Abstract
Efficient use of nutrient and water through underground drip irrigation is one of the options to optimize sugarcane production with minimal ground water pollution. Experiments were conducted at the Japan International Research Center for Agricultural Sciences, Subtropical Research Station, Ishigaki, Okinawa, to (1) investigate the suitability of drip-tubing materials for fertigation, (2) find out the most suitable liquid poly feed fertilizer mixture and its application frequency, and (3) compare slow and rapid nutrient releasing granular fertilizers with liquid fertilizer mixtures in order to optimize sugarcane production. Stem cuttings and shoots of NiF 8 sugarcane variety were fertigated with the poly-feed 2, 3, 5, and 6 liquid fertilizer mixtures at different frequencies. Rapid (N-15 and N-16) and slow (424-70 and 424-140) nutrient releasing fertilizers were applied manually to sugarcane and irrigated through the drip system. Results showed that the growth of shoot-planted sugarcane in all treatment combinations was higher than that of stem-planted sugarcane. Vegetative growth of sugarcane was greatly promoted in irrigated, organic matter ameliorated soil compared to un-irrigated rapid nutrient releasing fertilizer mixtures. Among poly-feed fertilizers, the poly-feed 3 (15(N):30(P):15(K) + micro-elements) fertilizer mixture resulted in increasing height, diameter, and weight of stem of shoot-planted sugarcane, when compared to unirrigated organic matter amended soil by 44%, 10%, and 66% respectively. The increases of similar parameters in stem-planted sugarcane were 45%, 14%, and 38%. Moreover, fortnightly application of poly-feed fertilizers for stem and shoot planted sugarcane gave the highest growth performance while application of once in two months, resulted in the lowest. In addition, the highest growth performance in both shoot and stem-planted sugarcane was observed in the irrigated 424-70 slow nutrient releasing fertilizer mixture application. Super typhoon 120 was the most suitable tubing material for under ground drip systems in sugarcane cultivation. It is evident from results, that either fertigating of poly-feed 3 fertilizers fortnightly or slow nutrient releasing granular fertilizer (424-70) application linking with underground tubing material of drip line 2000 greatly promoted the sugarcane production; subsequently those practices could be extremely useful to minimize ground water pollution.
