeds. The database includes information on 1,249,557 calvings, 16,223,260 records of daily milk production, and 443,108 health events, predominantly related to mastitis (35.6 %) and laminitis (14.1 %). The system has been used for the elaboration of at least 74 investigations leading to academic degrees and the production of 71 scientific articles, mainly related to health and genetic issues. Conclusion. The information obtained from the VAMPP® system has allowed a detailed characterization of the productive performance of local dairy cattle. Introducción. Los sistemas de información ganadera, además de ser indispensables para el manejo diario del hato, pueden servir de base para la investigación a nivel poblacional. Objetivo. El objetivo del estudio fue analizar el rol del Sistema VAMPP® como fuente de información para la investigación en poblaciones bovinas a lo largo de 32 años de evolución en Costa Rica. Materiales y métodos. Se realizó un análisis estadístico de la base de datos del sistema (VAMPP®) en Costa Rica, que abarcó el periodo entre 1987 y 2018. Se evaluaron tendencias en diseminación y adopción del sistema según periodo, zona, sistema de producción, y tamaño del hato. Se ejemplificó el uso de la información para la exploración de tendencias por raza y zona. Se cuantificó el aporte del sistema a nivel de academia y producción de literatura científica. Resultados. Se contabilizaron 2285 hatos (88,8% de lechería especializada y 11,2 % de doble propósito) con un promedio de 9,4±7,9 años de seguimiento en el sistema VAMPP®. Las zonas con mayor difusión fueron el bosque muy húmedo premontano (29 %) y bosque tropical muy húmedo (25 %). El tamaño promedio de los hatos fue de 124±255 vacas adultas. El sistema contiene registros sobre 404316 vacas, mayoritariamente de razas Holstein (36,3 %), Jersey (24,6 %) y Holstein×Jersey (20,9 %). La base de datos incluye información sobre 1 249 557 eventos de parto, 16 223 260 registros de producción diaria de leche y 443 108 eventos de salud, entre los cuales predominan eventos de mastitis (35,6 %) y laminitis (14,1 %). El sistema ha sido utilizado para la elaboración de al menos 74 investigaciones conducentes a grados académicos y la producción de 71 artículos científicos, principalmente relacionados con temas de salud y genética. Conclusión. La información obtenida a partir del sistema VAMPP ha permitido realizar una detallada caracterización del rendimiento productivo del ganado lechero local. Universidad de Costa Rica, Costa Rica Universidad Nacional, Costa Rica Universidad Nacional Autónoma de México, México Escuela de Medicina Veterinaria

Objetivo. Se evaluó la eficacia antihelmítica de albendazol y levamisol sobre poblaciones de Strongyloides sp. en bucerros (Bubalus bubalis) con infecciones naturales en el trópico Mexicano. Materiales y Métodos. Se incluyeron 45 bucerros, que fueron distribuidos en tres grupos experimentales de acuerdo a la excreción de huevos por gramo de heces (HPG) de Strongyloides sp. (n=15): a) Grupo control: sin desparasitación, b) Grupo BZ (benzimidazoles) que recibó albendazol a razón de 10 mg/kg vía oral, y c) Grupo IMIDA (imidaziotazoles) dosificación de levamisol a razón de 8 mg/kg vía subcutánea. Para determinar los HPG de cada animal, se obtuvieron heces directamente del recto los días 0 (Pre-T) y 10 (PT). Las muestras fueron procesadas mediante la técnica de McMaster y los resultados de HPG se analizaron mediante el programa RESO para conocer el porcentaje de reducción de huevos y sus intervalos de confianza al 95% (IC95%). Resultados. El grupo BZ registró un 94% de reducción de HPG (IC95%= 87–97) y el grupo IMIDA registró 95% de reducción en el HPG (IC95%= 84-99). Conclusión. Se reporta por primera vez en México la presencia de poblaciones de Strongyloides sp. resistentes a benzimidazoles e imidazotiazoles en bucerros del trópico mexicano infectados naturalmente.

Resumen Aunque en la actualidad existe una gran preocupación por la contaminación y los posibles efectos sobre la salud que genera el uso frecuente de herbicidas, los estudios ambientales en los países tropicales son escasos, especialmente en Colombia. Por tanto, en el presente trabajo se evaluó la adsorción-desorción de diurón y ametrina en un suelo de Colombia (SC) y de España (SE). Los ensayos de adsorción-desorción se realizaron con moléculas de los herbicidas marcados con 14C, empleando la técnica batch equilibrium. En ambos suelos y para ambos herbicidas hubo un buen ajuste a las isotermas de Freundlich con R2 mayores a 0,99. Para diurón, en SE (Kfa= 12,82 ± 1,23) hubo mayor poder de adsorción frente a SC (4,56 ± 0,26). Por el contrario, para la ametrina se encontró un valor de Kfa = 6,47 ± 0,25 en SC y de 3,05 ± 0,08 en SE, mostrando mayor interacción con SC en comparación con SE. Para diurón se observó un grado de histéresis mayor en SC y para ametrina en SE, mostrando que la interacción de los dos herbicidas con los componentes de cada suelo es diferente dependiendo de su constitución mineralógica y su valor de pH. Abstract Although there is currently a great concern about pollution and the possible effects on health generated by the frequent use of herbicides, environmental studies in tropical countries are scarce, especially in Colombia. Therefore, in the present study, the adsorption-desorption of diuron and ametryn was evaluated in Colombian (SC) and Spanish soils (SE). The adsorption-desorption tests were carried out with molecules of 14C radiolabeled herbicides, using the batch equilibrium technique. In both soils and for both herbicides there was a good fit to the Freundlich isotherms with R2 greater than 0.99. For diuron, in SE (Kfa= 12.82 ± 1.23) showed greater adsorption affinity than SC soil (4.56 ± 0.26). In contrast, for ametryn we found Kfa values of = 6.47 ± 0.25 in SC and 3.05 ± 0.08 in SE, showing greater interaction with SC compared to SE. For diuron, a higher degree of hysteresis was observed in SC and for ametryn in SE, showing that the interaction of the two herbicides with the soil components is different depending on their mineralogical constitution and their pH value. Resumo Na atualidade, existe uma grande preocupação acerca da poluição e dos possíveis efeitos sobre a saúde gerados pelo uso freqüente de herbicidas. Além disso, os estudos ambientais em países tropicais são escassos, especialmente na Colômbia. No presente estudo, a adsorção-dessorção de diuron e ametrina foi avaliada em solo colombiano (SC) e solo espanhol (SE). Os testes de adsorção-dessorção foram realizados com moléculas de herbicidas marcados com 14C, utilizando a técnica batch equilibrium. Em ambos os solos e para os dois herbicidas houve um bom ajuste para as isotermas de Freundlich com R2 maior do que 0,99. Para o diuron, em SE (Kfa= 12,82 ± 1,23) houve maior poder de adsorção contra SC (4,56 ± 0,26). Em contraste, para a ametrina encontraram-se valores de Kfa de = 6,47 ± 0,25 em SC e 3,05 ± 0,08 em SE, mostrando a maior interação com SC quando se compara com SE. Para diuron, observou-se maior grau de histerese em SC e ametrina em SE, o que mostra que as interações destes dois herbicidas com os componentes de cada solo são diferentes dependendo da sua constituição mineralógica e seu valor de pH.

