The objective of this research was to evaluate the NPK fertilizer effect on 'Valencia' sweet orange nursery tree (Citrus sinensis) development, budded on Rangpur lime rootstocks (C. limonia) in a protected environment using containers with Pinus bark, vermiculite and perlite substrates. The experiment consisted of a complete (1/5) 5³ factorial randomized block design. Treatments comprised five concentrations in g per plant of N: 1.25; 6.25; 11.25; 16.25; 21.25; five concnetrations of K: 0.42; 3.75; 6.22; 9.34; 12.45; and five concentration of P: 0.19; 0.89; 1.59; 2.29; 2.99. Nitrogen and K were applieded weekly, and 37.5% of the total fertilization was applied to rootstocks. All P was supplied at planting. Leaf, root, stem, shoot and total dry matter production, shoot/root ratio, leaf area, plant height, root system volume; leaf area dry matter ratio stem diameter were evaluated. Response functions were adjusted and nutrient rates for maximum yield are presented. Results showed that fertilizer level that lead to the best 'Valencia' sweet orange on Rangpur lime nursery tree response was (g per plant): N, 9.85; P, 2.86; K, 7.99.
Citrus sinensis; Citrus limonia; propagation; response function; fertilizer