Microdosing: Cutting waste and putting nutrients exactly where they are needed

For many smallholder farmers, the cost of purchasing fertilizers to nourish their crops is a necessary but often exorbitant part of their cost of production. Often, it is part of the main costs that determine if the farmer makes a profit or loss on production at the end of the harvest season.

And due to an awareness of this fact, many African governments - including Nigeria - are now subsidizing the cost of fertilizer purchase for their farmers to drive down their input cost, their entire cost of production and as a result help make their produce more competitive and gain better market access through reduced selling price.

Despite this expensive cost of fertilizer and its effect on the competitiveness and market access of farmers, the conventional mode of fertilizer application by many farmers - including smallholders - calls into question the efficiency of the use of this expensive resource. Many farmers usually practice the age-long broadcasting/heavy application with little thought for use-efficiency and often with the erroneous belief that the higher the dosage the better the yield.

This is not only economically inefficient but it is also damaging to the health of the soil and ecologically unsustainable. Also, over the years, this indiscriminate and uncontrolled application can lead to soil acidification and salinization. These can significantly reduce the productive capacity of the soil and may require heavy investment in corrective measures or, for smallholder farmers, lead to the abandoning of farmlands and deforestation or the opening up of new agricultural lands - another act which is unsustainable in the long term.

Besides, the indiscriminate use of fertilizer also impacts other natural resource sectors like fishery negatively. The excess nutrients in the soil are leached out during the rains and are washed downstream into groundwater and surface water bodies causing eutrophication - a process whereby waters in lakes/streams become abnormally enriched with nutrients.

This excessive enrichment causes an explosion in the population of algae and other microorganisms in the water and subsequently leads to the depletion of oxygen available to the fish and other water organisms. This reduced oxygen, in turn, may lead to suffocation and death of many aquatic organisms and negatively impact local fisheries and those whose livelihoods depend on them.

This is why microdosing is a more sustainable approach to fertilizer usage. It is a usage approach that strives to cut waste and put fertilizer exactly where it is needed. According to an article posted on theFarming First magazine website in January 2011, "microdosing involves the application of small, affordable quantities of fertilizer onto the seed at planting time, or a few weeks after emergence".

It is a method particularly suited to smallholder farmers with small piece of farmlands. Because the fertilizer is applied at the base of each crop plant, microdosing can also help in weed management by starving weeds seeds of this growth resource and helping crops to out-compete weeds through the stimulation of a faster growth rate and canopy formation of crops which shuts out other vital resources like light from weed seeds. This method leads to a reduction in the cost of weeding and herbicidal control.

In all, the technique enhances the efficiency of fertilizer use and result in improved productivity. In economic terms, it reduces the cost of production of smallholder farmers and at the same time increases their output through better and more efficient resource use. That, in my view, is a right combination for wealth creation for smallholders.

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Bunmi Ajilore: First and foremost an agriculturist; environmental biologist and ecotoxicologist. Advocate of sustainable agriculture, climate change adaptation and mitigation, food security, environment, and youth involvement/participation in shaping and implementing the policies influencing these issues.