Just Avocados orchard productivity manager Erica Faber discussing avocado tree nutrient requirements.

The importance of the interrelation and balance between levels of hormones, nutrients and carbohydrates – and their effects on an avocado tree's performance – were emphasised by Just Avocados' orchard productivity manager Erica Faber at three recent field days.

'It's important for growers to understand that every action they make triggers a hormone reaction in the tree – we want our growers to know that what they are doing has the desired outcome.

'You always have to ask the question – is what I'm doing giving me the returns I want? If not then you need to do something different or you are not getting the best returns for your money,” says Erica.

The sessions, presented in Whangarei, Pukenui and Whakamarama focused on autumn and winter management practices for ensuring optimal flowering and fruit set for the 2018-2019 crop.

They set the scene for growers as to what Just Avocados' management programmes going forward will be based on.

'We are working with growers to set their orchards up for a good 2018-2019 crop set; we started with the basics about how the tree grows and responds to the management techniques we introduce in relation to hormones, nutrition and carbohydrates.

'In order to supply our trees with the correct resources it needs when it needs it, we first need to understand the tree phenology so we can be two steps ahead.

Hormone triggers

'At this time, there is a seasonal change of lower temperatures and shorter day lengths and flower initiation is being triggered within the tree. We need to be supporting this.

'Hormones trigger the transition from vegetative to floral buds but it is the nutrient levels and balances that drive this reaction and the carbohydrate levels that determine the stamina of this reaction.

'This pre-flowering and flowering stage is one of those critical stages we, as growers, need to ensure the tree has all the resources it needs in order to optimise production.”
Erica advocates foliar spraying to support the tree through this critical period of specific nutrient demand for bud differentiation, fruit set and fruit growth.

'Solid fertiliser is a traditional choice but foliar application can overcome soil fertilisation limitations such as leaching, runoff, nutrient fixation in the soil, limited root activity due to low winter temperatures or poor root health, antagonism between certain nutrients, pH limitations, soil moisture levels etc.

'Foliar fertiliser application also provides a more timely and immediate method for delivery of specific nutrients at critical stages of plant growth.

'Foliar nutrition programmes are therefore valuable supplements to soil applications,” says Erica.

Comments have been made about the waxy nature of the avocado leaf inhibiting uptake of nutrients, but Erica says this is an old belief.

Optimum absorption

'The leaves, as well as fruit and flowers, absorb the nutrients and modern foliar fertilisers are manufactured using very high grade technical elements to ensure optimum absorption.” She also advises the use of adjuvants with foliar applications.
Whakamarama avocado grower Quinton Lankshear hosted a Just Avocados field day in March was impressed with the information shared.

'We planted 1350 Hass on Dusa in December and I want to manage these to their best potential from the start. Erica's information is refreshing and it makes sense to me, it's practical and not just the same old stuff,” says Quinton. 'The biggest thing I took out of Erica's session was how the processes in the soil slow down over the cooler months and the mainstream solid fertilisers we are putting on are not taken up as effectively.”
Just Avocados advises that consultation on specific orchard requirements is necessary before implementing any programme.