The impact of foliar nickel fertilization on urease activity in pecan trees

Abstract

The aim of the present work is to analyze the effect of different foliar products of nickel (Ni) on the nutrient concentration, chlorophyll content, and enzymatic activity of urease as the possible bioindicator of the levels of Ni in the leaves of pecan [Carya illinoinensis (Wangenh.) K. Koch]. The experiment consisted of the foliar application of Ni to pecan cv. Western Schley, using two commercial products: Nickel Plus®T1 and Speedfol™ PecanoT2, and a control T0 received no Ni treatment. The following variables were evaluated: the total chlorophyll concentration, the concentration of macro- and micronutrients including Ni, and the activity of urease. The results demonstrated that the pecan trees treated with Ni increased in the concentration of this element and that the product Nickel Plus® T1 increased by 41.24% with respect to control. The foliar application of Ni led to significant differences in the foliar concentrations of N, P, K, Ca, Mg, Fe, Mn, Cu, Zn, and Ni. Chlorophyll showed a significant reaction to the foliar application of Ni. The enzymatic activity of urease proved to be positively related to the foliar level of Ni, and thus could be considered a good physiological bioindicator of the nutritional state of foliar Ni in the leaflets of the pecan tree.