Modification in growth, biomass and yield of radish under supplemental UV-B at different NPK levels

Growth, biomass, yield and quality characteristics of radish (Raphanus sativus L. var. Pusa Himani) were investigated under supplemental UV-B (sUV-B; 280–320 nm; +7.2 kJ m−2 d−1) radiation at varying levels of soil NPK. Combinations of NPK were recommended, 1.5 times NPK, 1.5 times N and 1.5 times K. sUV-B radiation negatively affected the growth and economic yield with more reductions at 1.5 times recommended NPK, N and K compared to recommended NPK. Total biomass remained unaffected in plants at recommended NPK under sUV-B radiation. At 1.5 times NPK and N more partitioning of biomass to shoot led to reduction in root shoot ratio and consequently yield under sUV-B. Nutrients in edible part declined maximally at 1.5 times recommended K under sUV-B. The study suggests that higher than recommended NPK makes radish plants more sensitive to sUV-B in terms of yield by allocating less photosynthates towards roots compared to shoots.