Characterization of tomato growth and fruit quality under foliar ammonium sprays

Abstract

This study was done to evaluate the effects of foliar application of ammonium sulfate on growth and fruit quality of tomato plants under hydroponic culture system. Over four months of tomato plant growth, plants were sprayed once per week with different concentrations of ammonium sulfate (0, 50, 100 and 200 mM), as well as with 50 mM every second day. Foliar application of ammonium sulfate led to reductions in many growth and quality parameters, and higher ammonium concentrations exerted greater reductions. Number of leaves, fresh weight of shoots, percentage of leaf dry weight and fruit yield were negatively associated with the treatment with ammonium sulfate. However, leaf nitrogen concentration, fruit diameter and fruit length increased significantly by the application of ammonium. Fruit quality factors were also affected by ammonium sulfate spray treatments. The maximum pH, titratable acidity and total soluble solids (TSS) were obtained from the lowest (50 mM) weekly application of ammonium sulfate. The results indicate that foliar application of ammonium in moderate concentrations could have beneficial effects on plant growth and quality of tomato fruit.