Resumen Introducción. Utilizar ensilaje de avena forrajera (Avena sativa L.) en la ganadería de leche en épocas deficitarias de alimento, permite mitigar pérdidas de biomasa por sequía en el trópico alto colombiano. Objetivos. 1) Determinar el rendimiento en materia seca (RMS) de cinco genotipos de avena forrajera y la estabilidad fenotípica y la calidad bromatológica de su ensilaje, y 2) evaluar la inclusión de ensilaje del genotipo AV25-T en dietas para ganado lechero. Materiales y métodos. Se realizaron en el trópico alto colombiano dos experimentos: 1) prueba de evaluación agronómica (octubre de 2016 a febrero de 2017) en un diseño de bloques completos al azar con cinco genotipos, ocho localidades y cuatro repeticiones; se determinó el rendimiento en materia seca (RMS) y en ensilaje los contenidos de proteína, fibra en detergente neutro (FDN) y nutrientes totales digestibles (NTD) y 2) estudio de respuesta animal (enero 2018) con la inclusión del genotipo AV25-T en dietas, en un diseño Crossover simple con dos factores: animal (5) y dietas (3); las dietas fueron: D1: solo pradera; D2: 35 % de ensilaje AV25-T + pastoreo y D3: 65 % de ensilaje AV25-T + pastoreo. Se determinó en la leche la producción, la proteína, la grasa y los sólidos totales, y en el animal el cambio de peso. Resultados. AV25-T presentó adaptación con el mayor RMS. La inclusión de ensilaje de AV25-T en la dieta animal, mostró un cambio significativo en el peso del animal (0,1 y 0,25 kg con D2 y D3), el rendimiento de leche (27,2 - 29,7 L/vaca/día con D3 y D2) y el contenido de grasa (3,2 - 3,9 % con D3 y D2), sin detrimento en proteína y sólidos totales. Conclusión. El uso del ensilaje de avena forrajera AV25-T permitió en vacas lecheras Holstein incrementos en el peso animal, el rendimiento de leche y el contenido grasa sin afectar la proteína y los sólidos totales. Abstract Introduction. The use of forage oat silage (Avena sativa L.) in dairy cattle in times of feed deficit, allows mitigating biomass losses due to drought in the Colombian high tropics. Objectives. 1) To determine the dry matter yield (DMY) of five forage oat genotypes and the phenotypic stability and the bromatological quality of their silage, and 2) to evaluate the inclusion of the AV25-T genotype silage in diets for dairy cattle. Materials and methods. In the Colombian high tropics two experiments were performed: 1) agronomic evaluation test (October 2017 and February 2018) in a randomized complete block design with five genotypes, eight locations, and four replicates; dry matter yield (DMY) and protein, neutral detergent fiber (NDF) and total digestible nutrients (TDN) contents in silage were determined, and 2) animal response study (January 2018) with the inclusion of the AV25-T genotype in diets, in a simple crossover design with two factors: animal (5) and diets (3); the diets were: D1: only meadow; D2: 35 % AV25-T silage + grazing, and D3: 65 % AV25-T silage + grazing. Milk yield, protein, fat, total solids, were determined in the milk, and weight change was determined in the animals. Results. AV25-T presented adaptation with the highest DMY. The inclusion of AV25-T silage in the animal diet showed a significant change in animal weight (0.1 and 0.25 kg with D2 and D3), milk yield (27.2 - 29.7 L/cow/day with D3 and D2), and the fat content (3.2 - 3.9 % with D3 and D2), without detriment in protein and total solids. Conclusion. The use of AV25-T forage oats in silage allowed increases in animal weight, milk yield, and fat content in Holstein dairy cows without affecting protein and total solids in milk.

Climate change, particularly rising temperature, is one of the important environmental problem facing the world today. This study aims to identify trends and patterns of temperature change in tropical and subtropical zones using a statistic model. Data were obtained from the climate research unit from 1973 to 2008, comprising 252 regions of 10° by 10° grid-boxes between latitudes 35° north and south. The data were filtered with a second order autoregressive process to remove autocorrelations between temperature lags. Factor analysis was used to classify monthly average temperature anomalies into larger regions by taking into account the correlation between adjoining regions. Simple linear regression models were then fitted to the data within these larger regions. The result showed that the temperatures in these 15 larger regions have increased the most (by at least 0.065°C per decade) in the North Atlantic Ocean and the central and the north of Africa. Lower increases (0.045–0.064°C per decade) occurred in Southeast Asia, the Indian Ocean and the North Pacific Ocean.

This paper presents a selected, not exhaustive, description of lightning research in Colombia over time, based on natural observatories for experimentation and measurement; and introduces the DABEIBA Lightning Research Center as a new institutional cooperation to concentrate several instruments such as Lightning Mapping Array - LMA, high speed cameras, high energy detectors, by different scientific parties in a single area for tropical lightning research. © 2018 IEEE.

