Respuesta del álamo euroamericano Populus x canadensis ‘Conti12’ a la fertilización nitrogenada en el Alto Valle de Río Negro, Argentina

The aim of this work was to evaluate the response of poplar to different doses of nitrogen fertilization after afforestation establishment. The experiment was carried on in a 3-years old hybrid poplar stand of clone Populus . canadensis ‘Conti12’ with a plantation density of 555 trees · hectare-1. A complete randomized block design was used, with 4 replications and 20 trees per plot. Four levels of fertilization were applied in October 2014, corresponding to 0, 90, 180 and 360 grams of urea (N-P-K: 46-0-0) per plant, equivalent to 0, 50, 100 and 200 kg urea · ha-1. Chlorophyll content was evaluated throughout the first 120 days and diameter at breast height (DBH; cm) and height (H; m) was evaluated for two years. Differences in absolute increment in DBH between fertilized and control trees were observed only after the first growing season. The response to nitrogen fertilization was greater in trees with lower DBH (