Zinc dynamics in an Alfisol as influenced by levels of farm yard manure

Abstract

Field experiments were conducted on sandy loam soil at Shimoga, Karnataka, India to study the influence of FYM application on dynamics of zinc in an Alfisol under fingermillet (Eleusine coracana L.) crop. Three levels of FYM viz., 7.5, 15.0 and 22.5 t/ha with and without recommended dose of fertilizer (RDF) were evaluated for the purpose. Changes in available (DTPA extractable) and different fractions of Zn in soil were monitored. Application of FYM at all levels, with or without fertilizers, caused significant (p<0.05) increase in DTPA-Zn, the effect being more pronounced at higher levels. Maximum DTPA- zinc (0.97 mg/kg) in soil was observed in the treatment RDF+FYM@ 22.5 t/ha. Increase in level of FYM application increased the water soluble, sorbed, easily reducible manganese bound, carbonate bound and organic bound fractions of Zn significantly (p<0.05), but decreased residual fractions in soil compared to that of RDF and absolute control treatments. All the fractions except residual one had positive and significant correlation with each other indicating the existence of a dynamic equilibrium among them. DTPA-Zn was positively and significantly (p<0.01) correlated with soil OC, WS, SORB, ERMn, CA, OM and Fe and Alox fractions (r= 0.683,0.603,0.683,0.702,0.777,0.678 and 0.476 respectively) in soil. The treatment receiving RDF+FYM @ 22.5 t/ha excelled over others with respect to grain and straw yield (3.028 t/ha and 1.890 t/ha respectively) of fingermillet. Thus, keeping in view the availability of Zn in soil and yield of fingermillet, FYM @22.5 t/ha supplemented with RDF was found to be the superior one.