No-Till and Solid Digestate Amendment Selectively Affect the Potential Denitrification Activity in Two Mediterranean Orchard Soils

Michele Monti,Giuseppe Badagliacca,Maurizio Romeo,Antonio Gelsomino

doi:10.3390/soilsystems5020031

Michele Monti, Giuseppe Badagliacca + Show 2 more

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https://doi.org/10.3390/soilsystems5020031

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Journal: Soil Systems	Publication Date: May 21, 2021
Citations: 5	License type: CC BY 4.0

Affiliation: University of Reggio Calabria

Abstract

Improved soil managements that include reduced soil disturbance and organic amendment incorporation represent valuable strategies to counteract soil degradation processes that affect Mediterranean tree cultivations. However, changes induced by these practices can promote soil N loss through denitrification. Our research aimed to investigate the short-term effects of no-tillage and organic amendment with solid anaerobic digestate on the potential denitrification in two Mediterranean orchard soils showing contrasting properties in terms of texture and pH. Denitrifying enzyme activity (DEA) and selected soil variables (available C and N, microbial biomass C, basal respiration) were monitored in olive and orange tree orchard soils over a five-month period. Our results showed that the application of both practices increased soil DEA, with dynamics that varied according to the soil type. Increased bulk density, lowered soil aeration, and a promoting effect on soil microbial community growth were the main DEA triggers under no-tillage. Conversely, addition of digestate promoted DEA by increasing readily available C and N with a shorter effect in the olive grove soil, due to greater sorption and higher microbial efficiency, and a long-lasting consequence in the orange orchard soil related to a larger release of soluble substrates and their lower microbial use efficiency.

Highlights

Common tree cultivations in the Mediterranean areas often have to face several degradation processes induced by inappropriate management activities and/or environmental causes, such as soil erosion, soil organic matter depletion, loss of biodiversity, a general reduction in fertility, and diffuse pollution, which lead to limited ecosystem service benefits and increased desertification [1,2]
Our study showed that the application of the improved management practices could lead to increase Denitrifying enzyme activity (DEA) into the soils with dynamics that vary according to the soil type
With regard to no-till use, our study suggests that higher bulk density, lower porosity, and reduced soil aeration, in the olive grove, and a promoting effect on soil microbial growth, in the orange orchard, were the main factors that determined an increase in soil DEA, respectively

Summary

Introduction

Common tree cultivations in the Mediterranean areas often have to face several degradation processes induced by inappropriate management activities and/or environmental causes, such as soil erosion, soil organic matter depletion, loss of biodiversity, a general reduction in fertility, and diffuse pollution, which lead to limited ecosystem service benefits and increased desertification [1,2]. These processes, in turn, negatively affect their production and, subsequently, farmers’ income. Denitrification represents an important process that can affect soil N balance, agronomical N use efficiency and, even more seriously, the release of

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