Fractions of ferrous in calcareous Vertic Haplustepts as influenced by sixteen years of fertilization and Manuring in LTFE soils

The effect of integrated nutrient management (INM) on fractions of ferrous under groundnut-wheat cropping sequence of a Haplustepts soil was studies in a long-term field experiment initiated during kharif 1999 at Junagadh, Gujarat. Effect of varying dose of N, NP, NPK with FYM, Zn, S and Rhizobium on fractions of ferrous. The study was aimed to find out the effect of continuous application of inorganic fertilizers and organic manure on the distribution of Fe fractions. There was an increase in soil DTPA available Fe status of LTFE soils, while some important forms of Fe such as reducible Fe, total Fe and residual Fe was recorded decline. The conversion of exchangeable to DTPA-Fe was evident. In light of this, overall mean DTPA available Fe was recorded medium values (6.87 ppm) as compared to the critical values. Further the internal turnover of Fe along with other fertilizers could also help avoid the deficiencies of Fe even on a long run. The whole spectrum warranted a need to supply Fe nutrient through suitable sources to stabilize Fe status in the soil. The total form was a predominant component followed by DTPA available Fe. There were inter-conversions from DTPA available as well as total form to the reducible forms in a long run.