Effects of algal colonization of Mount Pinatubo [Philippines] ash-soil mixture on the growth and yield of rice.
1994
Goss M.R.M. | Vite D. | Caberoy N. | Mendoza J. | Guevarra H.T.
Conspicuous growth of algae was noted on Mt. Pinatubo ash-soil after 20 days flooding. Soil sterilization suppressed the algal population; however, algal types remained the same as the unsterilized soil. Incubation of ash-soil on agarized defined inorganic media significantly increased the types and number of algae over the non-sterilized ash-soil. Field survey conducted on rice farmers in Pampanga [Philippines] regarding grain yield before and after Mt. Pinatubo eruption has divided the province into three classes: (1.) increased grain yield, (2.) unchanged yield, and (3.) loss of grain yield depending on the magnitude of ash fall. Grain yield increase in ash-soil mixture is attributed to high phosphorus content of the ash fall and early filling up of the grain. Loss in grain yield in areas heavily affected by the ash fall was due to the fine texture of the ash that resulted in poorly aerated soil under water stress. However, pot experiments, using different ash-soil mixture showed significantly higher grain yield of rice in higher ash (50-70 percent) than in lower ash content (25 percent). The difference in ash-soil texture accounted for the variation in plant response.
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