This alfalfa site is on Bouldin Island, located between Rio Vista and Lodi, in the Sacramento-San Joaquin Delta. The land is managed by Metropolitan Water District.

https://ameriflux.lbl.gov/sites/siteinfo/US-bi1

This site is the second reference agricultural site we are operating. What distinguishes this site is the fact it is a perennial crop and a nitrogen fixer.  It experiences a long growing season and about 5 harvests per year. Hence, we can study how weather and changing leaf area index affects carbon, water and energy fluxes.

This site has been ideal for micrometeorological studies due to its flat terrain, extended footprint and steady winds from the west.  This site has been subject of a number of field studies associated with the NASA ECOSTRESS project. They include an advection study and tracer release of methane to test flux footprint models.

Wang, Tianxin, Kanishka Mallick, Joseph Verfaille, Daphne Szutu, and Dennis Baldocchi. "Water scarcity in semi-arid California compromises perennial alfalfa’s high yield and carbon sinking potentials." Agricultural Water Management 308 (2025): 109284. https://doi.org/10.1016/j.agwat.2024.109284

Wang, T., et al. (2024). "How advection affects the surface energy balance and its closure at an irrigated alfalfa field." Agricultural and Forest Meteorology 357: 110196. https://doi.org/10.1016/j.agrformet.2024.110196

Rey-Sanchez, C., et al. (2022). "Detecting Hot Spots of Methane Flux Using Footprint-Weighted Flux Maps." Journal of Geophysical Research: Biogeosciences 127(8): e2022JG006977. https://doi.org/10.1029/2022JG006977

In recent years, the field was plowed and replanted with wheat one year (2024) and corn another (2025).  The farmers plan to replant alfalfa again.