Abstract

                                Five cycles of field experiments involving maize followed by sunflower were conducted during 1996-2001 in a clay loam soil at Agricultural College and Research Institute, Coimbatore. The results indicated that application of zinc sulphate @ 37.5 kg ha to first crop of maize followed by 12.5 kg ha¹ to all alternate sunflower crops increased the total yield of maize and sunflower together, showing beneficial resident effect of applied zine to previous crop, which received cumulatively 25% less zinc sulphate as compared to 12.5 kg ha-1 fo zinc sulphate applied to every crop in a sequence covering ten crops despite comparable yield were recorded among themselves. There was a build up of DTPA-Zn in the post harvest soil due to application of zinc sulphate, irrespective of levels, either to every crop or alternate crop over a period of time as against depletion of zinc observed in the treatments receiving only once and no zinc in the sequential experimentation.

Key words : Maize, sunflower cropping sequence, Zinc sulphate and DTPA-Zn.