Time to end the false debate of organic vs. mineral fertilizer

A farmer applies fertilizer on maize crop in Kenya. Should farmers use organic or mineral fertilizer? Photo by: B. Das / CIMMYT / CC BY-NC-SA

In sub-Saharan Africa, the argument has raged for quite some time now: Should farmers be using organic inputs or mineral fertilizer to stimulate crop growth? We know the region is hungry and that fertilizer in some form is essential. But which is best for people and the planet?

Despite passionate support on both sides, no consensus has been reached. This is because it is, in fact, a false debate. We shouldn’t be pitting these approaches against each other; we need to embrace both in order to meet the colossal demand for food the continent’s growing population requires. Instead, we should be questioning: How can smallholder farmers get access to both these inputs and use them in the most profitable ways?

1. Organic and mineral fertilizers have different compositions and functions, and farmers need both. While mineral fertilizers provide high amounts of nutrients that plants need in order to grow strong, organic resources contain organic carbon, which is an essential ingredient of healthy soil. Neither mineral nor organic inputs can provide both of these properties on their own. Moreover, applying these in combination often creates added benefits. For instance, in drought situations, applying crop residues in combination with fertilizer can alleviate moisture stress and enable crops to take up the nutrients in found in mineral fertilizers more easily.

2. Farmers can’t produce enough organic matter without mineral fertilizer. Rapidly expanding populations mean soils are not getting a break. Traditionally, fields would be left fallow to improve soil fertility, but now there is less opportunity to do this, and less organic matter around to apply to soils to help them regenerate. Using mineral fertilizers will actually help a farmer produce more leftover crop residue and biomass, which can be used as organic fertilizer. It has been acknowledged that mineral fertilizers are responsible for around 50 percent of the food grown in the world today, and were a key part of the Green Revolution of the 70s and 80s that saved millions from starvation. We cannot deprive farming communities of this vital resource.

3. Organic farming relies on mineral inputs too. We may not all have the whole picture on exactly what “organic” farming means. Take the example of phosphorus. This element has no biological equivalent, unlike nitrogen, which can be fixed to soil biologically by leguminous plants like soybean. Plants need phosphorus to grow, so organic farmers will use naturally occurring rock phosphate, which is chemically almost identical to some man-made phosphorus fertilizers such as triple superphosphate. In fact, some rock phosphates contain a relatively large amount of heavy metals, which are usually removed during the fertilizer production process for phosphate.

Even legumes that naturally fix nitrogen to the soil and are therefore hailed as a “green” technology cannot carry out this natural function without being fed with phosphorus.

So if this debate has been exposed as false, we need to focus instead of how we can ensure that smallholder farmers have: access to the right type of fertilizer; the knowledge on how to use them in the most efficient and profitable ways, without leaving unacceptable environmental footprints; and the knowledge on how best to integrate organic resources in combination with fertilizer.

The answer to this question has several dimensions. The “right type” refers to the need for having fertilizers that are aligned to crop needs and soil fertility conditions. For example, cassava requires relatively more potassium than nitrogen and phosphorus while for maize, the reverse is true. In Nigeria, for instance, the fertilizer industry is actively engaged in developing crop- and site-specific fertilizer blends that will address this issue.

“Knowledge” refers to the need for farmers to understand the right amount, place and time for applying fertilizer, as affected by the availability of organic inputs and cropping system characteristics. Using the example of Nigeria once again, the Agricultural Transformation Agenda invests in training agro-dealers, who can not only provide the right inputs to farmers, but also offer them advice on how to use it.

“Profitable” refers to farmers having access to these agro-inputs at an affordable cost, as well as access to the financial means to enable initial investments in agricultural intensification, perhaps in the form of smart fertilizer subsidies that the Nigerian government is making available to millions of farmers.

Thanks to public-private partnerships in Nigeria that are connecting all the parts of this puzzle as detailed above, farmers in the savannahs are growing maize after soybean, using soybean residues as organic inputs, recycling manure and targeting fertilizer to the following maize crop.

This is a very promising way to promote smallholders from subsistence to income-generating farmers, without ever having to decide between organic and mineral fertilizers.

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About the author

  • Vanlauwe

    Bernard Vanlauwe

    Bernard Vanlauwe joined the International Institute for Tropical Agriculture in Kenya in March 2012 to lead the Central Africa hub and the natural resource management research area.