14th IWA Specialized Conference on Small Water and Wastewater Systems, Nantes, FRA, 22-/10/2017 - 26/10/2017; International audience; Wastewater management in the French Overseas Territories (FOT) are lagging behind France mainland and both French and European regulations. Municipalities are characterized by resources weakness in terms of self-financing capacities as well as skilled human resources for maintenance. Treatment technologies selection and choices made for systems designs are suffering from missing knowledges on their operation in tropical conditions. Implementing a wastewater treatment plant (WWTP) in tropical conditions requires feedbacks on technologies behaviour under the tropics and knowledge of raw wastewater in order to adjust system design. Consequently a study has been conducted to compare treatments technologies performances, in real operating conditions, in order to optimize public investment by implementing suited systems to local constraints. The study has been focused on the five FOT (Martinique, Guadeloupe, Mayotte and La Réunion islands and French Guyana) and treatment plant capacities between 20 and 2 000 people equivalent (p.e.). Comparison of raw wastewater from small communities in the FOT and in French rural areas shows no major differences in terms of average concentrations. Upper bounds of the ranges of variations suggest that sometimes, highly concentrates influents reach the WWTP. The p.e. pollutants production has been evaluated at 60/130/65/17/2.5 g/d for small communities in FOT for BOD5/COD/TSS/KN/TP respectively. Performances comparison on the 4 treatments technologies the more implemented (activated sludges, natural ponds, rotating biological contactor, and vertical flow constructed wetland) gives important feedbacks: • Activated sludge is the main technology implemented in the FOT (70%), but the least reliable. Sludge leakages are noticeable on 10% of the campaigns. Lack of nitrification observed suggests maintenances troubles. • At low loads, algae prevent ponds from achieving French minimal regulation objectives for the removal rates. • Settling troubles have been identified on RBC. • With all the regulatory objectives fulfill with a 90-95% frequency, VFCW is the most reliable technology. It requires space and can't be implemented everywhere, even if tropical design has reduces the footprint (0.8 m²/p.e.). VFCW can reach high level performances (125 mgCOD/L), but shows also its limits (70% of NTK removal achieved by 75% of the sampling campaigns). Designs adjustments like unsaturated/saturated system or higher filtration layer enable adaptation to different objectives.

Intensification of agricultural systems in sub-Saharan Africa (SSA) is considered a pre-condition for alleviation of rural poverty. Conservation Agriculture (CA) has been promoted to achieve this goal, based on three principles: minimum tillage, soil surface cover, and diversified crop rotations. CA originated in regions where fertilizer is commonly used and crop productivity is high, ensuring an abundance of crop residues. By contrast, crop yields are generally low in SSA and organic residues in short supply and farmers face competing demands for their use. Since minimal tillage without mulch commonly results in depressed yields, the use of fertilizer to enhance crop productivity and organic residue availability is essential for smallholder farmers to engage in CA. This is especially true since alternative ways to increase organic matter availability have largely failed. A case study from Kenya clearly demonstrates how fertilizer increases maize stover productivity above thresholds for minimal initial soil cover required for initiating CA (about 3 tonne ha −1 ). We conclude that strategies for using CA in SSA must integrate a fourth principle – the appropriate use of fertilizer – to increase the likelihood of benefits for smallholder farmers.

Metadata only record This paper studies the recent boom and bust in Vietnam's coffee economy. Data from smallholder coffee farms in the Central Highlands are used to examine responses to a drop in producer coffee prices. A multinomial logistic regression model is used to identify several factors associated with four specific patterns observed among coffee farmers: no response to price change, reductions in use of purchased inputs, changes in crop mix, and responses aimed at enhancing liquidity through off-farm work or borrowing. Patterns of response are shown to have differed systematically across sub-groups of smallholders. Policy implications raised by the findings are discussed. SysCoor-5 (Policy and Governance)

A considerable proportion of the 200 million hectares of the Brazilian Cerrado is suitable for annual crops but little is known about the effects of tillage on the C dynamics of Cerrado soils. We evaluated the role of two representative Cerrado Oxisols (350 and 650 g clay kg−1) as sources or sinks of atmospheric C when managed under three tillage systems (conventional tillage (CT), reduced tillage (RT), and no-till (NT)) in 8- and 5-year long-term experiments. A literature review was also carried out and the mean C sequestration rates in no-till soils of tropical and subtropical regions of Brazil were calculated and compared with values for soils from temperate regions of the world. The original C stocks in 0–20 cm layer of soils under native Cerrado were higher in the clayey (54.0 Mg ha−1) than in the sandy clay loam soil (35.4 Mg ha−1), suggesting a higher physical stability of organic matter associated with variable clay minerals in the clayey Oxisol. The original C stocks of the native Cerrado soils appear not to have decreased after 23 years of conventional tillage in the sandy clay loam Oxisol, except when the soil had been subjected to erosion (15% loss of C), or after 25 years in the clayey Oxisol. Compared to conventionally tilled soil, the C stocks in no-till sandy clay loam Oxisol increased by 2.4 Mg ha−1 (C sequestration rate = 0.30 Mg ha−1 year−1) and in the clayey Oxisol by 3.0 Mg ha−1 (C sequestration rate = 0.60 Mg ha−1 year−1). The mean rate of C sequestration in the no-till Brazilian tropical soils was estimated to be 0.35 Mg ha−1 year−1, similar to the 0.34 Mg ha−1 year−1 reported for soils from temperate regions but lower than the 0.48 Mg ha−1 year−1 estimated for southern Brazilian subtropical soils. Considering the large area (about 70 million hectares) of the Cerrado which is currently used and potentially available for cropland, the adoption of no-till systems could turn the Cerrado soils into a significant sink for atmospheric C and contribute to the mitigation of global climate change.

