Soil macrofauna as a bioindicator of soil quality in successional agroforestry systems

Rafaela Martins Da Silva,Sandra Santana De Lima,Gilberto Terra Ribeiro,Rakiely Martins Da Silva,Jheny Kesley Mazzini De Souza,Jianne Rafaela Mazzini De Souza,Guilherme Montandon Chaer

doi:10.33448/rsd-v10i10.19144

Abstract

The objective of this study was to evaluate soil macrofauna as a bioindicator of soil quality in successional agroforestry systems and secondary forests. The study was conducted in the southern lower region of Bahia in Brazil, in two areas: a successional agroforestry system (AFS18) and native forest (NF). AFS18 consists of two species: mahogany (Khaya ivorensis and Khaya grandifoliola), açaí (Euterpe oleracea), cacao (Theobroma cacau) and banana (Musa spp.). Sampling was carried out in the dry (June) and rainy (October) seasons of 2019, and eight soil monoliths were collected in both areas. A total of 889 individuals from the soil macrofauna were sampled. The highest frequency (RF) of taxons occurred in NF in the rainy season, and the groups that stood out were: Oligochaeta with 42% FR in ASF18, Formicide with 33.9% in NF and Isoptera with 58% in AFS18. The macrofauna structure of the soil varied according to the time of collection. The density of macrofauna individuals differed between areas only in the dry season. The highest number of ind.m² was observed in the area NF (378) when compared to ASF18 (196). TOC, Mg2+, Al3+ and CTC were related to AF on both occasions of collection and AFS18 in the rainy season, K+, P and pH were associated with AFS18 in the dry season. The diversity, equitability and richness of the soil macrofauna was greater in AF area. HFA18 in the rainy season was similar to NF, favoring colonization of the area by soil macrofauna organisms.

Highlights

Successional Agroforestry systems (AFSs) can perform these functions more efficiently, as they seek to mimic the structure, diversity and ecological interactions between species similar to natural forest ecosystems (Vieira et al, 2009)
The diversity, equitability and average richness and density of soil macrofauna were favored with higher values observed in the area of native flora (NF) when compared to the studied agroforestry system (AFS18) (Table 1)
The groups Oligochaeta, Isoptera, Formicidae and Coleoptera were highlighted due to their greater abundance in both areas (Table 1), are very important components of soil biota, acting as ecosystem engineers (Oligochaeta, Isoptera and Formicidae) burlap shredders, burlap transformers or predators (Lima et al, 2013). These organisms are capable of modifying pedoenvironmental characteristics, through activities and displacements, producing biopores and aggregates that affect the soil physical properties, such as water infiltration rate mutual influence between organic matter decomposition processes, nutrient cycling and bioturbation are responsible for the balance between the carbon stock in the soil and the emission of greenhouse gases

Summary

Introduction

Successional AFSs can perform these functions more efficiently, as they seek to mimic the structure, diversity and ecological interactions between species similar to natural forest ecosystems (Vieira et al, 2009). Organic matter often added to the soil provides a nutrient-rich substrate for soil fauna (Lima et al 2010; Martins et al.2019) and soil microorganisms, increasing nutrient cycling and soil fertility levels (Cézar et al, 2015) In this context, the benefits of AFS are recognized, it is necessary to monitor these systems considering their composition, the macrofauna soil assessment, together with the activity and abundance of soil communities can be used as indicators of soil quality and functioning (Correia, 2000; Melo et al, 2009). Soil macroinvertebrates actively influence pedological processes through structural and mineralogical transformations (De Oliveira et al, 2014) and improvement of soil hydraulic properties, such as aeration and drainage (Leonard and Rajot, 2001) They act in the formation and stabilization of soil aggregates with implications in flood and erosion control (Brussaard et al, 2007), soil carbon storage and greenhouse gas emissions (Majeed et al, 2014). They are able to indicate changes in physical-chemical characteristics (Velásquez et al, 2010) and structural characteristics of the environment in which they are found (Arias et al, 2015)

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