After the Rain Cometh the Irrigation Season

Soil moisture can be estimated by feel and appearance.With the wet winter and possible spring storms, the question of when to begin irrigating can sometimes be a tough one to answer. To address that question, Almond Board of California (ABC) put together a worksheet,  “Determining When to Begin Irrigation,” that can help guide growers to decide based on their individual conditions.

When determining the right time to begin irrigation, growers should consider the crop demand or ETc (crop evapotranspiration) and soil water-holding capacity, and estimate the effective rainfall for the season. 

“My favorite tools to use this time of year are the document ‘Estimating Soil Moisture by Feel and Appearance’ and my soil auger,” said Spencer Cooper, ABC’s senior manager, Irrigation and Water Efficiency. “Once you have determined what your soil type and water-holding capacity are, you can then start to figure out the effective rainfall.”

As an example, if you identify that you have a sandy-loam soil, your soil can potentially hold up to 1.5 inches of water per foot of soil; and if you have an effective root zone of 4 feet, you would then have 6 inches of available water capacity. "Determining When to Begin Irrigation" has a handy chart that can help give you the breakdown for each month.

“It is important to consider all the variables in an effort to maximize your irrigation efficiency during early spring applications,” Cooper noted. If you have questions or would like more clarification or even a farm visit, please do not hesitate to reach out to Cooper at either or (209) 343-3231.