There is a huge amount of agriculture in the California desert in the south around the Salton Sea. The "sea" itself was created by accident when the Colorado River irrigation channel broke and the river was diverted into the Salton Sink over 100 years ago. It has shrank in size but agricultural runoff keeps it from completely drying. It is also full of pesticide and fertilizer residue.
The Central Valley extends north to Sacramento and there are crops grown through the entire area but the far south is so warm even in winter that they can grow crops year round. A large amount of vegetables that people in the US eat in winter come from this area.
Take a look at the google satellite view
https://maps.app.goo.gl/Nc1Pno74iYmQBERKA
The Central Valley extends north to Sacramento and there are crops grown through the entire area but the far south is so warm even in winter that they can grow crops year round. A large amount of vegetables that people in the US eat in winter come from this area.