Since the early 1990s community-based natural resource management (CBNRM) has become a mantra of sustainable development, which has been broadly embraced by national leaders and policy-makers in Africa, as well as aid bureaucrats and technical specialists in donor countries. Its dissemination to local communities, however, has turned out to be a rather controversial process. On the basis of two case studies this article assesses the extent to which the new approach has been adopted in Mozambique, and the conditions on which it has been accepted by local communities. The results indicate that the CBNRM model cannot be considered independently of the local political context, even though this aspect has been largely neglected. Devolution of full authority to local institutions is also a crucial issue. Restrictions on the use of natural resources are acceptable to the local population, but only if they are compatible with local livelihood strategies. Copyright © 2004 John Wiley & Sons, Ltd and ERP Environment.

Metadata only record Irrigated rice fields are temporary wetland agro-ecosystems, managed with a variable degree of intensity. A survey was carried out in Sri Lanka to document the overall biodiversity associated with this unique agro-ecosystem, using a combination of sampling techniques to document different groups of fauna and flora. The total number of biota recorded and identified from the rice field ecosystem during the entire study period consisted of 494 species of invertebrates belonging to 10 phyla and 103 species of vertebrates, while the flora included 89 species of macrophytes, 39 genera of microphytes and 3 species of macrofungi. Of the total species documented, 15 species of invertebrates and one weed species are new records to Sri Lanka. Arthropods were the dominant group of invertebrates ( 405 species), of which 55 species were rice pest insects, and 200 species were natural enemies of pest insects. The fauna and flora recorded from the rice field were observed to follow a uniform pattern of seasonal colonization and succession during successive rice cultivation cycles. The biodiversity of the irrigated rice agro-ecosystem interests both agroecologists and conservation biologists. Therefore, the integrated efforts of these two groups can result in the formulation of strategies based on biodiversity as an organizing principle in the sustainable management of the rice field agro-ecosystem.

Metadata only record This article reports on the incremental cost of carbon sequestration in forestry and agroforestry systems, calculating the potential and cost of carbon storage with the tropical tree species Paraserianthes falcataria. The authors use an economic model in the Manupali Watershed of the Bukidnon Province in the Philippines that takes into account the opportunity cost of converting land from annual cropping systems to tree-based systems. They find that the cost of storing carbon through reforestation ranges from $3.30 / ton for conversion of fallowed land to $62.50 / ton for conversion of highly productive crop land. They suggest that the lower marginal cost of conversion to agroforesty supports a preference towards agroforestry systems rather than pure forestry. BA-1 (SANREM Research in Southeast Asia)

Metadata only record In this paper we investigate determinants of land use decisions made by farmers in an upland area of the Philippines. Our goal is to quantify land use responses to economic signals, especially agricultural prices, and thereby to shed light on the impacts of policies affecting such prices. We use a decade-long panel of farm-level data on agricultural practices and prices. We find that prices do indeed matter to upland land use decisions, and thus that policy reforms, such as those required by accession to the WTO, may be influential if indirect determinants of land use patterns in these politically and environmentally sensitive areas. BA-1 (SANREM Research in Southeast Asia)

The problem of poverty in Africa was often discussed in terms of the agro-ecological specifics and the internal social relations of societies, production systems and economies. It appeared necessary, therefore, for states and international organizations to intervene. Because poverty was identified with production constraints, such interventions took the form of technological transfer in agriculture. Later, as agro-ecological constraints became more widely perceived, and supposedly "fragile" ecosystems were believed to be under threat from population growth and other factors, emphasis shifted to "environmental sustainability". As with the new technologies, so with sustainable natural resource management, it was often assumed that the new knowledge must come from outside, or from "science", and must be promoted against the natural "conservatism" of smallholders by whatever means necessary--from coercion at one extreme to "participation" at the other. Recently there has been much movement away from such stereotypical positions towards more subtle and varied statements of the problem. However, I believe there is still a lacuna with respect to the autonomy of the smallholder in the "fight against poverty". Intervention is still the name of the game, and receives far more attention than the resources or achievements of poor people themselves. Analyses of long-term trends in the management of resources at the village, regional and national levels in dryland Africa suggest that African farmers have made considerable achievements in the face of a trying environment. An understanding of this long-term trend may provide a better framework for the diagnosis of current problems and the formulation of future policy on poverty and livelihoods in the drylands.

An appreciation of the dynamism of the links between soil resources and society provides a platform for examining food security over the next 50 years. Interventions to reverse declining trends in food security must recognize the variable resilience and sensitivity of major tropical soil types. In most agro-ecosystems, declining crop yield is exponentially related to loss of soil quality. For the majority smallholder (subsistence) farmers, investments to reverse degradation are primarily driven by private benefit, socially or financially. “Tragedy of the commons” scenarios can be averted by pragmatic local solutions that help farmers to help themselves.

Community Based Conservation (CBC) has become the catch-all solution to the social and ecological problems plaguing traditional top-down, protectionist conservation approaches. CBC has been particularly popular throughout Africa as a way to gain local support for wildlife conservation measures that have previously excluded local people and their development needs. This article shows that, despite the rhetoric of devolution and participation associated with new CBC models, conservation planning in Tanzania remains a top-down endeavour, with communities and their specialized socio-ecological knowledge delegated to the margins. In addition to the difficulties associated with the transfer of power from state to community hands, CBC also poses complex challenges to the culture or institution of conservation. Using the example of the Tarangire-Manyara ecosystem, the author shows how local knowledge and the complexities of ecological processes challenge the conventional zone-based conservation models, and argues that the insights of local Maasai knowledge claims could better reflect the ecological and social goals of the new CBC rhetoric.

