Evaluation of micronutrient status of sandy clay loam as influenced by sulphur fertilization on blackgram
Secondary nutrient deficiency especially sulphur (S) in blackgram has imparted poor grain setting percentage and yield as well. Interest on S availability in soils has increased due to acute shortage production of quality blackgram. Therefore, an attempt was made to assess the three SO4-2- S sources (Gypsum, Ammonium sulphate and Potassium sulphate) and two S levels (10 and 20 kg S ha-1) under irrigated condition. This experimental trial was replicated three times along with randomized block design at farmer field of Thenamallur village, T. Kallikudi block, Madurai district. S treatments were also evaluated by two methods of fertilizer amendment such as, soil application (as basal dose) and foliar spray (0.5 % K2SO4) on 30th and 45th days after sowing and its combinations. Soil analysis is good method to assess the S nutritional status of soil under tropical areas. The results revealed that the S and micronutrient content was low in single soil application or foliar spray and irrespective of source and level. Foliar spray treatment plants recovered limited S concentration. We could found that the better higher S concentration among the combination treatments. Soil application of K2SO4 @ 20 kg ha-1 + foliar spray was increased the soil available S and DTPA - extractable Micronutrient (Zn, Fe, Mn and Cu) status. Our study explains that the treatment combinations had synergistic effect and it may be concluded that the combinations (soil + foliar spray) are increased soil available S and micronutrient status. Further, future studies are required to confirm the results of S fertilizers in alkaline soil.