Seedlings growth and nutrient uptake responses of Citrus spp. (Citrus jambhiri and Citrus reshni) to foliar and soil nutrient application rates

Tree crop growth and nutrient uptake responses to applied nutrient types and rates are varied affecting their growth performances at the nursery and field stages. Experiments were conducted in 2019 in Abeokuta, Nigeria to evaluate the performances of two Citrus spp. for their responses to foliar and soil nutrient application rates applied a week after transplanting of seedlings. The 2×5 factorial experiment in a completely randomized design included two species of Citrus, C. jambhiri and C. reshni, and fertilizer rates applied at zero (control), foliar applied macro and micro nutrients at 1% v/v dilution rate, soil amendment with inorganic fertilizer NPK 15:15:15 at lower (62.5 kg ha^‑1) and higher rates (125 kg ha^‑1) and integrated application of both foliar and the lower NPK rates replicated three times. The results showed that ‘Cleopatra’ mandarin exhibited significantly higher growth responses in the plant height, stem girth, number of leaves, canopy spread and canopy area. The fertilizer responses showed no significantly difference in plant height, stem girth, number of leaves, canopy spread and canopy height. Significantly higher nutrient uptake of N, P, K and Mg was observed for ‘Rough’ lemon compared to ‘Cleopatra’ mandarin which nonetheless was higher in Fe compared to ‘Rough’ lemon. Likewise in the proximate content higher moisture content (MC), crude protein (CP), chlorophyll (TC) was observed for ‘Rough’ lemon but ‘Cleopatra’ mandarin was higher in fat content (FC), crude fibre (CF) but not different in ash content and carbohydrate (CHO). In summary, the advantage of easy absorption using foliar sprays did not translate into improved growth of citrus species.