Why is there so much produce along the Great Taste Trail?
Vegetable crops, apple orchards, vineyards, hop farms and pasture, all feature along the Great Taste Trail. So why is the region blessed with such abundance and diversity?
Much of the answer lies beneath your bike tyres. As well as climate, Tasman’s topography and soil types give areas in the valleys and plains ideal growing conditions for different crops.
The most productive land is located on the Waimea Plains and the flats around Motueka. For the past 12,000 years, the surrounding rivers served as conveyor belts and supplied fresh sediment upon which soil could form.
So called Recent Soils on the river flats and lower terraces are young, crumbly, and comprise a natural fertility. Rainwater has not yet had enough time to leach nutrients out of the soil profile. Favoured by a suitable climate and flat topography, Recent Soils support the growth of a wide range of crops.
In places where the soil is not so well drained, such as in the Moutere Valley, waterlogging might occur. Scientists call these soils Gley Soils.
Gley soils are where wetlands would naturally occur. However once drained, a Gley Soil can be used for growing food, such as Braeburn apple.
Soils that have been drained for prolonged periods of time might transform into a Brown Soil. This results from the oxidation of iron and the weathering of clay minerals. Brown Soils are mature soils and the most common soil type in New Zealand.
Stony variants of Brown Soils are found south-west of Richmond, where infiltrating water percolates relatively freely through the soil profile.
The advantage of using well-drained soils for agricultural production on flat land made some growers decide to relocate their orchards from the Moutere Gravels to the plains.
The Moutere Gravels are a sedimentary layer of clay-bound gravels that formed as outwash from the rising Southern Alps and may be as deep as 1000 m in places. The soils that developed in Moutere Gravels are old, Ultic Soils. They are survivors who did not rejuvenate during the last cold phases of glaciation.
Due to their age, Ultic Soils are nutrient poorer and clay-enriched in the subsoil. As clay minerals can shrink and swell with fluctuating soil moisture levels, Ultic Soils tend to be difficult to work. In winter they are wet, and in summer they can become hard.
Three percent of all soils in New Zealand fall into the Ultic category and only the ones around Moutere and Māpua grow high-quality apples.
Overall, about 50,000 ha (~6%) of the total land area in the Tasman District is deemed suitable for intensive agricultural production. Productive land is a crucial and limited resource, under pressure from suburbanisation and land fragmentation.
- Thanks to Dr Anne Wecking, Soil Scientist at Tasman District Council for kindly assisting with this content
