On Christmas Island this month, I had the pleasure of a tour of the MINTOPE Project. The Mine to Plant Enterprises Project (MINTOPE) is a partnership between Murdoch University, Christmas Island Phosphates and the Commonwealth.
"Establishing the scientific basis for introduction of agriculture and plant economies onto Christmas Island, on expired mining leases"
Christmas Island's economy has been heavily reliant on mining since settlement in the late 1800s. As mining on the island winds down, the community has been looking to sustainable enterprises which can replace mining in the economy. Two of the main industies under consideration are tourism and horticulture. Nearly all fresh food is imported to Christmas Island so the islanders are dependant on sometimes unreliable freight services. MINTOPE is considering a range of options for fruit, vegetable, grain and seed crops. Some of the crops trialled (top) include sorghum, millet and maize for livestock feed, legumes to improve soil fertillity as well as for human and animal consumption, tropical fruits and superfoods such as chia and quinoa.
Horticulture on Christmas Island faces a number of hurdles, including low soil nitrogen, potassium, boron and sulfur, compaction, heavy rainfall which can wash away cultivated soils and insect damage. MINTOPE has been looking at the necessary rates of fertiliser application for different cultivars and physical cultivation methods to produce successful crops. Mintope has also been trialling the growth of native hardwood tree species for timber production (bottom right). The saplings are planted in rows with a legume crop between them to reduce erosion, weeds and improve the soil.
One of the most adaptable crops trialled to date is peanuts (bottom left) which tolerate a variety of soil conditions and are also a legume so they improve the soil for future crops. Maize grown on Christmas Island has also proven successful, with the fastest growth rates in the world.
So far the project has demonstrated that with deep contour ripping to reduce compaction and erosion, and the application of small amounts of nitrogen, potassium, boron and sulphur, most sub-tropical crops can be successfully grown on Christmas Island. In many cases, two harvests are possible per year using short season cultivars. Weeds are smothered completely by legume crops so no weed control is neccessary in crops such as lablab and mung bean.
The latest report on MINTOPE's findings is available from the The Centre for Rhizobium Studies web page.