Fertigation is the practice of applying soluble fertilisers dissolved in water through an irrigation system.

David Spencer, Agronomy and Crop Solutions Manager for Yara Fertilizers NZ, explains: “Depending on the irrigation system used, an optimised nutrient programme can be designed to account for key factors such as the crop growth stage, soil type and soil pH. Fertigation programmes offer a flexible and highly efficient way to deliver key nutrients to a crop at the right time with minimal wastage of water and nutrient products.”

Colin Fulford is a director of Omahuri Orchards in Hawke’s Bay where fertigation is applied to some, but not all of their orchard blocks.

Colin says they have been fertigating several apple and stonefruit blocks for a number of years using the YaraTera Kristalon range in conjunction with Calcinit (calcium nitrate).

“I have seen a definite improvement in overall tree heath and fruit quality in the fertigated blocks,” says Colin. “When harvesting a block of fertigated Galaxy apples in February, the trees and crop look better than our non-fertigated blocks.”

Colin notes that it’s not always easy to see a visual response from a fertiliser application. “However, in the case of fertigation we certainly can. We can also adjust fertigation programmes to suit specific requirements based on tree age, crop load, variety and other factors.”

Gary Speers, one of Fruitfed Supplies’ Technical Horticultural Representatives based in Hastings, says over the past few years he’s seen an increase in growers utilising fertigation to apply fertilisers throughout the growing season.

Gary says: “One of the main benefits fertigation offers is that we apply fully soluble and plant-available nutrients exactly when they are required by the plant. We can react quickly to any situation that might require nutrient applications to aid tree health or fruit quality. We have worked with Yara for many years and their YaraTera Kristalon range of soluble NPK fertilisers with various nutrient ratios suit different growth stages or conditions.”

David explains further benefits of fertigation.

“As Colin and Gary have highlighted, efficiency and flexibility are really the key words. Applying water soluble fertiliser is an efficient way to meet the nutritional needs of crops with the correct rate of nutrients applied at the right time. The nutrient uptake by the plant is also efficient with the soluble nutrients applied with water moving rapidly through the plant’s root system for the plant to use as needed. We are all aware of the importance of water use nationally and globally, so every aspect of horticulture where we can improve the efficiency of water use without negatively impacting yield is a factor to consider.”

New technology means irrigation and fertigation systems are becoming more advanced and easier to use. “Combine these improvements with continually expanding knowledge of crop nutrient requirements across a season, we can see that the frequent and targeted application of nutrients through fertigation can create effective nutrition management strategies for your orchard, vineyard or vegetable block.”

David says conventional ground-spread fertilisers have a role in most nutrition programmes. “However, there are other benefits of fertigation such as improved management of mobile nutrients like nitrogen in the soil which minimises losses through leaching while improving plant uptake.

“Fertigated plants generally have increased root mass. This improves their water consumption as this larger root ball has the ability to trap and hold water, which also reduces the potential for leaching."

“We can apply very specific nutrients at specific growth stages to manipulate the crop for fruit quality, uniformity, colour, size and taste.”

Fertigation also helps overcome soil issues such as the pH being too high or low, or light soil structures which drain freely.

“Lastly, with fertigation being applied through the established irrigation system, the application of nutrients does not require additional tractor operations, with associated fuel and labour costs, and machinery wear and tear.”

For specialist advice and a tailored fertigation programme, contact your local Fruitfed Supplies Representative.