Adubação verde com ingá (inga edulis) em solo latossolo amarelo de quintais agroflorestais na Amazônia Central

Abstract

The amazonian homegardens on terra firme are in general placed on distrofic soils with aluminum toxicity, with high acidity, and progressive decline of productivity, due to low resources availability. The experiment was developed to evaluate manuring forms between five treatments: control, chemical fertilization and deposition of pruned biomass of ingá (Inga edulis) with 3,69% N, in the recommendations of 15, 30 and 45 t ha-1, applied in plots of 40 m2. The soil’s chemical characteristics were accompanied in three samplings, in the beginning, 4 and 6 months after the application of the treatments, in the depths 0-10 and 10-20 cm. The chemical fertilization was constituted by N, P, K, calcined dolomite and micronutrients in FTE form. Jucá (Libidibia ferrea var. ferrea) were used as indicative plants, harvested in lines inside the plots with 1,5 m among plants. The experiment was arranged in randomized blocks in factorial arrangement 5 x 3 x 2, considering manuring forms, period and soil’s depth, with three replicates. The growth of jucá was accompanied by height measures, basis diameter and monthly estimates of growth, with randomized block and three replicates of 4 plants. After six months of 45 t ha-1 of inga’s pruned biomass application, it was identified an increase of nutrients availability in the soil, with reduction of acidity and Al3+ toxicity. The C:N ratio medium values of 10,63 supported mineralization processes. The initial benefits to the soil’s depths of 0-10 and 10-20 cm showed normal distribution as expected. Jucá’s growth evidenced the benefits of cover green manuring practice. In six months, the jucá plants presented larger growth in height and basis diameter, with monthly increment of height growth of 12,5 cm month-1 in the plots that received higher amounts of green manure. In the succeeding months, the conventional chemical fertilization promoted effects comparable with the 45 t ha-1 green manure of ingá biomass, although its localized distribution when applied in crowning, disregards the potential of homogeneous liberation of nutrients to the soil wich received organic matter. The homegardens researched presented agrobiodiversity resources commonly maintained by farmers, wich the most occurring botanical families were Anacardiaceae and Arecaceae, prevailing the native ones, with emphasis to the fruit trees cupuaçu and mari.