Introducing non-flooded crops in rice-dominated landscapes: Impact on carbon, nitrogen, and water cycles

The interdisciplinary research unit Introducing Non-flooded crops in rice-dominated landscapes: Impact on CarbOn, Nitrogen, and water cycles (ICON) explores and quantifies the ecological consequences of future changes in rice production. The goal is to provide an understanding of the basic process that is necessary for balancing the revenues and environmental impacts of high yielding rice cropping systems. The ICON project focuses on the consequences of altered flooding regimes, crop diversification, and different crop management strategies on the biochemical cycling of carbon and nitrogen, associated greenhouse gas emissions, water balance, and further ecosystems services of the different rice-based cropping systems.

The ICON research group, based in IRRI, provides the necessary technical and logistic support for the complex ICON experiments. This encompasses (i) field management, (ii) auxiliary measurements according to agreed protocols and (iii) assisting ICON sub-projects in specific tasks. The local team is responsible for all the field operations (pest monitoring, fertilizer applications, land preparation, water monitoring, and irrigation scheduling). The team routinely collects data for documenting agronomic and bio-physical field parameters.

ICON consists of several sub-projects with specific activities.

• SP1 - Microbial N-transformation: Root-associated nitrogen cycling and fixation; Composition of active bacterial communities

• SP2  - Microbial C-transformation: Different pathways to CH4 production;  Molecular analysis of methanogenic microbial community

• SP3 - Soil fauna and function: Interaction of functional groups with focus on C and N pathways; Functional effects of transitions in soil fauna composition

• SP4 - Soil-plant interactions:  Rhizodeposition of C and N; C and N leaching from the rooted surface soil; and Turnover of soil C and utilization of fertilizer N

• SP5  - GHG emissions:  Net-fluxes of CH4, N2O and CO2 ; Spatial and temporal variability of GHG exchange; and Production/ consumption horizons involved in GHG exchange

• SP6 - Biogeochemical cycling: Evaluation and modeling of GHG pollution swapping; Modeling dynamics of soil C and N stocks; and Management strategies to minimize the environmental load

• SP7 - Hydrological cycling: Quantification and modeling of hydrological nutrient fluxes and coupling with biogeochemical model

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