Deficiência de macronutrientes em mudas de Sangra d’Agua (Croton urucurana, Baill.)

This study describes the effect of nitrogen (N), phosphorous (P), potassium (K), calcium (Ca), magnesium (Mg) and sulfur (S) deficiencies in seedlings of Croton urucurana, a pioneer species that tolerates flooding and is important for reforestation in semi-deciduous forests of Brazil. Studies of macronutrient deficiencies are important because Brazilian soils are more likely to be deficient in macronutrients than micronutrients. The study found that the omission of nutrients resulted in morphological alterations, with omission of N, Ca, and Mg affecting height, diameter, number of leaves, and number of branches. The authors reported visual symptoms of nutrient deficiency earlier in plants with N, K, Ca, and Mg omissions, followed by those subjected to P and S omissions. Visual symptoms included yellowing of leaves, reduced branching, and early senescence of leaves. Omission of nutrients did not affect dry matter yield. In sum, N, Ca, and Mg omission affected the development of the species most negatively.