• Irrigation
• Nutrition
• Pruning 
• Pest and Disease Control

Irrigation

"A grove without an effective irrigation system is unlikely to deliver consistent yields year after year. Many growers still underestimate the water needs of olive trees, and few actually monitor soil moisture levels. This is why so many groves have never achieved a commercial crop."  Marcelo Berlanda Specialist Olive Consultant

Water stress negatively affects flowering, fruit set, oil accumulation (oil production), fruit size (table olives), fruit quality, and overall tree health. However, many growers lack a proper system to monitor soil moisture or manage irrigation effectively. 

Marcelo recommends:

"Growers should inspect soil moisture weekly during spring and summer, and every two weeks in autumn and winter. Use a shovel to dig at least 400mm under the tree canopy to check moisture. If the soil is hard to dig, it’s too dry – even if the canopy shows no visible signs of stress." 

Advanced soil moisture monitoring tools can also provide reliable data on a digital display or computer dashboard. 

For optimal grove health, growers must consistently check soil moisture and prevent water stress.

Nutrition

As discussed previously, taking leaf samples is essential to assess your trees’ nutritional status. This information guides the creation of a fertiliser program, a critical component for boosting or maintaining yields.

Typically, no fertiliser is needed in winter, unless you’re addressing soil amendments. However, some groves have severe nutrient deficiencies requiring fertiliser even in winter. Where proper irrigation systems aren’t in place, growers must broadcast fertiliser before rain to allow rainfall to incorporate nutrients into the soil profile, an inefficient use of resources but often the only option.

When applying fertiliser in these conditions, target the area beneath the canopy and, if possible, cultivate the soil to improve incorporation and reduce product loss.

Olives need four essential nutrients: Nitrogen, Phosphorus, Potassium, and Calcium. Check product labels carefully. As a general guideline, aim for:

• Nitrogen 15%
• Phosphorus 5% or less
• Potassium 10% or less
  
• Calcium 2% or less
  

Pruning

Avoid pruning during the coldest part of winter and when it’s wet or foggy to reduce the risk of bacterial and fungal disease spread.

The main goals of pruning are to remove dead wood, reduce canopy size, restore tree balance, encourage healthy new growth, and increase fruit set in spring.

Tip: After pruning, apply a copper-based spray to protect wounds from infection by fungi and bacteria.

Pest and Disease Control

Pest and disease management is crucial for sustaining yield and tree health. Winter’s colder temperatures reduce insect activity, offering a prime time to tackle pest issues.

Set up a comprehensive Pest and Disease Monitoring Program. During winter, check marked trees (previously affected by pests or diseases) every two weeks; in spring, check weekly. Look under leaves and on new growth for signs like crawlers, yellow spots, black sooty mold, or anything unusual.

Proactive, weekly management is essential for a successful grove.

If you need further assistance, please contact us.

In the lead up to flowering, you need to ensure your trees have adequate nutrition, particularly of Boron and Calcium. ?A lack of Boron?and Calcium may lead to decreased fruit set, oil quality and oil stability.

The application of Boron?and?Calcium?can never be overstressed. ?It is a requirement for your trees.

In Brief

A study on olive trees has looked at different application rates of Boron and Calcium and the effects on fruit set, fruit oil and oil chemical characteristics.

The rate of 100ppm of Boron?and 2% Calcium?was applied at full bloom and the 2nd application at 15 days later.  Trees were sprayed with nutrient solution till run off.

Fruit Set %

Trees in this study showed a higher fruit set. ?Results also confirm the role of Boron?and?Calcium?nutrients in improving fruit set of olive flowers.

From the overall data, the two studied nutrients effectively increased fertilisation either through controlling pollen germination on the stigma or growth of pollen tube through the style. ?Therefore, the subsequent increase in fruit set % was observed.

Fruit oil %

Furthermore, the effects could also be seen in increased fruit oil content. ?This increase reached a significant level in most cases.

Oil Chemical Characteristics

Peroxide Value

The study of the application of Boron?and?Calcium?at the same rate noted above greatly decreased the peroxide value in the cultivars studied.