Soil quality indicators in a rhodic kandiudult under different uses in northern Parana, Brazil

Biana Harumi Kuwano,Leandro Godoy,Raquel Cátia Diehl,João Tavares-Filho,Adriana Knob,Marco Antonio Nogueira,Nagib Jorge Melém Júnior,Galdino Andrade Filho,Waldemar Zangaro Filho,Cristina Célia Krawulski,Dáfila Santos Lima Fagotti

doi:10.1590/s0100-06832014000100005

Abstract

Sustainable use of soil, maintaining or improving its quality, is one of the goals of diversification in farmlands. From this point of view, bioindicators associated with C, N and P cycling can be used in assessments of land-use effects on soil quality. The aim of this study was to investigate chemical, microbiological and biochemical properties of soil associated with C, N and P under different land uses in a farm property with diversified activity in northern Parana, Brazil. Seven areas under different land uses were assessed: fragment of native Atlantic Forest; growing of peach-palm (Bactrys gasipaes); sugarcane ratoon (Saccharum officinarum) recently harvested, under renewal; growing of coffee (Coffea arabica) intercropped with tree species; recent reforestation (1 year) with native tree species, previously under annual crops; annual crops under no-tillage, rye (Cecale cereale); secondary forest, regenerated after abandonment (for 20 years) of an avocado (Persea americana) orchard. The soil under coffee, recent reforestation and secondary forest showed higher concentrations of organic carbon, but microbial biomass and enzyme activities were higher in soils under native forest and secondary forest, which also showed the lowest metabolic coefficient, followed by the peach-palm area. The lowest content of water-dispersible clay was found in the soil under native forest, differing from soils under sugarcane and secondary forest. Soil cover and soil use affected total organic C contents and soil enzyme and microbial activities, such that more intensive agricultural uses had deeper impacts on the indicators assessed. Calculation of the mean soil quality index showed that the secondary forest was closest to the fragment of native forest, followed by the peach-palm area, coffee-growing area, annual crop area, the area of recent reforestation and the sugarcane ratoon area.

Highlights

The intensity of soil use may affect soil capacity for maintaining plant yield, carbon (C) and nutrient cycling, and the role of soil as a regulator of the hydrologic cycle
The water content between the permanent wilting point and field capacity is critical for soil biological activities since adequate water availability supports microbial biomass and enzyme activities (Nogueira et al, 2006)
Management practices that contribute to maintaining water in the soil with fewer oscillations in its availability are favorable to the microbial community (Nunes et al, 2009)

Summary

Introduction

The intensity of soil use may affect soil capacity for maintaining plant yield, carbon (C) and nutrient cycling, and the role of soil as a regulator of the hydrologic cycle. The microbial biomass represents the living fraction of soil organic C, along with roots and macrofauna. This biological property is sensitive to changes in soil use, which can be detected prior to changes in physical or chemical properties (Balota et al, 2003; 2004; Kaschuk et al, 2010). The ratio between microbial activity measured as CO2 evolution (Alef, 1995) and microbial biomass gives the metabolic quotient (qCO2) This index brings important insights into the metabolic state of the microbial community, in which high values may be indicative of stress conditions in the microbial community (Anderson & Domsch, 1993)

Objectives

Methods

Results

Conclusion