Effects of salinity and rate of irrigation on yield, fruit quality and mineral composition of 'Fino 49' lemon

Potential problems associated with saline irrigation waters can be compounded by irrigation practices. Methods for water application become of prime importance under saline conditions. The effect of irrigation water quantity and salinity on fruit yield, fruit quality and leaf mineral composition were studied in a field experiment with 6-year-old lemon trees, cv. Fino 49, on the Macrophylla, (Citrus Macrophylla Wester) rootstock during 1998-2000. Trees were irri.-ated with three different qualities of water, having an electrical conductivity 1, 2.5 and 4 dS/m, respectively. For each salinity treatment, trees were irrigated with two different quantities of water, 100 and 125% crop evapotranspiration. Lemon fruit yield significantly decreased with increasing salinity, due to a decrease in the number of fruits per tree. This reduction was caused by an increase in fruitlet drop off induced by salinity. A significant increase of lemon fruit yield was observed in the last year by increasing the quantity of water. Salinity and amount of water applied affected fruit quality. The percentage of fruit juice, with respect to the total fruit weight, was greater in fruits from the control than for those in the salinity treatments. The opposite effect was observed for peel and pulp contents. Titratable acidity (TA) and total soluble solids (TSS) decreased with salinity, although the ratio TSS:TA was similar in all treatments. Chloride and sodium concentrations in leaves were raised by salinity and amounts of water applied. Data on accumulation of other nutrients in relation to salinity, water application and season are also presented. (C) 2002 Elsevier Science B.V. All rights reserved.