Progress 09/15/06 to 09/14/08
Outputs
OUTPUTS: The capacity of five bean cultivars to secrete citric acid under toxic levels of aluminum in solution was evaluated. The presence of citrate and oxalate was detected after 48 hours of exposure of bean seedlings to concentrations of 25 and 50 micro molar solutions of aluminum. An increase in citrate concentration was observed as the aluminum concentration increased. The tolerance of Morales bean variety to acid conditions was evaluated under field conditions. The selected soil was Corozal clay, a very acid Ultisol. Four liming rates were evaluated (0, 2.5, 5.0, and 10 t/ha). Soil pH was evaluated at 0-20 and 20-40 cm depths. Cation exchange capacity, exchangeable bases and exchangeable aluminum content of the soil were also evaluated. Data was collected on fresh bean yield and dry bean yield. The variety showed some degree of tolerance to acid soil conditions, but a positive response to lime applications was observed. Four methods to estimate lime requirement of acid soils were also evaluated. The methods included in the study were SMP buffer, Adams Evans buffer, Sikora buffer, incubation method and an estimate of lime requirement based on the exchangeable aluminum content of the soil. The results were presented at the Puerto Rican Society of Agricultural Sciences Annual Meeting, the Caribbean Food Crops Society Meeting and the American Society of Agronomy Meeting. The need for liming acid soils to optimize bean production has been notified to farmers through extension service personnel. The tolerance of Morales bean variety to acid soil conditions will help small farmers from the mountain area of Puerto Rico or regions in the Caribbean where acid soil conditions prevail and liming material is not always available or is to expensive. The use of the Sikora buffer to estimate lime requirement of acid soils will be recommended to farmers with the support of the Puerto Rico Department of Agriculture. This buffer method is rapid, reliable and more environmentally friendly than other buffer methods. A leaflet on soil acidity, aluminum toxicity and crop tolerance will be prepared in coordination with the Agricultural Extension Service to be distributed to farmers. PARTICIPANTS: The project had the collaboration of Dr. James S. Beaver, Dr. Felix Roman and Prof. Agenol Gonzalez. Dr. James Beaver is a plant breeder working with beans at the Agronomy and Soils Department, UPR Mayaguez. He contributed with the selection of bean cultivars and field evaluation and statistical analyses and Dr. Felix Roman conducts research in environmental chemistry at the Chemistry Department, UPR, Mayaguez. He was in charge of the anion chromatography analysis of organic acids secrete by bean cultivars. Prof. Gonzalez provided supervision and maintenance to field experiments at Corozal Agricultural Experiment Station. Dr. Munoz was the project leader and coordinator of all research activities. Also, was in charge of the supervision of the graduate students and all chemical analyses and laboratory work. Also, three graduate students, Sandra Ortega, Pedro Labayen and Emmanuel Feliciano worked in the research project. Sandra Ortega worked in the study of organic acid exudation and gained experience in the use of Anion Exchange Chromatography techniques. Pedro Labayen conducted his master thesis study evaluating the tolerance of bean cultivars to acid soil conditions and aluminum toxicity under field conditions. He had the opportunity to learn about acid soil management, liming methodology of acid soils, and gained experience in the use of atomic absorption spectroscopy, colorimetric techniques and nutrient availability tests. Emmanuel Feliciano evaluated different methodologies to estimate lime requirements of acid soils and gained excellent experience in wet chemistry analysis, atomic absorption spectroscopy, and management of acid soils. We established contacts with bean farmers and agronomists from the Puerto Rico Department of Agriculture and provide them with information about the benefits of liming acid soils and the need to select cultivars adaptable to acid soil conditions. TARGET AUDIENCES: Our target audiences were small farmers that produce beans for the fresh market and agronomists from the Puerto Rico Department of Agriculture from the Extension Service. These personnel were contacted through talks and oral presentations at forums like the annual meetings of the Puerto Rican Society of Agricultural Sciences and the Caribbean Food Crops Society. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Knowledge on the tolerance of bean varieties to acid soil conditions and aluminum toxicity will be very useful to provide farmers with a better genetic material for acid soil conditions on their farms. These bean varieties or cultivars can also be used as a genetic pool for future bean breeding initiatives. The fact that Morales bean variety showed some degree of tolerance to acid soil conditions and aluminum toxicity makes it more suitable alternative for acid soils in the mountain region where liming applications are very costly to farmers since mechanization of such practice is almost impossible due to the hilly topography. The evaluation of buffer methodology to estimate lime requirement of acid soils will provide alternatives for the Agrological Laboratory of the Puerto Rico Department of Agriculture for faster evaluation of lime requirements. The Sikora buffer proved to be as good method as any other buffer solutions and it has the advantage of being more environmentally friendly.
Publications
- Labayen P. E., M. A. Munoz, J. S. Beaver and F. Roman. 2006. Evaluacion de lineas de habichuelas (Phaseolus vulgaris L.) en un suelo Corozal bajo condiciones de acidez y toxicidad de aluminio. Sociedad Puertorriquena de Ciencias Agricolas, Guayanilla, Puerto Rico, 10 de noviembre de 2006.
- Labayen P. E. 2007. Evaluacion de lineas de habichuela (Phaseolus vulgaris L.) en un suelo de Corozal bajo condiciones de acidez y toxicidad de aluminio. Master's Thesis, University of Puerto Rico, Mayaguez.
- Feliciano E., M. A. Munoz, J. M. O'Hallorans and V. Snyder. 2007. Evaluacion de metodologia para determinar el requisito de encalado de suelos acidos. Sociedad Puertorriquena de Ciencias Agricolas (SOPCA), Catano, Puerto Rico.
- Feliciano E., M. A. Munoz, J. M. O'Hallorans and V. Snyder. 2008. Searching for the best methodology to Determine Lime Requirement of Selected Puerto Rican Soils. American Society of Agronomy Abstracts, Houston Texas, October 5-9, 2008.
- Feliciano, E., M. A. Munoz, J. M. O'Hallorans y V. Snyder. 2008. Uso de soluciones amortiguadoras para recomendaciones de encalado. Sociedad Puertorriquena de Ciencias Agricolas (SOPCA), Puerto Rico, Aguadilla, Puerto Rico, 20-21 de noviembre de 2008.
- Munoz, M. A., A. Gonzalez, J. S. Beaver, E. Feliciano and S. Perez Castro. 2008. Response of Morales bean variety (Phaseolus vulgaris) to liming applications on Corozal soil. Sociedad Puertorriquena de Ciencias Agricolas (SOPCA), Puerto Rico, Aguadilla, Puerto Rico, 20-21 de noviembre de 2008.
- Munoz M.A., J. S. Beaver, F.R. Roman and S. Ortega-Achurry. 2006. Citrate exudation by bean cultivars, a potential mechanism to overcome Al3+ toxicity. Caribbean Food Crops Society Meeting, San Juan Puerto Rico.
|