Metadata only record In order to assess the influence of change in land use on microbial activity, soils from the A horizon of two major wet tropical forests (moist deciduous (MD) and semi-evergreen (SE)) and two adjacent plantations of padauk (Pterocarpus dalbergioides) and teak (Tectona grandis) established by clearing portions of these forests were studied for various microbial indices and their interrelationships. The two sites revealed marked differences in soil organic matter and microbial properties. The levels of microbial biomass C, biomass N, basal respiration, ergosterol and adenylates (ATP, AMP, ADP) at the forest sites significantly exceeded the corresponding values at the plantation sites, indicating greater microbial activity under the former. Among the ratios of different microbial properties, the ergosterol-to-biomass C ratio and mean metabolic quotient (q(CO2)) were significantly higher under the forests suggesting a marked decline due to deforestation and cultivation. The ergosterol-to-biomass C ratio further indicated that the fungi, especially at the plantation sites, have very low ergosterol content. The ratios of biomass N-to-total N, biomass C-to-N, biomass C-to-organic C, and ATP-to-biomass C, however, did not vary significantly between the forest and plantation sites. On the contrary, adenylate energy charge (AEC) levels at the forest sites were consistently higher than 8.0, reflecting greater microbial proliferation at these sites. Overall, our study indicated that on a long-term basis, deforestation and cultivation significantly reduced microbial activity due to decline in available organic matter/substrate levels. © 2003 Elsevier B.V. All rights reserved.

Metadata only record While conservation activities are underfunded almost everywhere, the gap between current expenditure and what is needed is particularly extreme in the tropics where threatened species and habitats are most concentrated. We examine how to bridge this funding gap. Firstly, we try to identify who in principle should pay, by comparing the spatial distribution of the costs and the benefits of tropical conservation. The immediate opportunity costs of conservation often exceed its more obvious, management-related costs, and are borne largely by local communities. Conversely, we argue that the greatest benefits of conservation derive from ecological services, and from option, existence, and bequest values; these are often widely dispersed and enjoyed in large part by wealthier national and global beneficiaries. We conclude that the gap in funding tropical conservation should be borne largely by national and especially global communities, who receive most benefit but currently pay least cost. In the second part of the paper we review recent developments in order to examine how in practice increased funding may be raised. There are many growing and novel sources of support: private philanthropy, premium pricing for biodiversity-related goods via certification schemes, and the development of entirely new markets for environmental services. Despite their potential, we conclude that the principal route for meeting the unmet costs of tropical conservation will have to be via governments, and will inevitably require the transfer of substantial resources from north to south. This will be enormously difficult, both politically and logistically, but without it we believe that much of what remains of tropical nature will be lost. PES-1 (Payments for Environmental Services Associate Award)

Metadata only record The increasing attention paid to local soil knowledge in recent years is the result of a greater recognition that the knowledge of people who have been interacting with their soils for a long time can offer many insights about the sustainable management of tropical soils. This paper describes two approaches in the process of eliciting local information. Case studies show that there is a consistent rational basis to the use of local indicators of soil quality and their relation to improved soil management. The participatory process used is shown to have considerable potential in facilitating farmer consensus about which soil-related constraints should be tackled first. Consensus building is presented as an important step prior to collective action by farming communities in integrated soil management at the landscape scale. Taking advantage of the complementary nature of local and scientific knowledge is highlighted as an overall strategy for sustainable soil management.

Innovation by farmers in land husbandry was the focus of the project Promoting Farmer Innovation (PFI), which was operational in Kenya, Tanzania and Uganda from 1997 to 2001. One of the project's final activities was to document best-bet innovations. It was decided to make use of a questionnaire available under the World Overview of Conservation Approaches and Technologies (WOCAT) to collect data on a selection of these technologies. Data were fed back into WOCAT's global database. Eighteen technical initiatives were recorded in this way, and the findings added to existing data and in-house knowledge. This information was analysed and a technical report produced (Mutunga and Critchley, 2001). The technologies included turning gullies into gardens, digging planting pits for millet and sorghum and harvesting water from roads. Each combined aspects of land conservation with improved plant production. While several required relatively high initial labour input, all were considered economically beneficial by the farmers. Adoption by other farmers was generally rapid, partially as a result of farmer to farmer visits under PFI. The value of the PFI-WOCAT exercise was not restricted to recording and disseminating information, however. It was also a test of the utility of WOCAT within a project. There were a number of interesting findings. Although those who filled the questionnaires found it an onerous task, they felt that they learned a good deal as they went through the process. One of the main conclusions was that the questionnaire could be a very valuable template to help guide internal monitoring and evaluation, if used from the start of a project intervention. Copyright © 2002 John Wiley & Sons, Ltd.

Metadata only record This paper provides a survey of 'first wave' economic studies of tropical deforestation and land use. These studies of tropical forest land conversion are generally at the cross-country level. We also conduct a synthesis cross-country analysis of tropical agricultural land expansion. The results show that agricultural development is the main factor determining land expansion, but institutional factors have an important influence. Income effects tend to vary from region to region, and do not always display an 'Environmental Kuznets Curve' relationship. This paper also provides a review of the more recent 'second wave' economic studies of tropical deforestation that model and analyse the economic behaviour of agricultural households, timber concessionaires and other agents within tropical forest countries who affect deforestation through their land use decisions. Further work in this area requires more country-level and local case studies into tropical deforestation and land use.

Objective. Characterize the follicular dynamics and luteal growth and regression pattern of multiparous (MB) and heifer (BH) Murrah buffaloes in Colombian tropical conditions. Material and methods. Ten MB and ten BH were synchronized with a progesterone-releasing intravaginal device. No artificial insemination was performed during the estrous and daily ultrasound examinations were performed 15 days later to determine the number and diameter of the structures present in both ovaries in the subsequent natural estrous cycle. The Student’s T test was used to evaluate differences between MB and BH. All data are presented as mean ± standard deviation. Results. The length of the estrous cycle was 22.00±4.50 days for MB and 22.00±2.70 days for BH. Follicular growth occurs in one (n=1; 5.89%), two (n=14; 82.35%) or three waves (n=2; 11.76%). The first wave initiated the day after ovulation with the recruitment of 8.33±2.06 and 10.00±2.72 follicles in MB and BH, while the second wave started on day 11.00±2.00 and 10.50±2.82, presenting 8.37±2.26 and 8.00±1.51 follicles. The third wave began on day 16.21±3.10 showing 6.50±1.70 follicles, only BM had three waves. The maximum luteal diameter was 19.58±4.16 mm and 17.74±3.32 mm respectively. There were no significant differences between the groups for these variables. Conclusions. These results show that the follicular development in buffaloes occurs in waves, where two waves is the most common pattern, as previously reported by other authors.

