Relationship between Leaf Micro- and Macro-Nutrients in Top Canopy Trees in a Mixed Forest in the Upper Rio Negro in the Amazon Region

Abstract

The mixed forests of the upper Rio Negro at the northern of the Amazon basin grow in oxisol soils that are extremely infertile. These areas exhibit deficiencies in several macro-nutrients, and may also be characterized by the shortage or toxic excess of some micronutrients. The overall goal of this research is to collect more comprehensive information regarding the micronutrient composition of the upper Rio Negro forests as well as discern the relationship between leaf micro-and macro-nutrients that may contribute to the homeostasis and balance of the ionome. Firstly, the nutrient composition within the oxisol soil and leaf tissues of two top canopy tree species from the mixed forests was determined. We then analyzed the relationship between leaf micronutrient composition with N and P levels of the two species and that of species inhabiting the Amazon caatinga. Extractable soil Zn, B, Mn and Cu were very low in the mixed forest. In contrast, Fe and Al levels were potentially toxic. The analysis of leaf N/P ratios revealed for the first time the co-limitation of N and P in the mixed forest. This contrasts with species from the adjacent Amazon caatinga toposequence that are characterized by strong N limitation. All micronutrients within leaves of species inhabiting the mixed forest were also found to have low concentrations. Moreover, Fe and Al were detected at concentrations well below those reported for accumulator species. This suggested that leaf ion homeostasis was maintained under potentially toxic soil Fe and Al conditions. Leaf micronutrient (Fe, Zn and B) contents mirrored that of leaf N and P contents, and comparable Fe/N, Fe/P, Zn/N, Zn/P, B/N as well as B/P ratios were found across species and forest types. Therefore, forest species exhibited the capability to maintain leaf nutrient balances under soil conditions with deficient or toxic levels of micronutrients.

Nutritional Evaluation of Millet Plants Grown in Soils Fertilized With Organic Wastes From Different Sources

“…The highest P contents with the OMR of 20% were found in plants in soils with SM, and the lowest in plants in soils with BM; and the highest P contents with the OMR of 40% were found in plants in soils with PL, and SM (Table 3). According to Sobrado (2014) the N and P are co-limiting macronutrients in the crops that growing in oxisol soil.…”

Anais do Congresso Plantações Florestais.

“…Embora muitos estudos avaliem a deposição da serapilheira e o retorno dos nutrientes em ecossistemas florestais (Corrêa et al, 2013), poucos estudos relatam sobre os micronutrientes nas (Corrêa et al, 2016). Contudo, para o correto entendimento da ciclagem de nutrientes em um ecossistema, faz-se necessário a avaliação dos micronutrientes (Sobrado, 2014). Mesmo que exigido em pequenas quantidades quando comparado com os macronutrientes (Moretti et al, 2011), a deficiência dos elementos B, Cu, Fe, Mn e Zn, diminui o crescimento das plantas (Sobrado, 2014), entretanto uma maior preocupação seja dada ao excesso dos mesmos, especialmente de Mn e Fe, que podem levar à toxicidade, desenvolvendo problemas relacionados à produção, desenvolvimento e crescimento .…”

“…Contudo, para o correto entendimento da ciclagem de nutrientes em um ecossistema, faz-se necessário a avaliação dos micronutrientes (Sobrado, 2014). Mesmo que exigido em pequenas quantidades quando comparado com os macronutrientes (Moretti et al, 2011), a deficiência dos elementos B, Cu, Fe, Mn e Zn, diminui o crescimento das plantas (Sobrado, 2014), entretanto uma maior preocupação seja dada ao excesso dos mesmos, especialmente de Mn e Fe, que podem levar à toxicidade, desenvolvendo problemas relacionados à produção, desenvolvimento e crescimento . A área do povoamento possui relevo plano, com altitude média de 34 m, sendo o solo caracterizado como Argissolo Amarelo Distrocoeso típico A moderado, bem drenado com textura média/argilosa (Embrapa, 2013).…”

Serapilheira e micronutrientes em povoamento de eucalipto

“…Embora muitos estudos avaliem a deposição da serapilheira e o retorno dos nutrientes em ecossistemas florestais (Corrêa et al, 2013), poucos estudos relatam sobre os micronutrientes nas (Corrêa et al, 2016). Contudo, para o correto entendimento da ciclagem de nutrientes em um ecossistema, faz-se necessário a avaliação dos micronutrientes (Sobrado, 2014). Mesmo que exigido em pequenas quantidades quando comparado com os macronutrientes (Moretti et al, 2011), a deficiência dos elementos B, Cu, Fe, Mn e Zn, diminui o crescimento das plantas (Sobrado, 2014), entretanto uma maior preocupação seja dada ao excesso dos mesmos, especialmente de Mn e Fe, que podem levar à toxicidade, desenvolvendo problemas relacionados à produção, desenvolvimento e crescimento (Lopes et al, 2007).…”