Effects of zinc fungicides and different zinc fertilizer application methods on soluble and total zinc in potato plant shoots

The experiment was carried out to evaluate the effects of fungicides [with or without zinc (Zn)] and different Zn fertilizer application methods (no f ertilizer; soil application; shoot application; soil plus shoot application ) on the soluble and total Zn in the dry matter of potato shoots. Zinc fert ilizer was applied to the shoots at 20 and 45 days after plant emergence (D AE), immediately before plant sampling. At 25 DAE, Zn fungicide increased s oluble and total Zn in the fourth leaf. The same occurred, at 45 DAE, with the Zn fertilizer applied to the shoots. It were not observed significant i ncreases on both soluble and total Zn contents in the fourth leaf of plants that received soil Zn fertilization. Even in the leaves with 262 mg Zn kg( -1), there was no phytotoxicity symptoms. The total Zn concentration at 20 DAE was the best index correlated to potato tuber yield reaching 50.9 mg Zn kg(-1) in the fourth leaf of plants at the highest marketable tuber yield treatment. Plant nutrient element contents [phosphorus (P), calcium (Ca), m agnesium (Mg), copper(Cu), iron (Fe), and manganese (Mn)] were not affected by the treatments.