Gross Ammonification and Nitrification Rates in Soil Amended with Natural and NH4-Enriched Chabazite Zeolite and Nitrification Inhibitor DMPP

Sophie Zechmeister-Boltenstern,Markus Gorfer,Barbara Faccini,Axel Mentler,Katharina Maria Keiblinger,Giacomo Ferretti,Evi Deltedesco,Jennifer Fritz,Giulio Galamini,Massimo Coltorti

doi:10.3390/app11062605

Abstract

Using zeolite-rich tuffs for improving soil properties and crop N-use efficiency is becoming popular. However, the mechanistic understanding of their influence on soil N-processes is still poor. This paper aims to shed new light on how natural and NH4+-enriched chabazite zeolites alter short-term N-ammonification and nitrification rates with and without the use of nitrification inhibitor (DMPP). We employed the 15N pool dilution technique to determine short-term gross rates of ammonification and nitrification in a silty-clay soil amended with two typologies of chabazite-rich tuff: (1) at natural state and (2) enriched with NH4+-N from an animal slurry. Archaeal and bacterial amoA, nirS and nosZ genes, N2O-N and CO2-C emissions were also evaluated. The results showed modest short-term effects of chabazite at natural state only on nitrate production rates, which was slightly delayed compared to the unamended soil. On the other hand, the addition of NH4+-enriched chabazite stimulated NH4+-N production, N2O-N emissions, but reduced NO3−-N production and abundance of nirS-nosZ genes. DMPP efficiency in reducing nitrification rates was dependent on N addition but not affected by the two typologies of zeolites tested. The outcomes of this study indicated the good compatibility of both natural and NH4+-enriched chabazite zeolite with DMPP. In particular, the application of NH4+-enriched zeolites with DMPP is recommended to mitigate short-term N losses.

Highlights

Unsustainable farming practices are unquestionably impairing soil, water, and air quality as a consequence of nutrient leaching and emission of harmful greenhouse gases (GHGs)
nitrous oxide reductase (Nos) significant differences were observed between CNTR, NZ, and CZ for pH (p > 0.05), while significant differences were accounted for electrical conductivity (EC) (p < 0.05): the NZ treatment was characterized by lower EC, while CZ showed the higher EC
Significant differences were observed in nitritebetween reductasewith (nirS) and nosZ abundance among the treatments: CZ showed a lower abundance of these functional genes compared to the CNTR (p < 0.05)

Summary

Introduction

Unsustainable farming practices are unquestionably impairing soil, water, and air quality as a consequence of nutrient leaching and emission of harmful greenhouse gases (GHGs). This deterioration of natural resources makes the achievement of sustaining the future food demand for the global population improbable. The development of strategies for reducing nutrient losses from agroecosystems and increasing the fertilizer and nutrient use efficiency (FUE and NUE) by crops is crucial [2,3,4,5,6]. The use of soil amendments is recognized as a valuable possibility to improve soil properties, crop yield, and reduce nutrient losses from the soil system [1,7,8]. A wide spectrum of soil amendments is employable in the agricultural context, ranging from organic (e.g., manure, biochar, etc.) to inorganic (e.g., lime, natural zeolites, etc.) materials [1,9,10,11]

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