The Sunday Mail
INNOVATION and technology have opened up a whole new world of possibilities in agriculture, enabling local farmers to effortlessly practise organic farming, recycle waste for productive purposes and conserve water.
The result has increased output from relatively small pieces of land. This model is helping ensure sustainable production and food security.
Many youths are jumping on the bandwagon. The Ministry of Lands, Agriculture, Fisheries, Water and Rural Development is presently spearheading this model — called integrated farming — to empower young farmers. Marlborough-based Brighton Chiwera, who co-owns Sleek Acre Farm with his wife, is optimistic about the future of integrated farming.
Chiwera, who is the farm director, is into aquaculture and apiculture (beekeeping). He also grows button mushrooms and organic vegetables.
He employs conservation farming models, which involve recycling waste and water. His project covers one acre. At the gate, one is greeted by beehives mounted on trees. Others are mounted in the veranda and one corner of the yard.
Further down is a 102 square-metre fishpond in a greenhouse. The pond bursts with breams. He produces about 4 000 breams every eight months. Chiwera replicates Kariba’s hot temperatures to stimulate production.
In winter, he uses the greenhouse to increase fish production. After every winter, when demand outstrips supply, he harvests about four tonnes of fish. He said he uses what is known as the Venturi effect to conserve energy in the fish pond. In essence, he uses a pump to suck oxygen from the atmosphere and passes it into the pond in a dissolved form for the fish.
There are 12 water recycling points in the fishpond, while a sand filter is used to trap fish waste. The waste, which is rich in nitrogen, is then used in a compost to feed the mushroom fungi. The result is production of quality button mushrooms. “Between May and August, the fish are in warm water, where they feed and grow,” he said.
“By end of August to mid-September, we will have big fish weighing close to 750 grammes, some about a kilogramme. From 4 000 fish I will have kept during eight months, I get about threeand-a-half tonnes of fish.
“Usually, just after winter, demand for fish is high, and I can sell a kilogramme for US$5.” He uses air conditioners to maintain the required temperatures in his mushroom grow house to enable him to produce all year round. Chiwera has invested in a 10kva solar system for power.
The farmer uses wheat straw and horse or chicken manure to fertilise his mushrooms. These are mixed to make a compost. Waste water from the fish pond, which is rich in nitrogen, is then used to pre-wet the compost.
After some days, the compost is loaded into crates, and placed in a peak heat room, where it is pasteurised before undergoing several other processes.
The crates are later placed uniformly in the grow house, before mushroom fungi is spread on top. Chiwera also has an orchard with various fruit trees. They include mango, apple, orange, guava, plum, nartjie, pomegranate and pear trees. The trees are fertilised using waste manure from the button mushroom section.
In the garden, he produces strawberries and a variety of vegetables. He said he rakes in up to US$100 000 annually. Conservation models Another conservation model used on the farm involves the extraction of methane gas from fermented sewerage that collects in a septic tank.
He collects an average 13,2 kilogrammes of gas monthly. “You can use this gas for cooking. This model can be used in schools which have lots of food waste that can be thrown into the septic tank to boost fermentation, which then increases volumes of the methane gas,” he said.
Through the greywater system, Chiwera collects about 1 250 litres of waste water in an underground tank for recycling every two days. The water is used for laundry, dishwashing and bathing.
The tank has a sand filter on one side that separates stuff such as oil from the water, which is further cleaned using chlorine for reuse.
“Imagine if, in our households of an average of five people, we save 1 250 litres in two days? What impact will we see if the concept was adopted by the Harare City Council and other councils?” he added.
For Chiwera, integrated farming is a combination of a well-thought-out process and willingness to research and implement new ideas.
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