MSc

An investigation was carried out to determine the fertilizer requirements of ginger under varying shade intensities at the College of Agriculture, Vellayani during the year 1991-92. The experiment using ginger cv. Rio-de-Janeiro was laid out in strip plot design with four shade levels (S0, S1, S2, S3 ) and four fertilizer levels (F1,F2, F3 and F4) and was replicated five times. The shade levels were zero (open), 25, 50 and 75 per cent and the fertilizer levels were 75, 100,125 and 150 per cent of the recommended dose (75 : 50 : 50 N, P2o5 and K2o kg ha-1) as per the package of practices recommendations of KAU.
Under open conditions, plant height was found to be the lowest. Leaf number, leaf area index, chlorophyll content, crop growth rate, dry matter production, bulking rate and green ginger yield were found to be lower under open condition when compared to 25 and 50 per cent shade levels. However dry ginger yield under open condition was found to be comparable with that under 50 per cent shade and this might have resulted from high net assimilation rate and better partitioning under open condition as indicated by high utilization index and harvest index. Fertilizer treatments showed a positive influence on vegetative growth, chlorophyll content, rhizome yield and NPK uptake. Under open conditions, significant increase in dry ginger yield was obtained only upto F3 and maximum profit was also obtained for F3. Quality of the produce was found to be unaffected by fertilizer treatments.
Growth and yield of ginger were found to be the highest under 25 per cent shade. Response to fertilizer treatments in terms of growth characters and yield were found to be the highest under this shade level. Significant increase in green and dry ginger yield was obtained with each increment in fertilizer dose upto the highest level, F4. Quality of ginger was also superior under low shade and was unaffected by fertilizer treatments.
Under 50 per cent shade vegetative growth and dry ginger yield were higher than that under open conditions but lower than that under 25 per cent shade. Though the leaf area index and dry matter production were comparable with that under 25 per cent shade, poor partitioning as indicated by lower utilization index and harvest index might have contributed to the lower yield. Under this shade level, as fertilizer dose increased from F1 to F4, significant increase in yield was obtained. But the increment was only 9.5 per cent as against 20.1 per cent obtained under 25 per cent shade.
Under 75 per cent shade vegetative growth and rhizome yield were found to be highly reduced compared to open, 25 and 50 per cent shade. Response to fertilizer treatments was also poor. There was no significant increase in yield with application of fertilizers above F2 level.
The study clearly indicates the necessity of increasing the fertilizer dose to 150 percentage of the recommended dose when ginger is grown under 25 and 50 per cent shade.