Carbohydrate-based urban soil amendments to improve urban tree establishment

Introduction: A factor limiting the development of tree vegetation in urban environments is the condition of the soil. Objective: To evaluate the effect of the application of carbohydrates (sucrose and glucose) to the soil regarding the growth and vitality of jacaranda trees (Jacaranda mimosifolia D. Don) planted in urban areas. Materials and methods: Eight carbohydrate treatments and one control (water) were applied. Increase in height and diameter, foliage color, chlorophyll fluorescence, dry root matter, root starch, respiration and soil moisture were evaluated. An analysis of variance and a comparison of means was performed (Tukey, P < 0.05); when the normal distribution of the data was not proved, nonparametric methods were used (Kruskal-Wallis and Wilcoxon rank-sum test). Results and discussion: The increase in height and diameter, the green color of the foliage and the fluorescence of the chlorophyll showed no significant differences (P > 0.05). Dry root weight and soil respiration were significantly different (P < 0.05) with higher response in the highest carbohydrate treatment (80 g·L-1 glucose with 80 g·L-1 sucrose). There was no effect on the characteristics of the aerial part, possibly due to the short evaluation time (about one year). Conclusion: The amendment of glucose and sucrose to the soil in urban trees stimulated the root growth of J. mimosifolia.