This is the time of the year to check your irrigation system. Does it need repairs, modifications, or improvements? Are there leaks? Does it need to be set up or cleaned out? Is it turned off when it's raining? Do you have the proper frequency and duration for watering your pastures and crops?
Pastures may not need irrigation yet – check to be sure you are not watering unnecessarily. Look at your soil and don't start watering until your soil needs it. Evaluate soil moisture in your crops.
As the season progresses, keep a close eye on your perennial and tree crops. Both drought stress and excess water can cause root damage.
Below are resources to help you set up, evaluate and improve your irrigation system.
BMPs for Water Quality http://ucanr.edu/sites/placernevadasmallfarms/files/170697.pdf
Center for Irrigation Technology http://www.wateright.org/
California Irrigation Management Information System (CIMIS) http://www.tid.org/water/water-management/california-irrigation-management-information-system-cimis
NRCS Estimating Soil Moisture by Appearance and Feel https://nutrientmanagement.tamu.edu/content/tools/estimatingsoilmoisture.pdf
UC Drought Management http://ucmanagedrought.ucdavis.edu/
ATTRA Irrigation Efficiency https://attra.ncat.org/attra-pub/farm_energy/irrigation.html
Resources for pasture irrigation:
Drought Tip: Managing Irrigated Pasture during Drought http://anrcatalog.ucanr.edu/Details.aspx?itemNo=8537
Establishing and Managing Irrigated Pasture for Horses (and other pastured animals) http://anrcatalog.ucanr.edu/Details.aspx?itemNo=8486
Management Options to Reduce Pollutants in Runoff from Irrigated Pastures http://anrcatalog.ucanr.edu/Details.aspx?itemNo=6590D