Growers in Florida face unique challenges regarding maintaining proper citrus nutrition.Poor draining soils with low fertility, low C.E.C., and high rates of leaching are common in thisregion. In response to these challenges, interest has grown in products labeled as soil conditioners.Using a completely randomized experimental design, this greenhouse study tested the effects of 5different combinations of a traditional fertilizer (TF) and a new soil conditioner (SC) on lemon andorange seedling physiology. Eight-month-old 'Bearss' lemon and 'Valencia' sweet orange graftedon sour orange rootstocks were employed, and five repetitions were used for each treatment. Plantbiomass (dry weight), height, stem diameter, chlorophyll content, stomatal conductance andnutrient uptake were analyzed after 120 days of treatment. The results show that SC has a positiveimpact upon both chlorophyll levels and stomatal conductance values in both orange and lemonseedlings. However, based on dry weight growth data, we can only conclude that the SC waseffective for orange seedlings at 50% TF and 0.5% SC. Based on this short 120-day evaluation, theSC achieved positive growth promotion for orange (50% TF) but not for lemon seedlings.
Keywords: citrus physiology; fertilization; soil amendment.