I am writing to make some additional comments to the recent article by Dave Hodge on intensive cropping. I very much favour the concept of intensive cropping and would like to suggest there may be numerous advantages of using crops other than the 'main' orchard crop for the additional plantings.

I would like people to consider the selection of other 'companion' plants to suit the desired requirements for planting within or between orchard rows. Shrubs or small trees (Grumichama, Acerola, Brazilian Cherry, etc.) planted within the rows will eventually be under the canopy and produce additional crop. Palms will tower above the canopy and their slender trunks will not impede other trees or orchard management. Easily propagated and/or early-producing crops (Tamarillo, Coffee, Papaya, Banana, Mango, etc.) can give an early return while the main orchard is still in the establishment phase.

Another benefit is the increase in biodiversity with the associated reduction in pests and diseases. Northern N.S.W. banana growers have learnt the value of the Banana/Avocado relationship; the removal of the water-pumping banana leaving the avocado susceptible to phytophthora.

Legumes have long been employed in traditional plantings. Inga being used in coffee plantations to provide both shade and nitrogen. I think it was Popenoe who suggested planting pigeon pea around the mangos. Honey locust and other cool climate legumes are used as a 'nurse crop' around Walnuts in Victoria. Deciduous trees (Albizzia lebbek, Paulownia, etc.) draw minerals from the sub-soil with their roots, and conveniently drop them in their leaves as a surface mulch in the winter. They also allow maximum sunlight, and therefore warmth, in the winter, while contributing to a shaded, humid environment in the summer. Increased humidity during flowering has been shown to increase fruit set in plants of the Annona family. The standard 8x8 metre grid is an alien environment for tropical and subtropical fruits, the majority of which have evolved in a rainforest type environment.

Interplantings of native flowering and fruiting trees (Eugenia, Banksia, Grevillea, etc.) will encourage birds, with an expected reduction in the insect population. Maybe perimeter plantings of traditional native animal food trees (Native Tamarind, Red Bopple Nut, Figs, etc.) might encourage the fruit bats, parrots and cockatoos to leave our fruit alone. This may be just wishful thinking, but I have been assured by people who know about these things that 'native pests' really do prefer bush tucker to the introduced fruits.

I agree with Dave Hodge that tropical fruits will benefit from some more innovative thinking, and the best thing anyone can do is to get out in their orchard and consider some alternatives.

Phil Thomas,
Upper Dungay, Murwillumbah, N.S.W. 2484

DATE: November 1991

* * * * * * * * * * * * *