The objective of this study was to determine mixtures of regional organic residues that present aggregation to the root system and make a good development possible for Eucalyptus seedlings in block systems. Residues of coconut fiber (fine fibers - FCF, long fibers - FCL and mixed fibers - FCM), eucalyptus bark (CE) and sugarcane filter cake (T) were used, with ten mixtures obtained. The blocks for the expansion tests were made in a steel form (11.5 x 2.3 cm), and afterwards moistening and evaluating for the volume and height increment. There was not a difference in the volume increment among the mixtures, and mixture 3 presented a larger increment in height than in mixture 8, however, they didn't differ from those remaining, with those chosen for use in the production of eucalyptus seedlings: FCM (40%) + T (60%); CE (60%)+ FCM (40%); CE (40%) + T (60%) and CE (40%) + T (30%) + FCM (30%). The choice was made in consideration of the component's readiness, because it did not differ in the tests. The Eucalyptus urophylla seedlings were produced in 40x60x7cm trays, with 96 seedlings, sown directly in the blocks made with the selected mixtures pressed or not pressed. At 90 days the seedlings were evaluated for the diameter, height, shoot and root dry matter. In the expedition time, the substrata were evaluated as for the stability of the turf and the aggregation degree of the substrata to the seedlings roots. The nutritional analysis of the shoot seedlings was accomplished (N, P, K, Ca, Mg, Mn, Zn, Fe). All the substrata presented aggregation and good stability. Nutritional problems were not observed in the seedlings. For the production of Eucalyptus urophylla seedlings in blocks with pressed substrata the substratum CE (60%) + FCM (40%) is recommended, and without being pressed the mixtures: CE (60%) + FCM (40%); CE (40%) + T (60%) and CE (40%) + T (30%) + FCM (30%) were recommended.
Aggregation; Eucalyptus urophyll; Roots
