Methane emissions from paddy rice soils under alternative irrigation management

Introduction

To meet the food demands of a growing world population, world cereal production must increase by 1-3% yr-1 until 2025. As rice consumption is consequently expected to increase by 50%, rice production must come primarily from higher yields on a shrinking land area, in particular by irrigated rice (producing 75% of the world’s rice supply). Flooded rice paddies one of the major biogenic sources of the methane (CH4). Emissions are strongly influenced by the applied water regime. In a context of decreasing water availability due to climate change, alternative irrigation management (AIM) techniques are currently being applied in paddy rice production. However, an integrated and process based understanding of AIM and its effect on greenhouse gas (GHG) emissions is currently lacking.

Objectives

Together with the Swiss, Italian and American partners of the GreenRice Consortium, we will target several knowledge gaps in C, N and Fe-cycling processes, relevant to GHG production under AIM in floodplain soils. I will focus more specifically on the role of Fe and dissolved organic matter (DOM) availability in the evolution of the redox potential in young floodplain soils under AIM as well as under continuous flooding (CF). A second  objective is to further insights on how CH4 production in paddy soils results from the net result of CH4 genesis and oxidation for both alternative as well as conventional water management techniques.
Together with the findings of the other GreenRice Consortium partners (mainly focusing on N2O emission-pathways), these analyses will be used to fine-tune a biogeochemical model with the aim of simulating global warming potential (GWP) budgets for lab and field experiments in paddy soils for several AIM scenarios.

Researcher: ir. Sofie Pierreux
Period: 2014-2018
Financing body: EU FACCE-JPI
Promoter: Prof. dr. ir. Steven Sleutel