Effect of seaweed extract on avocado root growth, yield and post-harvest quality in far north Queensland, Australia

Abstract

Seaweed extracts are proven to increase productivity in many agricultural crops, but there is limited research on their use in avocado production. Therefore, we evaluated the effectiveness of a seaweed extract from Durvillaea potatorum and Ascophyllum nodosum on avocado yield, revenue and post-harvest fruit quality in a series of field experiments in Australia, and on seedling root growth in a pot experiment. The field experiments were conducted on commercial farms across three different locations in northern Queensland over four years and utilised avocado trees with different ages, cultivars (Hass and Shepard) and inoculum pressures from Phytophthora cinnamomi. Results showed that the application of the seaweed extract by fertigation significantly improved avocado yield (kg fruit per tree) by 38%, fruit firmness by 4% (skin) and 22% (flesh) and fruit skin colour by 1° (hue), and an upgraded visual ripeness score. The increases in yield were associated with greater number of fruits per tree (up to 42%) indicating the liquid seaweed extract improved fruit set and retention per tree. Regular soil application of the seaweed extract to young trees (cv. Hass) in pots increased the root fresh weight by 22%. Overall, the regular application of the seaweed extract to avocado trees was found to be practical and economically viable for improving fruit production and post-harvest quality in Australian orchards.

Influence of Spraying Some Biostimulants on Yield, Fruit Quality, Oil Fruit Content and Nutritional Status of Olive (Olea europaea L.) under Salinity

“…cvs. Hass and Shepard [101]. It was reported by many authors that spraying SWE was more effective in enhancing vegetative growth, yield, fruit chemical and physical characteristics and the nutritional status of grapes when compared to untreated trees [102][103][104].…”

The growth effect of drench treatments of a seaweed biostimulant made from Ecklonia maxima on transplanted Hass (c.v.) avocado clones within the propagation phase

“…), with the 1.5% Afrikelp™ treatment (32.5%) giving the greatest increase of 18.5% compared to the control (27.46%). As stated above, it is likely that these increases would become signi cant, if treatments were continued for the remainder of the hardening off period as experienced within commercial avocado nurseries, and as observed by Arioli et al (2023).…”

“…Limited research, however, has been conducted on the effects of seaweed extracts on avocado plants, especially within the propagation stage. A recent study by Arioli et al (2023) on containerised young avocado (c.v. Hass) plants, reported a 22% increase in fresh root weight from frequent soil drenches with a seaweed extract.…”

The growth effect of a seaweed extract made from Ecklonia maxima on germinating Avocado and Pecan seed

“…Thus, optimizing the timing and concentration of SWE biostimulants is elementary to realizing the potential of SWE. (Arioli et al, 2023). Both avocado and pecan industries rely on seed as the primary source for the grafting propagation methods that are later applied.…”