Effects of daylength and soil humidity on the flowering of coffee coffea arabica l. in colombia.

Coffee flowering data were analyzed in order to explore the effect of two environmental variables that have been considered relevant for this process. Pre-anthesis stage flowers were counted in coffee leaf-rust resistant crops at eight experimental stations (between 2°N and 11°N). Likewise, climatic data were taken to generate a humidity soil index, whereas day longitude data were taken from the Smithsonian Meteorological Tables. Flowering data were compared with a sunshine index to understand better the effect of light on flowering. This data (flowering, soil humidity index and day length) were expressed in a monthly scale and analyzed using linear regression and cross-correlation functions. The main results show that there is a significant correlation between short days and high flowerings, whereas soil humidity (dry months) are related to the phenomenon, but to a lesser extent

Sistema integrado de recomendación y diagnosis: una alternativa para la interpretación de resultados del análisis foliar en café

Con el fin de proveer otras alternativas de interpretación de resultados del análisis foliar en café, diferente a la tablade contenido "normal", se aplicó la metodología SIRD (Sistema Integrado de Recomendación y Oiagnosis)5 a la información proveniente de un experimento con N-P-K,factorial de 33 realizado en CENICAFE, Colombia. Los nutrimentos incluidos en el análisis foliar y su interpretación fueron N, P, K, Ca, Mg, Mn, Fe y B. Por primera vez, con fines de diaqnóstico , se obtuvo la tabla de normas SIRD para café con base en una producción de 2.750 Kg de c.p.s/ha queincluye 1036 análisis foliares, para un total de 28 relaciones binarias de cociente entre los 8 nutrimentos mencionados. SI RO presentó la interpretación de resultados del análisisfoliar en forma más clara que los elaborados con la Tabla de Contenido "normal", pues agrupó en orden de importancia en las necesidades del cultivo, todos los elementos nutritivos estudiados. Los diagnósticos elaborados mediante SIRD fueron válidos, pues al seguir su recomendación se observó respuesta tanto en la composición interna de la planta como en la producción de café. El calcio, según el enfoque SIRD, se mostró como un elemento potencialmente limitante de la producción en la zona donde se analizó la validez del enfoque. La suma en valor absoluto de los indicadores SIRD, llamados Indice de Balance Nutricional, presentó correlación negativa y altamente significativa para los análisis foliares correspondientes a los meses de mayo.Diagnosis and Recommendation Integrated Systems (DRIS) norms were developed for the interpretation of N, P, K, Ca, Mg, Mn, Fe and B contents of coffee (Coffea arabica L.) leaves, obtained from a N-P-K factorial experiment at two different locations of the Colombian Coffee Zone. For diagnostic purposes of coffee nutrition this is the first time a DRIS norm is derived. The DRIS approach allows a betterinterpretation of Coffee's leaf mineral contents than tables of "normal values" since it shows the dynamics of change ofcomposition of the plant as result of fertlllzer treatments and also lists all nutrients in order of requirement by the plant, for.example, K and gt;P and gt;Ca and gt;B and gt;N and gt;Mn and gt;Fe for both localitles. This was not clearly sho~n by the table of "normal values". DRIS also showed that calcium is not balanced as yield in. creased as result of fertilizar applications thus suggesting calcium may be a limiting factor for further yield increases. DRIS interpretation of leaf analysis was very similar for all sampling dates but for may samplings a highly significant correlationbetween the sum of absolute ORIS valuesand yield was found. ORIS might be a very useful tool for the interpretation of coffee leaf analysis

Net photosynthesis and co2 compensation concentration in three coffee (coffea sp.) genotypes, bean and maize under three temperaturas.

The coffee (Coffea arabica L.) genotypes Colombia, Caturra, and Híbrido de Timor, and bean (Phaseolus vulgaris L.) and maize (Zea mays L.) plants were exposed to three temperatures (15°C, 25°C and 35°C), and net photosynthetic rates (PN) and CO2 compensation concentrations (CO2) were measured. PN in coffee leaves was similar for the three genotypes at 15 °C [5,0 . 5,3 µmol(CO2) m-2s-1] and 35 °C [4,9 . 5,5 µmol(CO2) m-2s-1], but lower at 25 °C [5,4 . 11,7 µmol(CO2) m-2s-1]. CO2 increased with temperature in coffee and bean, while in maize no effect was observed. PN and CO2 values documented in coffee genotypes were typical for C3 plants

Desarrollo de un sistema de información y transferencia para el servicio de la comunidad cafetera nacional

IP 2251-14-1277

EFFECTS OF DAYLENGTH AND SOIL HUMIDITY ON THE FLOWERING OF COFFEE COFFEA ARABICA L. IN COLOMBIA EFECTO DE LA DURACIÓN DEL DÍA Y LA HUMEDAD DEL SUELO SOBRE LA FLORACIÓN DEL CAFETO COFFEA ARABICA L. EN COLOMBIA

Coffee flowering data were analyzed in order to explore the effect of two environmental variables that have been considered relevant for this process. Pre-anthesis stage flowers were counted in coffee leaf-rust resistant crops at eight experimental stations (between 2°N and 11°N). Likewise, climatic data were taken to generate a humidity soil index, whereas day longitude data were taken from the Smithsonian Meteorological Tables. Flowering data were compared with a sunshine index to understand better the effect of light on flowering. This data (flowering, soil humidity index and day length) were expressed in a monthly scale and analyzed using linear regression and cross-correlation functions. The main results show that there is a significant correlation between short days and high flowerings, whereas soil humidity (dry months) are related to the phenomenon, but to a lesser extent.Con el objetivo de entender el efecto de las variables ambientales sobre el cultivo del café, se analizaron los datos de floración para explorar el efecto de dos variables que han sido reportadas como importantes en la floración de esta especie. Se contaron flores en etapa de pre-antesis en cafetales sembrados con variedades resistentes a roya en ocho estaciones experimentales entre 2°N y 11°N. A su vez, fueron tomados datos del clima para generar un índice de humedad del suelo, mientras que los datos de longitud del día se tomaron de las tablas meteorológicas del Smithsonian; para entender mejor el efecto de la luz sobre la floración, fueron comparados los datos de floración y un índice de brillo solar. Estos datos (floración, índice de humedad del suelo y longitud del día) se expresaron en escala mensual y se analizaron utilizando regresión lineal y funciones de correlación cruzada. Los resultados muestran que hay una correlación importante entre días cortos y altas floraciones, mientras que la humedad del suelo (meses secos) tienen una relación con el fenómeno, pero con menor correlación

Effects of daylength and soil humidity on the flowering of coffee coffea arabica l. in colombia.

Coffee flowering data were analyzed in order to explore the effect of two environmental variables that have been considered relevant for this process. Pre-anthesis stage flowers were counted in coffee leaf-rust resistant crops at eight experimental stations (between 2°N and 11°N). Likewise, climatic data were taken to generate a humidity soil index, whereas day longitude data were taken from the Smithsonian Meteorological Tables. Flowering data were compared with a sunshine index to understand better the effect of light on flowering. This data (flowering, soil humidity index and day length) were expressed in a monthly scale and analyzed using linear regression and cross-correlation functions. The main results show that there is a significant correlation between short days and high flowerings, whereas soil humidity (dry months) are related to the phenomenon, but to a lesser extent