Getting the Most Out of Fertilizer
This blog is adapted from the International Fertilizer Development Center’s (IFDC) paper, “Fertilizer and Soil Health in Africa: The Role of Fertilizer in Building Soil Health to Sustain Farming and Address Climate Change.”
In agriculture, soil degradation is primarily driven by poor fertilizer application and suboptimal management of nutrients, which leads to nutrient losses and a decline in soil’s biological, chemical and physical quality. This reduces its capacity to support agricultural production and environmental functions. Soil degradation is a major issue affecting crop productivity and the prevalence of malnutrition in sub-Saharan Africa (SSA). The subcontinent loses over $4 billion worth of soil nutrients each year. It remains the only area in the world to experience negative nutrient balances, which continue to worsen yearly and have stagnated the region’s ability to produce nutritious food.
Mineral fertilizers play an essential role in raising crop yields. They replace the nutrients that plants mine from the soil as they grow. When farmers use an appropriate amount of the right kind of fertilizer, in tandem with proper management practices, for their crops and soils, they can grow more food on less land. This increase in yields allows farmers to grow enough food without expanding into uncultivated areas, halting and potentially reversing deforestation and conserving biodiversity.
Incorrect use of fertilizer leads to poor use efficiency and nutrient uptake. The underlying reasons for poor fertilizer use efficiency are complex, but include: (1) suboptimal crop management in terms of sowing time, crop density, timely weeding, etc.; (2) late application of fertilizer, often caused by issues with timely access to inputs; (3) an inappropriate fertilizer formulation for the local conditions, which causes over- or underapplication of nutrients; (4) lack of training in soil fertility management; and (5) poor soil health.
To successfully address soil degradation in SSA, we must improve nutrient use efficiencies. At current fertilizer application rates in the region, soils continue to lose nutrients faster than they are replaced, which leads to substantial soil degradation and declining soil health — and left unchecked, this will eventually result in nonresponsive soils.
Food security can only be achieved in healthy, fertile and productive soils. Therefore, agricultural intensification in SSA should be supported by science-based agronomic approaches to improve soil fertility at scale, enhance the affordability and availability of fertilizers, offer targeted fertilizer recommendations tailored to localized variations in soil fertility and the environment, and provide incentives for farmers to invest in their soils.
Making the most with the least fertilizer
The social, economic and environmental sustainability outcomes of fertilizer use in crop production systems are dictated by a delicate balance of needs: increasing productivity, optimizing economic returns, minimizing adverse environmental effects and maintaining soil health and ecosystem services. Judicious fertilizer use is crucial to fertilizer’s success. This means that fertilizer application must be tailored to conditions specific to each location to increase yields, profitability and nutrient use efficiency. Agricultural intensification in SSA should be supported by science-based agronomic approaches to improve soil fertility at scale, enhance the affordability and availability of fertilizers, spatially target fertilizer recommendations and provide incentives for farmers to invest in their soils.
Several innovative approaches have been introduced to reduce the negative impacts of agriculture while increasing yields and sustainability; these approaches include transformational techniques such as the 4Rs of Nutrient Stewardship, the application of geographic information systems (GIS) data and Integrated Soil Fertility Management (ISFM).
The 4Rs of Nutrient Stewardship — right source, right rate, right time and right place — ensure that fertilizer is used appropriately and managed effectively and efficiently. Fertilizer use becomes affordable for smallholder farmers when crop yields increase significantly and fertilizer waste and runoff are minimized. According to a recent paper from IFDC, “Fertilizer and Soil Health in Africa,” yields are generally lower than expected when no fertilizer is applied, suggesting limitations associated with low soil nutrient availability in places like SSA. Even with low rainfall levels, opportunities exist to more than double crop productivity using fertilizers.
When GIS data is combined with regional and local knowledge, farmers can make informed decisions about the type and amount of fertilizer to use for their preferred crops. An ideal fertilizer recommendation allows farmers to achieve potential yields, maximize fertilizer use efficiency, and optimize economic returns while maintaining soil health over the long term. These approaches will maximize nutrient use efficiency and ensure that crop productivity increases in SSA can be achieved and sustained.
Fertilizer alone is not enough; it should be combined with other crop, soil and water management practices to improve soil health. ISFM combines the use of mineral fertilizers with organic inputs, quality seeds, improved germplasm and good agricultural practices to optimize the agronomic efficiency of fertilizer and enhance soil health and productivity. The approach balances nutrient supply and demand, enhances nutrient use efficiency and improves soil characteristics.
Overcoming barriers to efficient fertilizer use
Fertilizer use can lead to negative environmental consequences if not managed properly. For example, excessive fertilizer use can lead to soil and water pollution, greenhouse gas emissions and other environmental problems. Therefore, it is essential to use fertilizer in a way that maximizes its benefits while minimizing its negative environmental impacts.
To overcome barriers to efficient fertilizer use and encourage farmer adoption, IFDC recommends:
- Enhancing access to affordable and quality fertilizers.
- Providing extension services and agricultural advisory services that include good soil health management and agronomic practices, water management, weather-crop insurance and market information.
- Bundling fertilizer use promotion programs with soil conservation and organic matter management to provide better incentives for farmers to use fertilizer.
- Creating a favorable, enabling environment through targeted policy interventions that support the delivery of broadened and digitally enabled fertilizer management recommendations and the creation of conditions that allow smallholder farmers to implement these recommendations at scale.
- Redesigning fertilizer subsidies to make them smarter with respect to soil health management.
- Facilitating access to data and analytics to monitor the status of and changes in soil health and collecting and analyzing medium- to long-term data on the impact of farmer practices on soil health properties.
- Providing policymakers with reliable estimates of soil health benefits on environmental outcomes and ecosystem services, including the benefits of land spared from agriculture through sustainable intensification.
By implementing these measures, farmers can be encouraged to adopt fertilizer and other soil health management practices, leading to improved soil health, increased crop productivity and enhanced food security. With judicious fertilizer use, enhancements in soil health, crop productivity and food security benefit not only farmers, but people across the globe. By increasing the nutritional capacity of our soils with fertilizer, we can ensure that nutritious, healthy food reaches individuals around the world.