Estudo do crescimento e estado nutricional de carapa guianensis em sistemas de plantios em área degradada na Amazônia Central

Abstract

We analyzed the growth in total height (ht), diameter at 1,30m (DAP) and nutritional status of leaves of trees (Carapa guianensis) at 46 months old planted 5 m x 5 m spacing in areas degraded by agriculture and livestock, at a site in the Community Rio Canoas, km 139, BR174, in the city of Presidente Figueiredo-AM. The experimental design used was DIC (completely randomized design), arranged in eight treatments with four replicates of five plants each. The treatments received different doses of chemical fertilizer and chicken manure at the time of planting, and one treatment received no fertilizer (control). Were three measurements of height and diameter, on the date of planting, at 38 months and at 46 months of planting, and two collections of leaves and soil (38 and 46 months). 10 leaves were collected from five trees per plot with dominant height. The contents of N, P, K, Ca and Mg and micronutrients Mn, Fe, Cu and Zn. For soil analysis, two samples were taken in each treatment, a total of two composite samples, each resulting three single samples and determined the levels of macro and micronutrients. There were no significant differences (F = 1,65, p> 0,05) in the mean total height between the different treatments, however, the T7 treatment fertilized with NPK (4-14-18) had a mean total height of 6,8m. The DAP had siginificant difference between treatments (F = 2,12, p <0,05) whereas the T2, fertilized with NPK (10-10-10), had a higher mean diameter (8,5 cm) to 46 months. The highest rate of survival (95%) was observed in T1, T2 and T4 and differ significantly (p <0,05) treatment T6 (75%). With regard to nutrition leaves, there was significant difference (p <0,05) between treatments in Ca, K, P, Fe, Mn and Cu. The average levels of other nutrients Mg, N and Zn were not statistically significant (p> 0,05). In overview, the different forms of fertilization showed different effects on the development and content of nutrients in the soil of each treatment. It can be concluded that the species C. guianensis has excellent potential for planting in degraded areas in the Amazon region. In general, the effects are visible provided by chemical fertilization treatments (T1, T2, T3, T5, T7, T8) and chicken manure (T4) with regard to foliar nutrients, due to higher levels of macro and micronutrients, growth rate and survival when compared with the control treatment (T6) that was not fertilized. These results support the hypothesis that the adoption of best practices in soil management, through the use of fertilizers and brokers soil acidity, is the best alternative for restoration of degraded areas using the species studied.