The effect of nitrogen nutrition on growth, chemical composition and response of cucumbers (Cucumis sativusL.) to nitrogen forms in solution culture

Abstract

SummaryCucumber plants were grown under greenhouse conditions in a modified Hoagland’s solution to determine the effect of forms and combinations of nitrogen on growth and chemical composition, and the response of cultivars to N forms. Nitrate significantly increased dry weights of fruit, leaves and roots whereas ammonium decreased them. The N content of fruit, leaves, stems and roots; P in fruit, leaves and stems significantly increased when 50% or more of the N source was NH4, but NO3 decreased the N and P content in all parts of plant. With 100% NO3, there was an increase in the K and Mg content of the fruit; and a large increase in Ca levels in fruit, leaves, stems and roots. Fifty per cent or more of the N as urea significantly increased the N content in leaves and roots, P in all tissues, K in fruit and Mg in fruit and leaves. Ammonium as an N form decreased the K, Ca and Mg content of all tissues. Ammonium toxicity and necrotic effects of urea were observed when they represented more than 50% of th...