Post #2330545

Whilst alluvial floodplains are not ideal for permanent structures (for obvious reasons) they can make for amazing arable land. The Canterbury Plains in New Zealand are a prime example with its productive alluvial soils (though agriculture is highly dependant on irrigation) and is the dominant arable region in New Zealand, producing the majority of its grain and seed crops and supporting a significant dairy industry. The *most* fertile land in the country, however, is generally found in the Waikato and South Auckland. It's granular soils were built from strongly weathered volcanic tephra deposits, that largely originated from the Taupo Volcanic Zone. If you're wondering if there's a connection between NZ's tephra-derived soils and the dairy industry in NSW around Tilba Tilba and the aforementioned Gulaga: No, way too old. After 65 million years since the volcano where Gulaga now stands erupted, that process is essentially spent and whatever was there has long since leached away. Plus that volcano was a shoshonite-association complex including syenite and not the kind of basaltic or andesitic material that tends to weather into the most nutrient-rich soils. #geology #agriculture #NZ #NSW