Edgar Vhera
Agriculture Specialist Writer
SUGAR bean farmers can save more than US$100 per hectare by using rhizobium bio-fertiliser instead of chemical fertilisers, the Government has advised, as planting of the legume reaches fever pitch.
The Ministry of Lands, Agriculture, Fisheries, Water and Rural Development issued the piece of advice to prospective sugar bean growers this year, as the country targets to increase its hectarage from 34 488 hectares in the 2023/24 season to 55 000 this term.
The Crops, Horticulture, Fisheries and Livestock Summer Plan: 2024/2025 (CLAFA-2) also seeks to increase the crop’s average yield from one tonne per hectare to 1, 1 and total production from 15 042 tonnes to 60 500.
In a recent X (formerly Twitter) post, the Ministry said this was the prime time for sugar bean planting and recommended the use of rhizobium to inoculate the seed and reduce costs on mineral nitrogen fertilisers.
“Through the biological nitrogen fixation process, rhizobia fix enough nitrogen for the crop’s requirements. It is cheaper than mineral nitrogen fertiliser for the production of the crop,” read the notice.
It added that sugar beans required 40 to 60 kilogrammes of nitrogen per hectare, while rhizobium bacteria fix 50 to 60 kilogrammes for each hectare.
Using ammonium nitrate (AN) would require between 150 and 200 kg per hectare. At current market prices, this will cost between US$120 and US$160 per hectare.
Using rhizobium fertiliser costs only US$48 per hectare, allowing the farmer to save between US$72 and US$112. A sachet of rhizobia costs US$12 and four are required per hectare.
The Ministry also advised farmers on how to inoculate, precautions, benefits and where to buy the inoculant.
“Farmers can purchase the inoculant from the Department of Research and Specialist Services (DRSS) head office, Chemistry and Soil Research Institute, Soil Productivity Research Laboratory, Grasslands Research Station, Marondera, as well as provincial and district Agritex offices,” said the Ministry.
Head of the Chemistry and Soil Research Institute (CRSI), Mr Emmanuel Chikwari, yesterday said they were on high alert to curb the sale of fake rhizobium sachets and urged farmers to buy from their offices or reputable agro-dealers like Farm and City, which purchase from their offices for re-sale.
In the 2022/23 season, the Institute, in collaboration with the Fertiliser, Farm Feeds and Remedies Institute (FFSRI) and police, conducted an inspection blitz and uncovered a concerning issue where some agro-dealers were selling fake rhizobium inoculant sachets for US$5. Rhizobia are invisible living organisms that are only visible in sachets.
Mr Chikwari advised farmers to continue planting sugar beans until early February, subject to the availability of rains, and to take advantage of the transition from summer to winter when temperatures begin to drop to ideal levels for crop growth.
The Ministry recently launched the rhizobia inoculant production and utilisation initiative for the 2024/25 season in Marondera and called for its use in soya and sugar bean cultivation.
An agronomist with a local seed producer, who is not authorised to speak, said sugar beans are still within their planting season.
“It is important for farmers to observe planting dates so that critical growth stages, such as flowering and grain filling, do not occur during periods of moisture stress or frost.
“Profitable sugar bean production hinges on the ability to combine seed selection with good agronomic practices (GAPs),” he said.
The agronomist encouraged farmers to perform inoculation to ensure successful nodulation.
“Inoculation is the process of introducing the appropriate rhizobium bacteria to the soil in numbers sufficient to ensure successful nodulation,” he explained.