By Prof Sheunesu Mpepereki and Eng Raymond Nazare
IN our previous instalment, we discussed the need to find ways to limit production component costs such as seed fertiliser, herbicides and mechanisation as a strategy to increase enterprise profitability.
In this episode, we explore some of the strategies that can be used to bring down the costs for smallholder soya bean production in order to increase profitability.
We do that by looking at the required inputs and costs for one hectare of land.
We also introduce mechanisation options designed, developed and operationalised by agricultural engineers and scientists at the University of Zimbabwe with the aim of lowering soya bean production costs.
Our hope is that as the country moves to establish self-sufficiency through local soya bean production, efficient and appropriate home-grown models are available off the shelf for farmers to adopt.
First we look at the issue of soya bean seed, arguably the most limiting factor for soya bean production.
A wide range of varieties are available on the market, most of which yield best under high levels of management.
Medium season varieties are suitable for most soya bean growing areas and are recommended for smallholder production.
Future breeding programmes must focus on developing varieties that have a wider agro-ecological range not only to allow production in not-so-wet areas, but to guard against the vagaries of climate change.
Seed is planted at a rate of 100 kg/ha.
At current prices, the seed will cost just under US$170 for 4 x 25 kg pockets.
Many farmers plant part of their fields with seed retained from the previous harvest as a strategy to bring down production costs.
The major drawback in the use of retained seed is the issue of seed-borne diseases. Farmers are strongly encouraged to plant certified seed to ensure optimum yields.
The next key input is rhizobium inoculant.
This is a bacterial preparation that is suspended in a litre of water and mixed with seed immediately before planting.
A sachet weighing 80 grammes is sufficient for 100 kg of seed to plant on one hectare.
The bacteria form nodules on the roots of the soya bean plants inside which they literally ‘manufacture’ top dressing nitrogen fertiliser for the crop.
Each sachet costs US$5, but supplies the equivalent of
4 x 50kg ammonium nitrate fertiliser that would cost the farmer US$120/ha.
The use of inoculants represents a huge saving on fertiliser costs.
For crop establishment, the University of Zimbabwe has developed a no-till planting system with a 2-wheel tractor and a 2-row precision planter.
This machine facilitates timely planting without ploughing. Ploughing is blamed for destroying soil structure and a new double density basal fertiliser dubbed ‘Double D Fert’ is now available on the market to address this.
It is applied at the rate of 2 x 50 kg/ha.
The cost for two 50kg bags is US$80 compared to US$120 to US$140 for 4 x 50 kg bags of the regular less concentrated ‘Compound D’.
The ‘Double D Fert’ contains twice the concentration of nitrogen (N), phosphorus (P) and potassium (K), the essential nutrients required for a good soya bean yield.
The cost of the inputs and mechanisation come to US$160 per ha.
This represents a significant saving on fertiliser costs.
The use of no-till precision planters allows for timely operations to take advantage of available moisture, with correct placement of seed and fertiliser to ensure germination and establishment of optimum plant populations.
Even more importantly, we have demonstrated that fuel use per hectare can be reduced from as much as 30l/ha to as little as 5l/ha through the use of no-till planters motorised by small petrol and diesel engines rated from as low as 12HP up to 30HP.
The reduction in the carbon footprint is not only good for the farmer’s pocket through reduced fuel costs, but also for the environment which then receives less global-warming carbon dioxide, among other pollutants.
In terms of crop maintenance, pre-plant herbicide such as glyphosate and pre-plant grass and broad-leaf chemicals such as alachlor (lasso) and metribuzin respectively, can be used to control weeds.
This enables relatively large areas to be planted and managed effectively to produce high yields.
This is particularly important given the significant reduction in available labour as many former farm workers now till their own pieces of land or engage in gold-panning activities following the decriminalisation of the practice.
Children who used to assist parents with agricultural chores now spend most of their time at school.
The application rates and costs of herbicides for a hectare of soya crop are as follows: glyphosate 2l/ha @US$4/l; lasso 1,5l/ha @US$10/l and metribuzin 1l/ha @US$18/l.
Application of pre-emergence herbicides is by knapsack sprayer.
The cost of herbicides and mechanisation for this stage is estimated at only US$35/ha.
Post emergence herbicides will include fusilade/agil for grasses @1 l/ha and chloromuron (classic) for controlling broad leaf weeds @ 1 x 35g sachet/ha, all applied by knapsack sprayer.
The estimated cost for post-emergence crop maintenance comes to US$35 (chemical US$30; mechanisation US$5).
Application of post-emergence herbicides is by knapsack sprayer.
The cost of herbicides and mechanisation is estimated at only US$35/ha.
The next critical step in the soya bean production cycle is harvesting.
Two options are available.
Where labour is readily available, hand harvesting can be used.
Alternatively, small-scale shelling machines can be deployed in place of combine harvesters which are not appropriate for small-scale operations.
Several versions of threshing machines have been developed and deployed in some of the country’s soya bean-producing areas.
More research and development is required in this area as crop losses during harvesting will discourage many farmers from taking up or producing soya bean at scale.
The use of mechanised threshers allows for rapid harvesting before shattering losses become significant.
There is still a labour requirement, but much less than pure hand-harvesting.
Harvesting costs are estimated at US$100/ha.
Overall, these harvesting options bring in more of the crop compared to use of combine harvesters on large scale farms where as much as 30 percent of the crop is not recovered.
The soya bean production model we have outlined costs an estimated US$505 per hectare as total input.
Assuming a yield of 2,5 ton/ha and a producer price of US$500/ton, a margin of US$745/ha is possible.
If the crop has been well maintained, yields of up to 3ton/ha are possible and the profit margins become even more attractive.
We have illustrated that soya bean production models can be developed that allow profitable production.
Mechanisation options have been developed at the University of Zimbabwe and have been tested. Local industry needs to be roped in for further research and development, optimisation and large scale manufacture of these mechanisation units that service the small-to-medium scale farmers.
With mechanisation will come scaling up and that will translate to economies of scale for farmers.
Farmers will need appropriate financial, technical and advisory support to mainstream these production models.
Government policy support will be critical to ensure that appropriate mechanisation models are developed in collaboration with local industries in order to scale up production and create surpluses for value-addition and export to earn foreign currency for the economy.