Location: Delta Water Management Research
Project Number: 6024-13000-004-069-T
Project Type: Trust Fund Cooperative Agreement
Start Date: May 31, 2023
End Date: Oct 1, 2025
The overarching goal of this proposed study is to evaluate N fertilizer management strategies that directly reduce yield-scaled N2O and CH4 emissions in furrow rice systems. The specific objectives are to: 1. To compare seasonal N2O and CH4 emissions from furrow rice fertilized with urea and YUAS40 fertilizer. 2. To measure grain yields from furrow rice with various N fertilization strategies. 3. To determine yield-scaled global warming potentials of furrow rice fertilized with YUAS40.
Mid-South farmers are increasingly adopting furrow irrigation because it allows rice to be grown on more permeable soils and/or steeper slopes than feasible with traditional flooding and reduces soil disturbance and labor associated with installing/removing levees and levee gates. Field studies show non-flooded rice cultivation (aerobic rice) can reduce the total global warming potential (GWP) of rice as compared to continuously flooded rice. However, furrow-irrigated rice in the US Mid-South hold floodwater on the lower portion of the field which creates varying soil moisture conditions across the field and, thus, poses potential variations in total CH4 and N2O emissions. Also, the cycling between wet and dry soil conditions with furrow-irrigation stimulates nitrification and denitrification processes for N2O losses. A recent field study on furrow rice showed 35 times higher N2O emissions in the non-flooded part of furrow field than the continuously flooded rice practice because drying occurred when high amounts of mineral N were present in the soil. Critically, if water and N fertilizers are not appropriately managed together, N2O emissions can be high, negating the benefit of reduced CH4 emissions. This study aims to evaluate N fertilizer management strategies that directly reduce yield-scaled N2O and CH4 emissions in furrow rice systems. Also, this study will generate scientifically sound GHG emission baseline data and efficient N fertilizer management practices that will reduce N2O and CH4 emissions in furrow rice. Seasonal GHG emissions from furrow rice fertilized with Urea-N and YUAS40 fertilizer will be compared.