Mineral nutrition of taro (colocasia esculenta) with special reference to phosphorus

IT IS CALLED COCOYAM IN WEST AFRICA AND GABI OR ABA IN THE WEST INDIES. IT HAS BEEN USED IN EGYPT AS THE INITIAL CROP FOR RECLAIMING SALT-AFFECTED SANDY SOILS. IT CAN BE GROWN ON UPLAND SOILS OR IN LOWLAND WATERLOGGED SOILS, AND IT RESPONDS WELL TO FERTILIZATION, PARTICULARLY WITH NITROGEN AND PHOSPHORUS. THIS PAPER BRINGS TOGETHER SCATTERED REFERENCES TO ITS CULTIVATION. NITROGEN FERTILIZATION INCREASED CORM WEIGHTS OF BOTH LOWLAND AND UPLAND CROPS (DE LA PENA, 1967). PHOSPHOROUS APPLICATIONS APPARENTLY INCREASED THE SPECIFIC GRAVITY AND HASTENED THE MATURITY OF CORMS (EZUMAH, 1976). IN POTTED PLANTS, BOTH N AND P INCREASED CORM DRY MATTER, BUT IN THE ABSENCE OF P, THERE WAS NO RESPONSE TO N BEYOND THE 400 KG/HA APPLICATION. REGARDLESS OF P RATES, TARO ROOTS GROW LESS IN NON-FLOODED TREATMENTS THAN IN FLOODED TREATMENTS. IN HAWAII, FLOODED TARO RESPONDS MORE TO N THAN TO OTHER NUTRIENTS, WHILE NONFLOODED TARO RESPONDS MORE TO P THAN TO N (PLUCKNETT ET AL., 1970). FRESH WATER IS BETTER FOR GROWING FLOODED TARO, BECAUSE MOST TARO VARIETIES ARE SUSCEPTIBLE TO ROOT ROT IN WARM STAGNANT WATER. SOME DETAILED FINDINGS ON FERTILIZED TARO PRODUCTION IN HAWAII ARE DISCUSSED.