Enzymatic stoichiometry in tropical soil under pure and mixed plantations of eucalyptus with N2-fixing trees
Pereira, Arthur Prudêncio de Araujo; Araujo, Ademir Sérgio Ferreira; Santana, Maiele Cintra; Lima, Antonio Yan Viana; Araujo, Victor Lucas Vieira Prudêncio de; Verma, Jay Prakash; Cardoso, Elke Jurandy Bran Nogueira.
Sci. agric;
80: e20210283, 2023. tab, graf
Artigo
em Inglês
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| ID: biblio-1367242
Resumo
Soil enzymes play a fundamental role in nutrient cycling in forest systems. The stoichiometry of C, N, and Pacquiring enzymes has been used to indicate nutrient limitation in the soil. However, the enzymatic stoichiometry remains poorly understood in pure and mixed eucalypt plantations. Thus, this study aims to assess the activity of enzymes in the soil to address the hypothesis that the introduction of N2-fixing trees could influence the enzymatic stoichiometry on C, N, and P cycling. The activity of ß-glucosidase (BG), urease (U), and acid phosphatase (AP) was assessed in soil (0-20 cm depth) of pure Eucalyptus grandis without (E) and with N fertilization (E+N), and a mixed system with E. grandis and Acacia mangium (E+A), and a pure A. mangium (A) plantation at 27 and 39 months after planting. The activities of BG/U, BG/AP, and U/AP were used to calculate the enzyme C/N, C/P, and N/P ratios, respectively. Rates of Nacquiring enzymes were higher in E and E+N, while soil microorganisms invested in Pacquiring enzymes in A and E+A. The vector length and angle demonstrated that C demand by microorganisms does not change in relation to N and P, regardless of the treatment. However, N demand decreased in relation to P in A and E+A (mainly at 27 months). Our results suggest that enzymes activity in pure eucalypt systems is limited for their soil-litter nutrient contents. At the same time while acacia and mixed plantation seem to invest in Pacquiring enzymes to improve biological N2 fixation promoted by diazotrophic bacteria associated to acacia.
Biblioteca responsável:
BR68.1
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