Machinery

: 15 October 2019; Hits: 5177

Low-cost storage method that prevents cowpeas from weevils

air separator

Millions of farmers across Africa can now prevent their cowpeas from destructive weevils using a low-cost innovative way of storing the legumes.

Scientists have been studying how farmers store cowpeas and learnt that a long-standing method of killing cowpea weevils involved storing the harvest inside three-layered and individually sealed plastic bags. It was assumed the pests died of suffocation something which was not to be.

Now researchers in Africa and the US have published a study of the method saying that while lack of oxygen reduces the weevils' feeding activity, what actually kills them is lack of water, and that the drier the harvest at the time of storage the harder it is for the weevils to survive and multiply.

Harvested beans are vulnerable to cowpea weevils, Callosobruchus maculatus, which can multiply rapidly. Even a small infestation can destroy an entire stored crop in a few months.

"The weevils use oxygen to produce water and so are deprived of their main water source. But some of their water, maybe 15–20 per cent, comes from the seed," said Larry Murdock, an entomologist at US-based Purdue University and lead author of the study.

Millions of triple plastic bags have already been distributed across West and Central Africa through the Purdue Improved Cowpea Storage (PICS) bags project that targets West, Central and East Africa. "The simple recommendation is to store, in a PICS bag or via other methods, your grain when it is drier, if you can, because you're reducing the supply of water and placing the weevils under even greater water stress," Murdock said.

The team are now investigating whether the dry, airtight environment inhibits other cowpea pests in the same way.

Scientists and researchers in Kenya have welcomed the study at a time when Kenyan farmers are struggling with post-harvest losses in cowpeas. “I strongly feel that average prices can increase 60–100 percent between harvest and the next planting season. So any improvement in storage has the potential to increase revenue by that much," said Mucheke Mugene from the Tegemeo Institute of Agriculture.

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: 14 October 2019; Hits: 8324

Graduates unveil cheap, locally made solar-powered cold-room for preserving fresh farm produce

Colreftec Solutions Limited cold room

Farmers and traders dealing in perishable farm produce in Kenya can now save up to 20 per cent on cold-room purchase and Sh20, 0000 monthly electricity bills using locally fabricated solar-powered cold-rooms thanks to two graduates who have unveiled both mobile and fixed cold rooms fit for all farmers.

Peter Mutua and Peter Muhoho mechanical engineers graduates from Kenyatta University (KU) motivated by the fact that 50 per cent of harvested fresh produce in the country goes to waste between the farm and market last year April founded Colreftec Solutions Limited, a start-up company through which there are now providing cold room services to their different clients.

“What really motivated us was the increasingly perishable products resulting to huge post-harvest losses for farmers and therefore our aim is basically to prolong the shelf life of these perishables products that include fruits, vegetables and flowers among others,” said Mutua, the company’s CEO and co-founder.

From Chandaria Business Incubation Center where the idea was hatched the cold-rooms have been tried out and their performance has proven excellent especially in the Sub-Saharan region where sunlight intensity is plenty throughout the year.

How Colreftec works

The cold-rooms basically preserve the produce within the set temperature by use of digital thermostat which helps maintain a temperature of the produce put in the cold room at the range of (0-5) degrees Celsius.

The cold rooms are also fitted with standby batteries which are charged and can offer power when there is limited sunlight or at night when there is no sunlight.

“Ideally, by use of solar panel we harness the solar energy and store it in the battery. We do sizing of the solar equipment to ensure sufficient flow of energy during the day and night,” said Mutua.

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The energy stored in the battery powers the condensing unit, the security unit as well as the lighting of the bulbs during the night. This is achieved by calculating the load to be stored to help the engineers estimate the power needed to drive the entire system.

“The solar cold room can operate in regions that have minimal sunlight. We engage our clients to determine the regions where they come from to know the number of hours the region is likely to experience the sunlight and use the information to calculate the number of solar power that can harness adequate solar energy to be stored in the batteries.”

Mutual further says that with the right details they are able to determine the power needed to supply the entire system as the energy used by the cold room varies depending on the size of the cold room and the load to be stored in it.

Capacity

According to Mutua, the capacity of the facility depends on client’s specifications. For instance, a cold room of 6ft by 6ft by 7ft has the capability to store more than two tonnes of tomatoes in more than 10-15 days maintained at a temperature range of 5-6 Degrees Celsius.

This enables the client to seek a ready market where the produce can be transported and sold hence reducing risks of wastages hence farmers will not have to sell their produce at throwaway prices leading losses.

Mutua notes that in the agricultural sector in the country, solar-powered cold rooms offer quality foods and of high nutritional value as it is eco-friendly by the virtue that it is using green energy which is renewable.

Caption: Peter Mutua closing the door of one of the Colreftec cold-rooms. Photo: Zablon Oyugi.

Colreftec Solutions Limited can be reached on This email address is being protected from spambots. You need JavaScript enabled to view it. +254708801754 or +254711833599

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: 11 October 2019; Hits: 7080

Wick irrigation system saves water and time for farmers

wick irrigation system by Musa Juma

Farmers in dry areas can save the amount of water needed for their crops and time needed to manage the watering of their farms by employing wick irrigation system that cuts water usage and is automatic hence farmers do not need to open and close it at any given time.

The irrigation system which is championed by Ruben Centre, a non-profit and faith-based organization based in Nairobi, Kenya uses wicks and plastic hollow pipes of diameter from 15mm to 150mm through which water is let to flow.

“This irrigation system is very effective as we have tried it in Soma and currently we are setting it for farmers in Turkana County to help then grow different crops such as spinach, kales, okra, jute mallow, spider plant, eggplant, capsicum, cow peace, nightshade, amaranths, and watermelon in the dry area,” said Musa Juma, technician at Ruben Centre.

How the system is set

Though setting a wick irrigation system is technical which needs an expert, trained farmers can set it by themselves in their farms once the required materials are assembled.

First a farmer needs to prepare wick garden, for example, measuring 2mx4m with a capacity of 75 litres of water sustaining the garden for two weeks.

Two small cuts parallel to each other are them made depending on the thickness of the wick at some intervals depending on the crop spacing from the top on one side of the pipe.

The cuts are supposed to enable insertion of the wicks with the shorter end of about 15mm is let inside the pipe while the other longer end of the wick is left hanging.

The pipe is then properly buried inside and covered with soil completely with side holding the wicks facing upwards. The pipe should be tested whether it balances by letting some water run through it.

The longer hanging side of the wicks outside the pipes are then spread away from the pipe and covered shallowly in the soil on either side of the pipe.

Seedling is then planted on either side of the wicks with the correct spacing. This is done for all the pipes in the farm before letting water fully in them and then closed from either ends until it is completely sucked by the wicks and to the plant root for uptake.

“once a farmer does all these, he or she does not need to be in the farm to manage the irrigation as it will be automatic until the pipes are run out of the water and there is need to add more,” said Juma.

Ruben Centre offers wick irrigation training at a fee for farmers.

Caption: Musa Juma of Ruben Centre explaining how wick irrigation works. Photo: Zablon Oyugi.

Juma can be reached on +254 722 672 250 while Ruben Centre on +254 0778848801 / 0717 788 801 or Email: This email address is being protected from spambots. You need JavaScript enabled to view it.

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