Objective. Characterize the follicular dynamics and luteal growth and regression pattern of multiparous (MB) and heifer (BH) Murrah buffaloes in Colombian tropical conditions. Material and methods. Ten MB and ten BH were synchronized with a progesterone-releasing intravaginal device. No artificial insemination was performed during the estrous and daily ultrasound examinations were performed 15 days later to determine the number and diameter of the structures present in both ovaries in the subsequent natural estrous cycle. The Student's T test was used to evaluate differences between MB and BH. All data are presented as mean ± standard deviation. Results. The length of the estrous cycle was 22.00±4.50 days for MB and 22.00±2.70 days for BH. Follicular growth occurs in one (n=1; 5.89%), two (n=14; 82.35%) or three waves (n=2; 11.76%). The first wave initiated the day after ovulation with the recruitment of 8.33±2.06 and 10.00±2.72 follicles in MB and BH, while the second wave started on day 11.00±2.00 and 10.50±2.82, presenting 8.37±2.26 and 8.00±1.51 follicles. The third wave began on day 16.21±3.10 showing 6.50±1.70 follicles, only BM had three waves. The maximum luteal diameter was 19.58±4.16 mm and 17.74±3.32 mm respectively. There were no significant differences between the groups for these variables. Conclusions. These results show that the follicular development in buffaloes occurs in waves, where two waves is the most common pattern, as previously reported by other authors. Objetivo. Caracterizar la dinámica folicular y el patrón de crecimiento y regresión del cuerpo lúteo de búfalas multíparas (BM) y búfalas novillas (BN) de la raza Murrah en condiciones del trópico colombiano. Materiales y métodos. Diez BM y diez BN fueron sincronizadas con dispositivo intravaginal de liberación de progesterona. No se realizó la inseminación artificial al momento del celo y 15 días después se inició el seguimiento ultrasonográfico para determinar el número y diámetro de las estructuras presentes en ambos ovarios en el subsecuente ciclo estral natural. Las diferencias entre BM y BN se evaluaron con pruebas T. Los datos se presentan como media ± desviación estándar. Resultados. La duración del ciclo estral fue de 22.00±4.50 y 22.00±2.70 días en BM y BN. El crecimiento folicular ocurrió en una (n=1; 5.89%), dos (n=14; 82.35%) o tres (n=2; 11.76%) ondas. La primera onda inicio el día siguiente a la ovulación con el reclutamiento de 8.33±2.06 y 10.00±2.72 folículos en BM y BN, mientras que la segunda onda inicio el día 11.00±2.00 y 10.50±2.82 con 8.37±2.26 y 8.00±1.51 folículos. La tercera onda inicio el día 16.21±3.10 con 6.50±1.70 folículos, sólo BM presentaron tres ondas. El diámetro máximo luteal fue de 19.58±4.16 mm y 17.74±3.32 mm. No se observaron diferencias significativas entre los grupos para estas variables. Conclusiones. Los resultados muestran que el desarrollo folicular de las búfalas se dio en ondas, siendo dos ondas el patrón más común, similar a lo reportado por otros autores.

This paper documents the events leading to the imminent collapse of an attempt to rehabilitate a degraded ecosystem in central Tanzania, focusing on the consequences of the failure to systematically monitor socio-economic and environmental indicators. A decision was taken in 1979 to evict all grazing livestock from a 1200 km2 semi-arid area, the so-called Kondoa Closed Area, in central Tanzania due to their destructive effect on contour ridges and bunds that had been constructed in an attempt to arrest land degradation. Although the closure was successful in that the vegetation quickly regenerated and soil erosion was arrested, the evictions resulted in severe hardship for the agro-pastoralists in the area. As a result, it was decided a decade later to allow the reintroduction of cattle on condition that they were totally confined and were of improved dairy breeds. Although performance and economic data have generally been positive, the top–down approach to the introduction of the cows, the lack of baseline data, followed by the withdrawal of external funding, have resulted in increased illegal free-grazing and the near collapse of the attempt to convert a degraded ecosystem to sustainable use. It is concluded that the probable collapse of the ecosystem in the Kondoa Closed Area is a result of the initial top–down approach to the introduction and implementation of the project, inadequate monitoring of socio-economic and environmental indicators, and ultimately to the withdrawal of donor funding.

The tropical wetland environments of northern Australia have ecological, social, cultural and economic values. Additionally, these areas are relatively pristine compared to the many other wetland environments in Australia, and around the world, that have been extensively altered by humans. However, as the remote northern coastline of Australia becomes more populated, environmental problems are beginning to emerge that highlight the need to manage the tropical wetland environments. Lack of information is currently considered to be a major factor restricting the effective management of many ecosystems and for the expansive wetlands of the Northern Territory, this is especially the case, as these areas are generally remote and inaccessible. Remote sensing is therefore an attractive technique for obtaining relevant information on variables such as land cover and vegetation status. In the current study, Landsat TM, SPOT (XS and PAN) and large-scale, true-colour aerial photography were evaluated for mapping the vegetation of a tropical freshwater swamp in Australia's Top End. Extensive ground truth data were obtained, using a helicopter survey method. Fourteen cover types were delineated from 1:15 000 air photos (enlarged to 1:5000 in an image processing system) using manual interpretation techniques, with 89% accuracy. This level of detail could not be extracted from any of the satellite image data sets, with only three broad land-cover types identified with accuracy above 80%. The Landsat TM and SPOT XS data provided similar results although superior accuracy was obtained from Landsat, where the additional spectral information appeared to compensate in part for the coarser spatial resolution. Two different classification algorithms produced similar results.

Metadata only record The experience in coastal management in the tropics that is presented in this special issue is considered in light of other coastal management initiatives worldwide. The major challenges confronting those working to promote cross-sectoral, participatory approaches to the management of coastal areas are discussed. Emerging conceptual frameworks are considered. Several factors critical to the design of coastal management projects and programs are identified. The article concludes with a reflection on priorities for furthering the practice of coastal management in the next decade.

