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Ten cooperating farmers in Northeast Thailand obtained a mean net yield of 1.8 tonnes/ha/yr of Nile tilapia (Oreochromis niloticus) in 200-m2 ponds manured at a rate of 200 kg dry matter (DM)/ha/day. Farmers were enthusiastic about the trial but fish production was most inefficient. A mean of 4.0 tonnes of fresh manure was collected and loaded into the 200-m2 pond over a 7-month period to yield only 20.7 kg of fish. Mean manure to fish conversion ratios were 195 and 34:1 on fresh and dry matter bases, respectively, with a dry matter conversion efficiency of manure to fish of less than 1%. Buffalo manure should not be recommended to farmers as a major pond fertilizer.

Juni 2002 is een belangrijke maand in dit biologisch traject: de start van het tweede deel van Bioveem en de opening van de nieuwe onderzoeksstal van Aver Heino.

Mejora genética participativa de la variedad criolla de frijol Sacapobres. Agricultores experimentadores de la Región Brunca de Costa Rica solicitaron en el año 1999, al Programa de Investigación y Transferencia de Tecnología Agropecuaria en frijol (PITTA Frijol), la mejora genética de la variedad criolla Sacapobres, una de las principales variedades criollas de la Región Brunca, que posee precocidad (60 días a cosecha, superando en más de diez días a la variedad mejorada más precoz) y alto potencial de rendimiento en grano (no había podido ser sustituida por las variedades mejoradas en sus campos de producción), pero de alta emisión de guías y acame. En el Centro Internacional de Agricultura Tropical (CIAT) y la Escuela Agrícola Panamericana Zamorano, se efectuaron hibridaciones con esta variedad criolla. La selección de los materiales segregantes se inició en los años 2000 y 2001, en Costa Rica y se basó en la metodología de fitomejoramiento participativo (FP). Los sitios de selección fueron fincas de agricultores y una estación experimental. El principal criterio empleado por los agricultores fue la arquitectura erecta (ausencia o poca emisión de guías y sin acame) para facilitar el tránsito por el terreno en las labores de deshierba y fumigación, seguido del tipo, tamaño y color de grano e incidencia de patógenos. Se seleccionaron, en el año 2005, dos líneas promisorias, que pasarán a la etapa de validación. Se describe la estrategia de selección en FP, la genealogía de los progenitores empleados y se concluye sobre el futuro mejoramiento de Sacapobres.

Naast enkele inspirerende inleidingen bestond het programma uit de presentatie van de 17 deelnemende biologische melkveehouders.

Accurate estimation of the size and spatial distribution of the yield gap has many practical applications, including relevance to precision agriculture and technology targeting. The objectives of this study were to illustrate a methodology to create a yield gap map and to discuss its potential uses to provide optimal crop management recommendations to the farmers. We used the HybridMaize crop simulation model to estimate potential yield for maize grown in the winter season in northwestern Bangladesh. This is a high yielding environment, where farmers achieve yields as high as 12 Mg/ha. The model predicted a mean potential yield of 12.87 Mg/ha. We used a RapidEye satellite image acquired around tasseling to identify the maize fields, calculate ground cover and its regression to actual yield from farmers’ fields. Next, the regression was applied to all the maize pixels in the image to calculate actual yield. In the last step, we created a yield gap map based on the difference between potential and actual yield. Yield gap maps will enable agronomists to identify production constraints on farmers’ fields with large yield gaps. Alternatively, by learning from the farmers with the highest actual yields and analyzing their data, it will be possible to generate region or field specific, optimized crop management recommendations.

Farming systems research/extension (FSR/E) embodies a systematic methodology beginning with problem identification and ending with dissemination of appropriate technology. Farming systems research (FSR) is a relatively recent approach dating back to the early 1970's (Collinson, 1972; Ruthenberg, 1971). Work initiated at ICTA in 1973 represents one of the first attempts to institutionalize FSR/E (Hildebrand, 1981). During the past 10 years, this methodology was more fully conceptualized and put into practice. Importation reductions were achieved for corn, beans, rice, and sorghum, with beans now an export crop. These results were achieved through application of FSR/E methodology with a focus on small-farm producers. Based on the farming systems methodology developed in Guatemala, the University of Florida initiated a FSR/E pilot program in 1981. The program is directed at technology generation for small farmers of north Florida and has emphasized improved grain and forage systems. On-farm reserach has proven critical in rapid problem identification and solution testing and is key to strengthening the farmer-extension-research connection.