Geoff’s 800 square meter pond is shaped like a soup plate with a perfectly flat 2m deep bottom, ideal for growing out fish of all types.
This particular pond was allowed to mature and develop. Consequently, it was overgrown with weeds and grass. To clean out the system, Geoff decided to drain the pond partially so he can use cows to graze right down to the water’s edge. He then moves them off a few days later, when the task is complete. A lot of people have read about soil compaction caused by over-grazing by cattle and sheep, turning the soft soil into a hard concrete pan and resulting in soil erosion and land degradation. People balk at using animals near a water system these days. But here, Geoff uses the cows and horses to quickly blitz the water’s edge before moving them away.
Shocking the system with animal nutrient and pocketing the landscape, briefly, with their aerated hoof prints, captures water in a rain event and soaks it deep into the system along with their nutrient. It’s all part of the permaculture design process. Multiple functions with a diversity of added benefits.
Geoff uses a 12-volt solar panel to power a pump hooked up to a battery to trickle water over a 250-litre blue drum filled with gravel to add a little extra aeration to the pond over the summer period. It’s not absolutely necessary, but in a heavily stocked system, it’s a wise investment to guarantee dissolved oxygen in the water. Dissolved oxygen drains off faster as the water temperature rises. The cooler the temps, the more oxygen your pond is able to support.
The other innovation was a purpose-built smaller pond, adjacent the main pond and used to optionally feed the fish and capture them with a sluice gate, ready for harvest. If that’s not enough, growing food on a bamboo raft is another innovation Geoff designed that also acts as a floating small fish refuge system. Then there are the solar panel lights on the raft to attract insects at night to act as a source of extra fish food.
Now you know why Geoff Lawton heads the Permaculture Research Institute. All this stuff gets tested on his farm to see what works and what doesn’t.
Watch the video below to get all the details.