Location: Delta Water Management Research
Project Number: 6024-13000-004-082-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Mar 1, 2024
End Date: Feb 28, 2029
Objective:
Contribute to the Inflation Reduction Act Measurement Monitoring Reporting and Verification Action Area 2-Cropland through measurement of cropland methane and nitrous oxide emissions.
Approach:
Precision leveling of rice fields improves rice irrigation management efficiency and control. One study pair will be executed on two fields that were precision graded to zero slope. On these fields, eddy covariance (EC) towers have been deployed since 2015. Research will continue to evaluate the challenges and benefits of implementing Alternate Wetting and Drying compared to conventional, delay flooded (CDF) rice. Two trace gas instruments will be purchased through this agreement to allow for geo-located, short closure time, and field-rugged measurements of methane and N2O. These measurements will be collected with chambers on two field pairs near the EC tower site. At these sites, CDF will be compared to AWD. Site selection will target clay content, with one field pair higher and one lower than the EC tower clay content. To minimize field disturbance, a boardwalk we will be installed next to 12 collars as six pairs. Six flux measurements can be made from each field in each week, with weekly rotation of the collars from each pair, to minimize damage of the plants in each collar system. Sampling will be conducted during the rice growing season at 2-7 day intervals to capture event-related emissions such as the final dry-down period before harvest, and the campaigns will run from before the first flood to after the final dry-down. In each of the first six years of the project, 20 soil samples will be collected for analysis of C/N ratio and LOI. These will be collected near the eddy covariance towers (5 locations per tower, 2 depths (0-10 cm, 10-20 cm), and 2 towers) to link GHG flux rates to soil substrate status.
