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

作者：Arthur Prudêncio de Araújo Pereira, Ademir Sérgio Ferreira de Araújo, Maiele Cintra Santana, Antonio Yan Viana Lima, Victor Lucas Vieira Prudêncio de Araújo, Jay Prakash Verma, Elke Jurandy Bran Nogueira Cardoso · 发表于：Scientia Agricola · 年份：2022 · DOI：10.1590/1678-992x-2021-0283 · 被引用次数：9 · 研究领域：Soil Carbon and Nitrogen Dynamics、Plant nutrient uptake and metabolism、Soil and Water Nutrient Dynamics

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 biologica...