Spraying pesticides over vegetables.

Scientists warn there must be a balance between increasing access to fertilisers and preventing overuse.
Photo: Shutterstock/Franco Lucato

Finding a balance between access to fertiliser and its overuse

Farmers in poor countries struggle to afford fertilisers, leading to low yields. Better policies and subsidy programmes could bring down prices and facilitate access. At the same time researchers warn that governments must limit the environmental impact of fertiliser overuse.

Subsidies for manufacturing companies could help improve access to fertiliser in developing countries without increasing environmental stress, a team of international researchers has proposed.

In an article reviewing scientific evidence, the team presented a strategy to manage global fertiliser use while minimising nitrogen pollution — a common side effect. They note that it will be essential to increase access to fertilisers in developing countries in order to provide more food for a growing population.

The researchers highlight intergovernmental cooperation and incentives for companies to provide cheap, high-quality fertilisers as essential measures to tackle poor soils and food shortages.

Benjamin Houlton, lead author of the article and director of the University of California’s John Muir Institute of the Environment, in Davis/USA, said: “In many developing economies, lack of access to commercial fertilisers has resulted in less-than-optimal yields, and highly depleted soils which lack nutrient capital. Restoring soil nutrients with sustainable fertiliser practices is critical to promoting food security and the manifold benefits that this has for society.”

How can we solve the nitrogen challenge?

The researchers also explore the problem of negative effects of chemical fertilisers on the environment. Fertilisers can be washed off the soil by rain and run into rivers, where they can pollute drinking water and upset the ecosystem, the researchers warn. In addition, powdered nitrogen fertiliser can be carried by wind and cause aerial pollution, with health consequences for nearby communities.

Therefore, the researchers say, improving access to chemical fertilisers in developing countries must go along with appropriate education, community work and consideration for local culture and farming practices.

However, according to Houlton, affordability remains the biggest barrier for farmers in poorer nations. He advocates policies, such as offering subsidies that encourage companies to invest in developing cheap products.

“This can spur innovation and grow jobs and business opportunities,” he told SciDev.Net. “Subsidies with phase-out provisions can help launch environmental careers and inspire adoption of the most efficient agricultural technologies, with a key emphasis on efficient fertiliser technologies.”

According to the UN’s Food and Agriculture Organization (FAO), the combined global use of nitrogen, phosphorus and potassium fertilisers reached 186.7 million tonnes in 2016. However, demand in Africa was only around 3.6 million tonnes in the same year.

On the other hand, some regions in Asia — in particular India and China — suffered from chemical fertiliser overuse in 2015 due to their farmers’ reliance on monocultures such as rice, according to the study.

The researchers admit that a balance needs to be struck between increasing access to fertilisers and preventing overuse. Chemical fertiliser pollution can be reduced by micro-application, where small amounts are placed closely to each plant, and by using organic fertilisers such as farm waste products wherever possible.

The study was published in Earth’s Future, in July.

(wi)

Reference:

Benjamin Z. Houlton et al. (2019). A World of Cobenefits: Solving the Global Nitrogen Challenge. Earth's Future. https://doi.org/10.1029/2019EF001222