Resposta à fertilização nitrogenada e estoque de nitrogênio biodisponível em solos usados para plantações de Eucalyptus

Nitrogen balance in soil under eucalyptus plantations

“…However, in Brazil, the N fertilization of these plantations is usually based on generalized NPK formulations, regardless of the actual amount of N that should be applied. This situation arises partially from the inability to predict the actual N contribution of the soil (Pulito, 2009). Gonçalves et al (1996) recommended that the N fertilization of eucalyptus plantations be based on three classes of soil organic matter (SOM) content.…”

Appraisal of the Snap Model for Predicting Nitrogen Mineralization in Tropical Soils Under Eucalyptus

“…Additional N would also have been mineralized at deeper depths. Considering that the N demand by a fast-growing tropical eucalyptus plantation can be a maximum of 163 kg ha -1 yr -1 N (Cromer et al, 1993), it is not surprising that few of the plantations in this study responded to N fertilization (Pulito, 2009).…”

“…These sites have been reported previously as a part of other studies that included an N fertiliser experiment at each site with at least three replicates (Gomes, 2009;Pulito, 2009 (Gonçalves, 2002;Gonçalves et al, 2013).…”

“…Brazil has a large and expanding tropical eucalyptus plantation estate with increasing evidence of N deficiency (Pulito, 2009) and rates of N fertiliser have been raised during the past decade to remedy this deficiency (Gonçalves et al, 2004 currently uses the 3-PG process-based model (Almeida et al, 2010;Stape et al, 2010;Gonçalves et al, 2014), but 3-PG does not specifically include any nutrient. As SNAP was the only model available and largely based on data from the plantation industry, industry partners of this research project were keen to use SNAP to enhance their understanding of NNM and its predictions for their soils.…”

Leaf Total Nitrogen Concentration as an Indicator of Nitrogen Status for Plantlets and Young Plants of Eucalyptus Clones

“…In the rainy season, there is more probability of OM mineralization in the soil and, since the clayey soil had higher organic C concentration (Table 1), a greater total N concentration in the soil was observed (Table 3). High and positive correlations between total N and OM (r = 0.90) and total N and clay (r = 0.94) were found in soils of eucalyptus plantations in the state of São Paulo (Pulito, 2009). The greater total N concentration in clayey soil, as well as other factors (water content in the soil, for example), could favor greater N uptake by plants in the rainy season, and this would reflect greater chlorophyll concentration, since N and chlorophyll concentrations in the leaf are correlated (Turnbull et al, 2007), though not always (Dechen and Nachtigall, 2007).…”