The impact of atmospheric N deposition and N fertilizer type on soil nitric oxide and nitrous oxide fluxes from agricultural and forest Eutric Regosols

Ling Song,Ute Skiba,Bo Zhu,Nicholas Cowan,Peter Levy,Julia Drewer,Minghua Zhou

doi:10.1007/s00374-020-01485-6

Abstract

Agricultural and forest soils with low organic C content and high alkalinity were studied over 17 days to investigate the potential response of the atmospheric pollutant nitric oxide (NO) and the greenhouse gas nitrous oxide (N2O) on (1) increased N deposition rates to forest soil; (2) different fertilizer types to agricultural soil and (3) a simulated rain event to forest and agricultural soils. Cumulative forest soil NO emissions (148–350 ng NO-N g−1) were ~ 4 times larger than N2O emissions (37–69 ng N2O-N g−1). Contrary, agricultural soil NO emissions (21–376 ng NO-N g−1) were ~ 16 times smaller than N2O emissions (45–8491 ng N2O-N g−1). Increasing N deposition rates 10 fold to 30 kg N ha−1 yr−1, doubled soil NO emissions and NO3− concentrations. As such high N deposition rates are not atypical in China, more attention should be paid on forest soil NO research. Comparing the fertilizers urea, ammonium nitrate, and urea coated with the urease inhibitor ‘Agrotain®,’ demonstrated that the inhibitor significantly reduced NO and N2O emissions. This is an unintended, not well-known benefit, because the primary function of Agrotain® is to reduce emissions of the atmospheric pollutant ammonia. Simulating a climate change event, a large rainfall after drought, increased soil NO and N2O emissions from both agricultural and forest soils. Such pulses of emissions can contribute significantly to annual NO and N2O emissions, but currently do not receive adequate attention amongst the measurement and modeling communities.

Highlights

The industrialization of mineral N fertilizer production contributes immensely to global food security, and shares responsibility for a series of environmental pollution issues
Annual wet deposition rates have increased from 13 kg N ha−1 yr−1 in the 1980s to 21 kg N ha−1 yr−1 in the 2000 (Liu et al 2013), and forest ecosystems are changing from naturally N-limited to Nsaturated systems
The focus of this study is to provide new data of soil nitric oxide (NO) and N2O fluxes from an alkaline Regosol, supporting two different ecosystems, a forest and agricultural field, which are adjacent to each other and experience the same climate

Summary

Introduction

The industrialization of mineral N fertilizer production contributes immensely to global food security, and shares responsibility for a series of environmental pollution issues. Annual wet deposition rates have increased from 13 kg N ha−1 yr−1 in the 1980s to 21 kg N ha−1 yr−1 in the 2000 (Liu et al 2013), and forest ecosystems are changing from naturally N-limited to Nsaturated systems. This can lead to negative impacts such as soil acidification and changes in the species composition of flora and fauna (Bobbink et al 2010)

Methods

Discussion

Conclusion