Influence of Iron Nutrition on Soil Properties, Uptake and Yield of Soybean Grown on Iron Deficient Inceptisol

Iron (Fe) is an essential micronutrient for optimum growth and yield of crop. In calcareous soils availability of Fe is low, to correct Fe deficient soil application of Chelated Fe-EDTA is often recommended to avoid the possible nutritional disorder due to antagonistic effect of Fe with other cationic micronutrients. The present study was initiated with an objective to evaluate response of soybean crop to soil and foliar application of iron. The experiment was carried out at Agricultural Research Station, Kasbe Digraj, Dist: Sangli (MS) during kharif 2018-19. The experimental soil was alkaline, calcareous, clay in texture, low in available nitrogen, phosphorus, very high in available potassium and deficient in iron. The experiment was laid out in randomized block design with eight treatments and three replications. The treatments comprised of common application of NPK fertilizers in conjunction with 10 t FYM ha-1, soil application of FeSO4 @ 10 and 20 kg ha-1 with and without 0.2 per cent spray of chelated Fe. The results revealed that the soil pH and electrical conductivity did not differ due to different treatments however, the organic carbon content was found to be slightly improved over control. The free calcium carbonate percentage in soil also found to be statistically non-significant although it revealed slight decline from the initial value due to different iron nutrition treatments. General recommended dose of fertilizers +Soil application of FeSO4 @ 20 kg ha-1 + two foliar sprays of chelated Fe @ 0.2 per cent at 30 and 50 DAS (T8) recorded significantly higher available N, P and DTPA Fe over control treatment whereas, available K, DTPA Zn, Mn and Cu were found to be statistically non-significant due to different treatment of iron nutrition along with NPK fertilizers and organic manure. Significantly highest total uptake of N, P, K, Fe, Mn, Cu and Zn by soybean was exhibited in T8 which was either equivalent or statistically at par to GRDF + soil application of FeSO4 @ 10 kg ha-1 + two foliar sprays of chelated Fe @ 0.2% at 30 and 50 DAS (T7). In general, all the treatments of iron nutrition were statistically at par in context of soil nutrient and nutrient uptake by soybean crop. Significantly higher grain yield (2493 kg ha-1 ), straw yield (3779 kg ha-1 ) of soybean was recorded by T8 which was closely followed by T7. All the treatments of iron nutrition irrespective of method of application recorded statistically at par grain yield of soybean nonetheless, soil application of FeSO4 was found to be beneficial in correcting the initial deficient iron and zinc status in the soil. In a nutshell, it can be concluded that soil application of FeSO4 @ 10 or 20 kg ha-1 is adequate for obtaining optimum soybean yield and sustaining soil fertility in an iron deficient, slightly calcareous Inceptisol soil.