Disponibilidade e eficiência no uso de nutrientes em florestas secundárias sob diferentes níveis de alteração na região de Santarém e Belterra, Amazônia Oriental
We have evaluated the availability and nutrients use efficiency in logged forests (EXP), logged and burned (EXPQ), and recovering forests after deforestation (CR), comparing them with undisturbed (PRI) at Tapajós National Forest. Thus, the soils were sampled following the RAINFOR Project standard...
| Autor principal: | Brunello, Alexandre Tadeu |
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| Grau: | Dissertação |
| Idioma: | por |
| Publicado em: |
Instituto Nacional de Pesquisas da Amazônia - INPA
2020
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| Acesso em linha: |
https://repositorio.inpa.gov.br/handle/1/5119 http://lattes.cnpq.br/5138387082734243 |
| Resumo: |
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We have evaluated the availability and nutrients use efficiency in logged forests (EXP),
logged and burned (EXPQ), and recovering forests after deforestation (CR), comparing
them with undisturbed (PRI) at Tapajós National Forest. Thus, the soils were sampled
following the RAINFOR Project standard protocol. In order to understand the complex
dynamics of P in these forests, phosphorus sequential fractionation was applied
(Hedley, 1982). In addition, nutrients use efficiency was addressed through the
methodology used by Vitousek (1982, 1984). Although soil sum of bases was not
statistically different between studied forests (p > 0.05), it tends to be higher where fire
occurred, which in turn yielded greater pH values in EXPQ and CR forests (p < 0.05),
4.36 ± 0.25 e 4.36 ± 0.21, respectively. Nitrate, exchangeable K and phosphorus
fraction Po NaOH were positively correlated (p < 0.05) with litter production (ρ = 0.67;
ρ = 0.52; ρ = 0.35, respectively), which suggests that such nutrients are strongly
associated with these forests productivity. We did not find differences in contents
neither in soils phosphorus fractions distributions, either individually or in combined
fractions (p > 0.05). Phosphorus use efficiency (EUP) was not different (p > 0.05).
There is a strong evidence that forests studied here are limited by phosphorus, once
there is low contents of this element in the soil, as well low annual return through
litterfall and high efficiency cycling rates, regardless the vegetal cover alterations.
Although a nitrogen use efficiency gradient is still noticeable (p < 0.05), markedly
where the impacts were more drastic (CR), the soil nitrogen supply seems to getting
close to the natural conditions, some time since the disturbances. |