Soil degradation due to loss of forest cover, water erosion and shifting cultivation LTRA-11 (CAPS among tribal societies in India and Nepal)

Conservation agriculture (CA) is increasingly promoted in Africa as an alternative for coping with the need to increase food production on the basis of more sustainable farming practices. Success with adopting CA on farms in Africa has been limited, despite more than two decades of research and development investments. Through analyzing past and on-going CA experiences in a set of case studies, this paper seeks to better understand the reasons for the limited adoption of CA and to assess where, when and for whom CA works best. CA is analyzed and understood within a framework that distinguishes the following scales of analysis: field, farm, village and region. CA has a potential to increase crop yields in the fields, especially under conditions of erratic rainfall and over the long-term as a result of a gradual increase of overall soil quality. The impact on farm income with the practice of CA on some fields of the farm is far less evident, and depends on the type of farm. The lack of an immediate increase in farm income with CA explains in many cases the non-adoption of CA. Smallholders have often short-term time horizons: future benefits do not adequately outweigh their immediate needs. Another key factor that explains the limited CA adoption in mixed crop-livestock farming systems is the fact that crop harvest residues are preferably used as fodder for livestock, preventing their use as soil cover. Finally, in most case studies good markets for purchase of inputs and sale of produce – a key prerequisite condition for adoption of new technologies – were lacking. The case studies show clear evidence for the need to target end users (not all farmers are potential end user of CA) and adapt CA systems to the local circumstances of the farmers, considering in particular the farmer's investment capacity in the practice of CA and the compatibility of CA with his/her production objectives and existing farming activities. The identification of situations where, when and for whom CA works will help future development agents to better target their investments with CA.

Metadata only record The nutrient Phosphorous (P) can be available in forms not available for plant uptake, and it is often a limiting factor in tropical crop production. However, certain plants are particularly efficient at extracting phosphorous. These plants can be effective cover crops because they improve phosphorous availability and uptake for the subsequent crop. This study examines the ability of seven different crops to improve phosphorous availability for farmers in Haiti’s Central Plateau. Surface soil from the Central Plateau was air dried and shipped to researchers in the US, where treatments of black bean (Phaseolus sp.), chickpea (Cicer arietinum L.), cowpea (Vigna unguiculata [L.] Walp.), grain sorghum (Sorghum bicolor [L.] Moench), lablab, pigeon pea, and velvet bean were applied in a controlled-environment chamber. After forty-nine days the plants were uprooted and samples of rhizosphere and bulk soil were analyzed. Phosphorous uptake did not differ among the seven species studied. However, researchers found that P uptake positively correlated with rhizosphere P and dry weight. Velvet bean was found to have the high quantity of dry mass, a positive characteristic for a cover crop. LTRA-6 (A CAPS program for the Central Plateau of Haiti)

This presentation describes a study conducted by the East Africa SANREM team which examines the following questions: (1) How do alternative tillage treatments that eliminate plows impact soil quality? (2)How do alternative cropping systems that include cover crops impact soil quality? (3) How do combined alternative cropping and tillage systems affect soil quality? LTRA-10 (CAPS for smallholder farms in eastern Uganda and western Kenya)

This poster presents a study to evaluate the impact oftillage: conventional tillage (CT), minimum tillage (MT) and notill(NT) combined with 3 cropping systems: intercrop, relay andstrip system on: (i.) Total and labile SOC and N pools and (ii.) Bulk density (BD), penetration resistance (PR) and water in eastern Uganda and western Kenya. LTRA-10 (CAPS for smallholder farms in eastern Uganda and western Kenya)

Metadata only record This paper assesses the effects of slope length (10-60m) and tillage method (conventional versus no-till) on soil chemical properties and nutrient loss in runoff water, evaluating both aggregate seasonal effects and month-by-month variation.

The farm-level economics of conservation agriculture (zero tillage, mulching and crop rotation) are described, reviewed and modelled. The economics are defined broadly to include not just short-term financial benefits and costs, but also the whole-farm management context, constraints on key resources such as labour and capital, risk and uncertainty, interactions between enterprises, and time-related factors, such as interest rates and the urgency of providing for the farm family. A wealth of evidence shows that these economic factors and variables related to them have significant influences on farmers’ decisions about adoption of conservation agriculture. Literature on the farm-level economics of conservation agriculture for resource-poor farmers is reviewed. There is not a large body of high-quality relevant studies. Those that have been published highlight that the economics are highly heterogeneous and need to be considered on a case-by-case basis. Their results tend to indicate that it would be profitable to adopt conservation agriculture or components of it (although not in all cases). This contrasts with disappointing adoption in many of the regions of interest. Potential reasons for this disparity are discussed. A general model of the farm-level economics of conservation agriculture and its components is presented, and used to illustrate influences on the overall economic attractiveness of conservation agriculture. Key factors that would tend to discourage adoption in situations that otherwise look favourable include: the opportunity cost of crop residues for feed rather than mulch, the short-term reduction in yields under zero tillage plus mulching in some cases, combined with short planning horizons and/or high discount rates of farmers, farmer aversion to uncertainty, and constraints on the availability of land, labour and capital at key times of year. Good quality economic analysis should be used more extensively to guide research and extension in this area, particularly in relation to the targeting of effort, and adaptation of the system to suit local conditions.

