Effect of Levels and Frequency of Zinc Sulphate Application on its Content and Uptake by Maize and Sunflower in their Sequential Cropping System

Field experiments involving maize var. CO. 1 in rabi season followed by sunflower var. CO. 2 in kharif season in a sequence were carried out to study the influence of levels and frequency of zinc sulphate application on zinc removal pattern during the year 1999–2000 and 2001-2002. The pooled analysis of experiment results revealed a distinct trend of zinc concentration and total uptake by maize and sunflower crops. As regards maize, application of zinc sulphate @ 37.5 kg ha−1 to first crop followed by 12.5 kg ha−1 to all subsequent crops in a sequence recorded the highest zinc content in grain (78 mg kg−1) and straw (75 mg kg−1) and application of zinc sulphate once at higher level (50 kg ha−1) for first crop alone (Maize) resulted in the highest total up take of zinc by grain and straw together (1289 g ha−1) and these were comparable among themselves. In respect of sunflower, application of zinc sulphate @ 12.5 kg ha−1 to every crop recorded the highest zinc content in seed (81 mg kg−1) and in stover (67 mg kg−1) and the highest zinc uptake of 431 g ha−1.