Nutritional status and nutrient use efficiency in tree species of subtropical forest in southern Brazil

Leaf nutrient concentration and the nutrient use efficiency (NUE) were compared among five canopy tree species of a subtropical forest in southern Brazil. Healthy and fully expanded leaves were collected under similar conditions such as canopy position and light exposure. Leaves were dried and ground, the macronutrients (N - Nitrogen, P - Phosphorus, K - Potassium, Ca - Calcium, Mg - Magnesium, S - Sulphur) and micronutrients (Cu - Copper, Fe - Iron, Mn - Manganese; Zn - Zinc and B - Boron) were determined by argon-plasma, optical-emission spectrometry (ICP OES), N by Kjeldahl method, and B by azomethine-H way. The mean leaf concentration of nutrients was similar to other subtropical ecosystems but there was a high interspecific variation, indicating that the species use the nutrients differently from a common pool from the soil. The nutrient use efficiency (NUE) sequence was P> S> Mg> Ca> K> N for macronutrients while for micronutrients the sequence was Cu> B> Zn> Fe> Mn. The elements P, Mg and S had higher NUE in all species. These results suggest different strategies to acquire and use of these essential elements for tree species growing in the same soil type. The interspecific differences of NUE can contribute to explain the coexistence of these species in natural forest communities.