Because women share much of the burden of agricultural production, it is critical to examine the impact that agricultural innovations will have on the distribution of labor between genders. Conservation agriculture has been identified as an innovation to improve agricultural production in the Mid-hills of Nepal by reducing erosion and increasing soil organic matter. This paper identifies the gendered distribution of agricultural labor in three Chepang tribal villages of central Nepal, in order to estimate the changes in labor required by conservation agriculture interventions, and assess the implications of labor shifts with respect to the potential for adoption of conservation agriculture practices. Three tribal villages in Chepang were surveyed, with the male and female heads for each household questioned separately to assess the labor hours from each gender for cropping activities under conventional and conservation agricultural systems. Field experiments were also conducted to determine labor hours necessary for the adoption of conservation agriculture practices. Conservation agriculture was found to increase women’s share of agricultural labor, with a greater increase for intercropping with conventional tillage than for intercropping and minimal tillage. LTRA-11 (CAPS among tribal societies in India and Nepal)

Metadata only record The publication provides 25 summaries of the impacts on climate change on 22 natural, agroforestry, forest and water resources. Each summary explains how each resource is valuable, how each is threatened by climate change and how individuals who rely upon that resource are at risk for socio-economic disruption. It remains largely unknown how climate change will impact important natural resources and the strength and patterns of diseases, weeds, and pests. It remains to be discovered how food security will be impacted by climate change-induced variability in temperature, atmospheric carbon dioxide concentrations, and rainfall. The summaries in this document seek to clarify these concerns.

Metadata only record During this time of environmental change, the management of natural resources may be our wisest pursuit; specifically, where it relates to international agricultural development. This research has studied the potential for agricultural development in the tribal villages of Kendujhar, one of the poorest districts in the East Indian state of Odisha. With a population primarily consisting of smallholder farming systems characterized by poor soil fertility and moisture retention, limited irrigation, and susceptibility to erosion, agricultural productivity in this region has been adversely impacted. As such, this study’s research evaluates the impact of conservation agriculture (CA) practices in these villages. This dynamic approach of CA focuses on two interventions: minimum tillage and intercropping. Primary data collection through face-to-face interviews was completed to establish agricultural household baselines in the district, while a field experiment was used to assess the productivity of the two CA practices. Maize/cowpea intercropping and minimum tillage treatments were established to determine differences in yields and labor requirements. The results showed that with a maize/cowpea intercrop, the greatest returns occur when we consider labor without the opportunity for off-farm employment. On the other hand, if labor has opportunity for off-farm employment, it is more economical to work off-farm; however, this applies primarily to young male household members who have greater opportunity for employment. The implications for gender, in terms of labor, are such that with CA, male labor reduces while female labor increases. Based on the results, there are multiple recommendations for agribusiness and policy-makers: (1) assist farmers with input and seed subsidies and access to credit for CA adoption to enhance yields, increase returns, and improve food security; (2) increase extension efforts for farmer education on the benefits of CA; and (3) train farmers on the benefits of high-yielding commercial seeds and improved farming practices. LTRA-11 (CAPS among tribal societies in India and Nepal)

This presentation introduces UH staff and students to LIBIRD and Tribhuan University, both in Nepal. It also introduces the farming conditions and crops at each study site. LTRA-11 (CAPS among tribal societies in India and Nepal)

This poster presents the results from implimenting CAPS methods in tribal villages located in Odessa State, India. It gives socio-economic data for households in the study villages as well as project objectives and methods. It presents the results of the experimental plots and socio-economic survey data. Finally, it gives conclusions and implications for future research. LTRA-11 (CAPS among tribal societies in India and Nepal)

Small-holder farms in rural India struggle with reduced maize yields due to traditional farming methods. The introduction of modern conservation agriculture practices can provide higher yields and household income while boosting soil productivity. This poster abstract presents the results of CAPS implementation on experimental plots in tribal villages located in the Indian state of Odessa. LTRA-11 (CAPS among tribal societies in India and Nepal)

A presentation presenting detailed steps in conducting AHP to determine tribal Indian farmers' preference for cropping strategies that improve profit, labor savings, yield, or soil quality. These strategies are in pursuit of the overall goal of improving income. This presentation served as both an explanation of AHP and a tool for administering AHP surveys in a classroom setting. LTRA-11 (CAPS among tribal societies in India and Nepal)

This presentation introduces the SMARTS project and gives 1st year results of CAPS implementation in Odessa, India. The presentation uses yield data as well as socio-economic analysis to develop conclusions and implications for future research. LTRA-11 (CAPS among tribal societies in India and Nepal)

Metadata only record "This report describes a study undertaken to identify areas that are food insecure and vulnerable to the

En la búsqueda de nuevas opciones forrajeras para alimentación animal en el trópico, se evaluó una colección de Tadehagi triquetrum con 84 accesiones suministradas por la Unidad de Recursos Genéticos del Centro Internacional de Agricultura Tropical – CIAT, en suelos ácidos del norte del Cauca. La evaluación se realizó en la subestación Experimental CIAT Quilichao, ubicada en el Municipio de Santander de Quilichao, Departamento del Cauca a 3º 06´ de latitud norte y 76º 31´de longitud oeste, a una altitud de 990 m.s.n.m., con una temperatura promedio de 23º C. Se utilizó un diseño experimental de bloques completos al azar con tres repeticiones para evaluación agronómica y calidad; además, una cuarta repetición para caracterización morfológica. Se sembraron en hileras 5 plantas por accesión y repetición para la evaluación agronómica, con una distancia entre plantas de 1 m y 1.5 m entre accesiones. El área de muestreo comprendió las tres plantas centrales. En la repetición 4, por disponibilidad de semilla, se sembró 3 plantas por accesión con el mismo patrón de siembra. //Abstrac: Searching new options for tropical animal feed it was evaluated a Tadehagi triquetrum collection with 84 accessions supplied by Unidad de Recursos Genéticos del Centro Internacional de Agricultura Tropical – CIAT, in North Cauca acid soils. Evaluation was made in CIAT Quilichao experimental substation located in the Municipality of Santander de Quilichao, department of Cauca, at 3º 06´ north latitude and 76º 31´west longitude, an 990 m.a.s.l altitude and 23 °C mean temperature. It was used a completely randomized blocks experimental design with three replications for agronomic evaluation and quality and a fourth additional for morphological characterization. It was planted in rows five plants by accession and replication for agronomic evaluation, with 1 m of plants distance and 1.5 among accessions. The sampling area was formed by the three central plants. In replication 4, because seed availability, it was planted 3 plants by accession with the same planting pattern. Maestría