Fertilização mineral e orgânica em sistema agroflorestal

Abstract

Basic information on the proper utilization of fertilizers in relation to the crops’ nutritional requirements, especially in relation to demanding clones or their classes, are of paramount importance. The objective of this study is to evaluate the initial growth of eucalypt under different combinations of mineral and organic fertilizer doses in a silvopastoral system. Additionally, the availability of nutrients in the soil and the presence of weeds in Eucalyptus urograndis hybrid clones is analyzed. The experiment was implemented in Mineiros-Goiás in a delimitation of 20 units in a randomized block design (RBD): five treatments and four replicates. The evaluated clone was the hybrid Eucalyptus urophylla x Eucalyptus grandis. Five mineral and organic fertilizer combinations were tested: NPK (140 g plant-1) and SFS (105 g m-1) with three top-dressing fertilizations; NPK (140 g plant-1) and SFS (105 g m-1) with a single top-dressing fertilization; turkey manure (4090 g m-1) with three top-dressing fertilizations; turkey manure (2767 g m-1) with three top-dressing fertilizations; and turkey manure (1834 g m-1) and SFS (64 g m-1) with three top-dressing fertilizations. The DBH (diameter at breast heigHt), the average total plant heigHt and total volume were evaluated at 7, 11 and 24 months of growth. Weeds and soil fertility were evaluated at 12 months. The analysis of variance was performed with the F-test at 5 %, grouping test (Scott Knott) and linear correlation. Significant difference was observed between the treatments in response to the fertilization and availability of nutrients in the soil for the variables DBH and Vt. The treatments adopted did not present differences in relation to weed growth. In conclusion, the application of fertilizers interferes with the initial growth of Eucalyptus urophylla x Eucalyptus grandis clones in SAF, especially when the source is organic.