Avocado fertilization to optimize productivity in a subtropical environment
Ran Erel, Arnon Dag, Dafna Ziv and Alon Ben-Gal
Abstract
Avocado fruit is known for its high nutritional value and health properties. Consequently, global demand is increasing and vast investment has been made in new plantations worldwide. ‘Hass’ is the leading variety globally, and therefore dominant in new plantations. Unfortunately, in subtropical climates (e.g. Spain, Israel, California, Australia and South Africa) Hass productivity is low, about 13-ton ha-1 and trees are highly susceptible to cold, radiation and frost stresses. Any means that may increase productivity towards 20-ton ha-1 (achieved in the ‘green’ varieties) is highly desired and will be economically rewarded.
Avocado fertilization management and recommendations are largely based on extensive study from the 80-90s’ while modern orchard layout had been significantly modified in the past two decades. That requires re-evaluation of fertilization practices in light of the changes in modern agro-system.
To achieve this objective, on 2018 we’ve established two experimental setups: (1) controlled trial in large containers and (2) field trial in mature avocado orchard. In both experiments we monitor plants developmental and reproductive parameters in response to nitrogen (N), phosphorus (P), potassium (K) and micro-elements.
The advanced container experimental setup was successfully used to study olive (Erel et al., 2013), pomegranate (Lyu et al., 2020; Lazare et al., 2020) and almond (Sperling et al., 2019) responses to fertilization. In the first couple of years, we monitored tree growth, physiological parameters and productivity. Our results indicated avocado requirements for N are substantially higher than many fruit-trees tested. Both vegetative and reproductive traits were enhanced by N up to 80 mg l-1 while higher level caused reduction in growth. P, K and micro-elements had minor effect on growth while productivity seems to be higher in low P level and to a lesser extent, high micro.
The Israeli avocado board (50%) and the Chief Scientist of the Ministry of Agriculture have supported the research through the end of 2020. We are requesting funds for the continuation and expansion of the study. Following the first three years, we wish to maintain the experiments for minimum of two years. This will allow us to conclude the effect of the major nutrient on avocado development and production and to develop novel fertilization management for modern orchards.
