Kakawate ( Gliricidia sepium , Leguminosae ) as a soil amendment and biological control of soil-borne pathogens: the Philippines experience.

摘要

A documentation study was conducted on different plant materials utilized as alternatives of chemical fertilizers and pesticides in selected areas in Southern Luzon, Philippines. In all farms visited, results showed that ingenious, successful farmers utilized kakawate (Gliricidia sepium) on their rice farming. These farmers make use of the kakawate leaves in various ways: incorporated into the soil during land preparation, spread over as mulch and applied as spray on standing crops. The latter was a concoction of fermented leaves (popularly known for local farmers as "Kakawate Plus") sprayed on the rice crop at maximum tillering to reproductive stages. Other farmers prepared kakawate leaf extracts in combination with lesser-known plant resources (Andrographis paniculata, Derris trifoliata and Tinospora rumphii). This multi-purpose tree is popularly known to many farmers because of its high mineral composition that provides nutrients to crops, and chemical compounds that help control the insects and decrease population of soil-borne pathogens. In a separate study a long-term field experiment was conducted on a low-fertility clay soil (Aquandic Epiaqualf) at International Rice Research Institute-University of the Philippines Los Banos Experiment Station, Laguna, Philippines. Results of this study confirmed the efficiency of kakawate documented from farmers' experiences. After 9 rice croppings kakawate significantly improved rice grain yield providing healthy plants comparable to those plants with chemical fertilizers, and supporting the activities of beneficial soil organisms. General findings indicative of kakawate's pesticidal activity is the capability to boost the resistance of the rice crop to root infection, insect and disease infestation. The effectiveness of kakawate as plant nutrient source and bio-control of soil-borne pathogens can be an option for the future, as it guarantees yields, reduces costs, environmentally friendly and contributes to the sustainability of agriculture.