DESENVOLVIMENTO DE PLANTAÇÕES DE Bertholletia excelsa Bonpl. EM ÁREA DEGRADADA SOB DIFERENTES TRATAMENTOS DE PREPARO E ADUBAÇÃO.

Abstract

The objective of this work was to evaluate the survival and development of Brazil nut tree (Bertholletia excelsa Bonpl.) seedlings planted in degraded areas with different soil preparation and fertilization. For this purpose, we carried out an experimental planting of B. excelsa in an abandoned pasture area of Fazenda Santa Rita da União, Canaã dos Carajás / PA, a region bordering the mosaic of conservation units in Carajás. We implemented four experimental treatments in 1-hectare plots with the following preparation characteristics: standard T00- (hydrogel, chemical fertilizer); Wet organic T01- (hydrogel, organic fertilizer); T02- dry organic (without hydrogel, organic fertilizer), and T03- dry (without hydrogel, chemical fertilizer). The spacing of B. excelsa seedlings was 12 x 12 m. The seedlings were over 2 years old, 60.9 cm in average height, 4.6 mm in average diameter, and 9 leaves on average. The total number of seedlings was 337. During two years of monitoring, we collected dendrometric data (total height, Diameter at Ground Height - DAS) and leaf count in all seedlings and noted episodes of disturbance, regrowth, and/or death of seedlings for quarterly periods. Among the main results we highlight: 1) the soils of the four planting treatments are similar, with a sandy loam texture and high levels of fertility; 2) low seedling mortality rates in all treatments, providing a total survival rate of 82.8%, however, T01 showed a significantly lower survival rate than the other three treatments in the last monitored period (24 months); 3) concentration of herbivory events in the months of July and October in the two years of observation; 4) the repeated herbivory events caused low growth in height of the seedlings in general (ICAh = 19.51); 5), the two treatments without the use of hydrogel (T02 and T03) had better performance for all parameters evaluated at the end of the monitoring, with significant differences compared to the other two treatments (00 and 01); In fact, the study proved statistically that the use of hydrogel does not seem to favor the development of seedlings, as well as the use of chemical fertilizers. It can be concluded that Brazil nut tree seedlings have a high survival rate and have high resistance to herbivory, confirming the rusticity of the plant and its potential for use in restoration areas. The development of seedlings was conditioned by the intense attack of herbivory and failures in maintenance tasks, which is why the comparative results of performance between treatments should be considered with caution and reservations.