Thursday Island Community Horticulture
Since 2011, a horticultural program initiated by former schoolteacher and educator George Ernst uses improved agronomic practices to help soil fertility replenishment and the growing of nutritious food on the poor soils of Thursday Island in Queensland, Australia.
The problem
The Torres Strait Islands, which lie between mainland Australia and Papua New Guinea, have the highest diabetes rates in Australia. Many residents, who are mostly of Aboriginal and Torres Strait Islander extraction, have diets high in simple carbohydrates and fats and low in vegetables and fruit, and many do not get enough exercise. This has led to high rates of hypertension, obesity, heart disease, diabetes and various cancers. Food gardens are scarce in the southern Torres Strait due to loss of traditional knowledge, infertile soils, a long dry season and the ease of purchasing food from stores.
Agrobiodiversity
As part of the Thursday Island Community Horticultural Program , circular demonstration plots are established in prominent positions on public land. Species to be grown are selected in consultation with local communities and include local tropical and sub-tropical species along with introduced temperate trees and herbs. These include: taro, sweetpotato, lemon grass, chilli, papaya, mango, lemon, pineapple, watermelon, aibika ( Abelmoschus manihot ), pumpkin, cassava, basil, noni ( Morinda citrifolia ), curly-leaf spinach and sweetleaf ( Sauropus androgynus ). Plots are dug (the soil on Thursday Island is hard and relatively unfertile), then organic/inorganic fertilizers are applied and irrigation connected if required. Each mound/plot is around 3.5 meters in diameter and typically contains a central fruit tree -such as a grafted lemon or mango or a papaya- surrounded by several shrubs and/or a prostrate species such as pumpkin that are complementary space-occupiers and bear fruit in a much shorter time. Mulch (in the form of wood chips from fallen trees provided by the Council) is essential as it lowers soil water loss and temperature during the dry season and gradually breaks down to provide compost for the plants and soil microbes. In a relatively short time the soil in these plots becomes rich, well aerated and high in organic matter, providing greater nutrient content to the plants that grow there (see Table 1).
Table 1. Comparison of select mineral nutrient concentrations in leaves of two crops grown on unimproved soil and improved demonstration plots on Thursday island. Note: sweetpotato and papaya yields were approximately 2.5 times higher on the improved plots.
Crop | Soil | Nutrient (% dry wt) | ||||||
|---|---|---|---|---|---|---|---|---|
|
| Zn | Ca | Mg | K | P | S | N |
Sweetpotato | Unimproved soils | 0.0018 | 0.65 | 0.29 | 2.1 | 0.29 | 0.24 | 3.2 |
| Demonstration plots | 0.0063 | 1.29 | 0.42 | 3.3 | 0.35 | 0.32 | 3.8 |
Papaya | Unimproved soils | 0.0021 | 0.41 | 0.35 | 1.9 | 0.33 | 0.33 | 3.5 |
| Demonstration plots | 0.0035 | 1.07 | 0.56 | 3.2 | 0.49 | 0.48 | 4.6 |
The Project
Initially funded by Queensland Technical and Further Education (TAFE) with assistance from the Australian Centre for International Agricultural Research (ACIAR), and now by the Torres Shire Council, the Program has built over 60 plots and more are planned. Mostly located on road verges or unused public land, the plots enhance urban decor; they are easily accessible to the public and identified with painted pegs bearing plant names, date of planting and by whom. Additional information, including maturity for eating, may also be displayed. The program could be considered as an outback Australian version of the Incredible Edible Todmorden initiative featured in the Diversifying Food and Diets book (Case study 10).
Scaling up
As part of a larger community health program, it is difficult to determine the impact that can be attributed to the Horticulture Program alone. However, “seeing is believing” and the plots are well-known, visible, popular and fulfill an important educational role. Efforts to scale up the program will most probably gain impetus once the fitness/diet program data are published. At the local level, there have already been policy impacts. The Torres Shire Council, which has supported the horticulture program from the start, has allocated additional resources to expand the scheme to the underutilised Snake Gully (also on Thursday Island) for fruit and vegetable production.
Input by Australian ACIAR has fostered a Drumstick tree (Moringa oleifera) planting program within the horticulture program. Around 100 seedlings have been grown in a nursery and are being transplanted around the island. Unlike most of the other food plant species being grown, the Drumstick plants grow quickly and even quicker on the demonstration plots. The benefits of Drumstick leaves, which include anti-diabetes, anti-heart disease and anti-cancer effects, are being promoted as part of the program (see ACIAR factsheet 8 below).
A key lesson from both of these programs is the importance of motivated, knowledgeable leaders to ensure project success and upscaling. A challenge for the horticulture program is getting enough volunteers to manage the plots, including weeding and watering when required.