Enzymatic stoichiometry in tropical soil under pure and mixed plantations of eucalyptus with N2-fixing trees

Author(s)

Arthur Prudêncio de Araujo Pereira ^[1] ; Ademir Sérgio Ferreira Araujo ^[2] ; Maiele Cintra Santana ^[3] ; Antonio Yan Viana Lima ^[4] ; Victor Lucas Vieira Prudêncio de Araujo ^[5] ; Jay Prakash Verma ^[6] ; Elke Jurandy Bran Nogueira Cardoso ^[7]

Affiliation

^[1] Universidade Federal do Ceará. Depto. de Ciência do Solo - Brasil

^[2] Universidade Federal do Piauí. Centro de Ciências Agrárias - Brasil

^[3] Universidade de São Paulo. Depto. de Ciência do Solo - Brasil

^[4] Universidade Federal do Ceará. Depto. de Ciência do Solo - Brasil

^[5] Universidade de São Paulo. Depto. de Ciência do Solo - Brasil

^[6] Banaras Hindu University. Institute of Environment and Sustainable Development - Índia

^[7] Universidade de São Paulo. Depto. de Ciência do Solo - Brasil

• Document type: Journal article
• Source: Scientia Agricola; v. 80, 2022-04-13.

Abstract

ABSTRACT: Soil enzymes play a fundamental role in nutrient cycling in forest systems. The stoichiometry of C, N, and P–acquiring 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 β-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 N–acquiring enzymes were higher in E and E+N, while soil microorganisms invested in P–acquiring 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 P–acquiring enzymes to improve biological N2 fixation promoted by diazotrophic bacteria associated to acacia. (AU)

• FAPESP's process: 16/18944-3 - Climatic changes and energetic efficiency in agriculture: focusing on hydric stress, organic management and soil biology
• Grantee: Elke Jurandy Bran Nogueira Cardoso
• Support Opportunities: Research Program on Global Climate Change - Thematic Grants
• FAPESP's process: 10/16623-9 - Ecological intensification of eucalyptus plantations by association of nitrogen fixing leguminous tree species
• Grantee: José Leonardo de Moraes Gonçalves
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 16/01636-4 - The metagenome of mixed forests of Eucalyptus urograndis: taxonomic and functional diversity of soil microbiome associated with nitrogen cycling
• Grantee: Arthur Prudêncio de Araujo Pereira
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 17/16610-3 - Intercropped plantations of Eucalyptus grandis and Acacia mangium: nitrogen cycle microbiome in the soil and litter interface
• Grantee: Arthur Prudêncio de Araujo Pereira
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate