Department of Soil Science and Agricultural Chemistry, Tamil Nadu Agricultural University, Coimbatore-641 003, India.
Based on the classification of NIIs in turmeric growing areas 17 per cent were severely limited by mineral nutrition and about 32 per cent of turmeric growing areas were identified as having possible imbalances. Among the manurial treatments DRIS indices of Zn and Fe became more positive with M2 and M3, whereas M3 showed still more higher positive indices of Zn and Fe. DRIS indices showed that the soil application of Zn either with direct source or through enriched source with or without Fe in the FYM + Zn solubilizer treatment, Zn is no longer the most required nutrient. After 120 and 150 DAS, the data for the highest yielding treatments in this experiment, namely, M3among manurial treatments and F5 and F9 among the micronutrient treatments after 120 DAS, showed that the balance between Zn, Cu, Fe and Mn was most favourable in all treatments. The DRIS NII value of M1 (3099) was above the threshold value causing severe imbalances, whereas M2 (2873) and M3 (2799) were found to be under the balanced category of NII. In turmeric leaves, the treatments that received Zn either alone or in combination with Fe as soil application recorded lower Nil values (2117 to 2707) and were categorised under balanced range, whereas F6 (4290) and F7 (4192) the foliar spray treatments recorded higher NII value along with the control (3445) exhibiting severe imbalances among the nutrients in the leaves of turmeric crop. Among the different stages, St2(120 DAS) proved to be the correct stage for leaf nutrient analysis as the lowest Nil was associated at this stage. The correlation coefficient between yield and Zn indices were significant (r2= 0.92**) as compared to the Zn content in the leaf (r2= 0.79**) which clearly indicate the nutrient index of DRIS approach was more closely related to differences in yield.
