Soil moisture monitoring for olives

Olives are a hardy, drought-tolerant crop that recovers quickly from water stress. So why use soil moisture monitoring on olives?

Californian research has shown that when irrigation is applied above that of rainfall, olive and olive oil yields increase significantly. It is not enough to have the trees survive for a business to do well. In drought scenarios, like those currently being experienced in California, efficient application of water maximises the benefit of irrigation for olives.

Soil moisture monitoring with wildeye can help determine when irrigation is required to minimise stress and maximise yields. The service uses crop and soil data from the Food and Agriculture Organization of the United Nations and the US Department of Agriculture to guide the placement of probes and give an estimate of your soil’s water-holding capacity. The online and up-to-date graphs allow growers to make decisions about when to apply just enough water to fill the rootzone and minimise drainage.

Californian research also suggests that replacing up to 0.75 times evapotranspiration will result in maximum yields for olives. However, for oil production, reducing total irrigation applied by a further 30–40% results in oil that has a better balance of pungency and bitterness, has pleasant fruitiness, holds both ripe and green character, has more complexity and depth and boasts higher polyphenol content.

Grower John Copeland of Rancho Olivos in the Santa Ynez Valley installed a wildeye in August 2015. Prompted by the higher-than-average temperatures and the drought conditions California was experiencing, he hoped wildeye would give him some insight of when to water.

“The unit is working great,” Copeland said. “It is very cool to see how it monitors over time. Wildeye really helps me keep an eye on our orchards and when to irrigate. We have experienced quite a lot of wind, which can quickly dry out the trees.”

Maintaining good soil moisture is critical in three growth stages of most fruit trees. These include spring when the trees are in bloom, flowering and fruit set, then again during fruit ripening. When Rancho Olivos olives were in bloom, Copeland noted, “It is great being able to keep the trees from becoming stressed, and knowing when to provide them with a drink of water is extremely important at this point.”

At the end of harvest, Copeland commented, “Our harvest has been a good one. Keeping track of the soil moisture has been really helpful during this part of the drought. It has helped us manage our water use more efficiently.”