Changes in Soil Chemical Properties Due to Long-Term Compost Fertilization Regulate Methane Turnover Related Gene Abundances in Rice Paddy

Kido Park,Denver I Walitang,Chungwoo Kim,Hyenchung Chun,Sanghun Lee,Aritra Roy Choudhury,Tae-Young Heo,Tongmin Sa,Yi Lee

doi:10.3390/app12052652

Abstract

Maintaining rice yield, soil function, and fertility are essential components of long-term compost fertilization. However, paddy fields are major sources of anthropogenic methane emissions. The aim of the study is to evaluate the changes in soil chemical properties and their concurrent impact on the abundance of methanogenesis (mcrA) and methane oxidation (pmoA) related genes among compost (Com), NPK+Compost (NPKCom), and unfertilized (NF) fallow paddy fields under long-term compost fertilization. Results showed that compost and NPK+Compost fertilization altered the soil chemical properties of paddy fields with a significant increase in the functional gene abundance potentially associated with Methanobacteriaceae for mcrA (1.23 × 106 to 3.84 × 106 copy number g−1 dry soil) and methane oxidizing bacteria such as Methylomonas and Methylobacter for pmoA (1.65 × 106 to 4.3 × 106 copy number g−1 dry soil). Ordination plots visualized these changes, where treatments clustered distinctly indicating that Com and NPKCom treatments were characterized by paddy soils with elevated OM, TN, K and P content and higher abundances of methanogenesis and methane oxidation related genes. The study showed that long-term compost fertilization resulted in paddy fields with high nutrient content and high gene abundance, attributed to methanogens and methane oxidizing bacteria that responded well with compost fertilization. These results indicated the potential of these fallow paddy fields for methane emission and methane oxidation and that they are ‘primed’, potentially influencing subsequent paddy field responses to long-term compost application.

Highlights

Climate change and global warming are two of the most important environmental issues that mankind must overcome
The significant increase in both mcrA and pmoA gene abundance in compost-fertilized fallow paddy fields in the current study indicated their potential for enhanced methanogenesis and methane oxidation
This study showed that long-term compost fertilization containing cattle manure and rice straw or a combination of NPKCom—chemical fertilizer (NPK) and compost fertilization increased the organic matter (OM), total nitrogen (TN), P2O5 and K content in the paddy fields

Summary

Introduction

Climate change and global warming are two of the most important environmental issues that mankind must overcome. Soil quality evaluation, previously based mainly on productivity and economic value, needs to incorporate soil physicochemical and microbial components as critical indicators of sustainable agriculture to mitigate environmental issues [1–3]. Methane as a greenhouse gas is a major factor in global warming [4]. The global methane emissions in 2017 reached a record with 600 Tg CH4 yr−1 of which 61% was anthropogenic primarily from agriculture-related sources [5]. Rice paddies are major sources of methane, generating approximately 11% of global anthropogenic methane emissions [6,7]. Methane emission dynamically changes in different soil types under aerobic and anaerobic states dictated by the balance of methane production through methanogenesis and methane oxidation [8]

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Conclusion