By Khalid Patel
Engineering News Online
International agribusiness firm Monsanto has completed construction of the largest maize-seed processing plant on the African continent, which has been in full production since January 2006.
The plant, named Thobontle, which is Tswana for ‘good harvest’, is capable of stripping 250 t of maize cobs per day and produces 750 t of seed maize every four days.
The plant makes it possible for seed-maize producers to harvest crops six weeks earlier when the grains’ moisture content is between 30% and 35%, eliminating the risk of serious damage that may result from pests during the six weeks the crop is left to be dried by the sun, explains Monsanto MD Kobus Lindeque at the official opening of the plant.
The seed dryer used to accomplish this was completed in 2000 and based on global best practices, with a view to improved seed quality.
“The seed dryer is a double-pass model with pressure and tempera-ture control. As seeds are living organisms, a reliable interlock system is used to manage the air temperature, ensuring that the seed will dry at a maximum temperature of 40 ºC within four days,” adds Monsanto seed operations manager Joel de Aquino. Located in Lichetenburg, the plant is equipped with the most advanced technology available.
The maize-seed processing faci-lity is complete with processors for bulk storage, cleaning, sizing, length graders, a gravity table, colour sorter and both treatment and packaging systems.
“A special mechanised harvester, imported from Argentinia, is used for gathering the cobs,” adds Lindeque.
Maize cobs have to be delivered to the plant within seven hours of harvesting, where the grain is then dried to a moisture content of 12 %.
The cob is then stripped of stalks and leaves, which are used as stockfeed.
Another distinct feature of the plant’s advanced equipment is the addition of a seed-grader capable of sorting the differing lengths and sizes of seeds into uniform grades, specifically formulated to facilitate the planting of the grain. “The ultramodern equipment installed in the plant allows for the gentle handling of the seed to ensure a high-quality product for farmers,” explains Aquino.
In addition, the self-cleaning design of the plant will allow for easy changes between seed batches of biotech or conventional cultivars to ensure zero contamination.
The purpose of the plant is to enhance seed quality and to improve growth vigour and the lifespan of seeds, ensuring that each seed will germinate optimally and return higher yields. The plant is situated at Lichten-burg and receives maize from different farmers spread out in dif- ferent areas, cultivating 5 000 ha of maize seed, genetically-modified and standard seed. The Lictenburg plant provides full-time employment for 70 people.
The project followed South Africa’s requirements regarding safety, health and the environment as well as global best practices in seed processing. Monsanto exports 2 000 t of maize seed annually to Southeast Asia.