Effect of sulfur deficiency and excess on yield and sulfur accumulation in tomato plants

Tomato (Lycopersicon esculentum Mill. var. hybrid 6C‐204) plants were grown for 95 days after germination until each one bore 6 ripe clusters in a greenhouse using nutrient solutions with nine added sulfate levels ranging from 0 to 105 me/1. Sulfur‐deficiency symptoms and characteristics of plants growing under hign SO4‐S levels were observed and described. Fruit yields were negatively affected by both S‐deficiency and high SO4‐S concentrations. Top growth was affected more than root growth by changes in the amount of SO4‐S supplied. The critical SO4‐S concentration in the growth media ranged from 2 a 22.5 me/1. Leaf sulfate‐S increased gradually in leaves and roots as SO4‐S supply in the nutrient solution increased while organic‐S remained relatively constant. Leaf sulfate‐S critical value was growth stage dependent. Maximum yields at flowering were associated with leaf concentrations of 0.48–1.2% SO4‐S and 0.25–0.35% organic‐S.