Distribution of zinc pools as influenced by long-term application of fertilizers and manure in a Vertisol

Abstract

The present investigation was carried out a permanent site at the Research farm of the Department of Soil Science and Agricultural Chemistry, Jawaharlal Nehru Krishi Vishwa Vidyalaya Jabalpur. The study was aimed to find out the effect of continuous application of inorganic fertilizers and organic manure on the depth wise distribution of Zn fractions under soybean-wheat cropping sequence in a Vertisol at Jabalpur, Madhya Pradesh during 2016–17. The experiment consists of ten treatments i.e. T1 50% NPK, T2 100% NPK, T3 150% NPK, T4 100% NPK + Hand weeding, T5 100% NPK + Zn (ZnSO4), T6 100% NP, T7 100% N, T8 100% NPK+FYM, T9 100% NPK–S (Sulphur free) and T10 control with four replications in a randomized block design. Results revealed that the highest content of DTPA-Zn and its fractions (water soluble-Zn, exchangeable-Zn, complexed-Zn, organically bound-Zn, occluded-Zn and residual-Zn) were recorded in the treatment receiving 100%NPK + Zn, followed by 100% NPK +FYM; while the lowest content of DTPA-Zn and thier fractions were noted in treatment where no fertilizer and organic manure was applied since inception of experiment. The available Zn and various Zn fractions were found to be higher in 0–20 cm soil depth which decreased with increasing soil depth in all the treatments. Zinc content in various fractions varied in the order of water soluble