How much nitrogen does Africa need to feed itself by 2050?

Area of Science:

• Agricultural Science
• Environmental Science
• Food Security

Background:

• Nitrogen (N) fertilizers are crucial for global food self-sufficiency (FSS), especially in Africa where agricultural N input is low.
• This study is the first to calculate the specific N fertilizer needs for each African country to achieve FSS by 2050.

Purpose of the Study:

• To calculate the required inorganic fertilizer N (IFN) for African FSS by 2050 under various dietary and fertilization scenarios.
• To analyze the impact of these scenarios on N budget, N losses, and N use efficiency (NUE).

Main Methods:

• Utilized five scenarios: business as usual (BAU), equitable diet (EqD), and three modified IFN input levels (S1, S2, S3).
• Calculated N fertilizer requirements, N budget, N losses, NUE, and gaseous emissions for each scenario up to 2050.

Main Results:

• The EqD scenario necessitates a substantial increase in total N input to 181 kg N ha⁻¹ yr⁻¹, leading to 52 Tg N yr⁻¹ of N input.
• Under EqD, NUE is projected to decrease from 63% to 50%, N surplus to increase from 13 to 90 kg N ha⁻¹ yr⁻¹, and gaseous emissions to rise from 8 to 61 kg N ha⁻¹ yr⁻¹.
• Scenarios S1 and S2, with reduced IFN input, demonstrated significantly lower environmental N loss and improved NUE compared to EqD.

Conclusions:

• Achieving FSS in Africa via the EqD scenario entails considerable environmental N losses.
• The S2 scenario, with an IFN dose of 77 kg N ha⁻¹ yr⁻¹, is recommended, coupled with modern agricultural techniques and increased organic inputs.
• Prioritizing reduced N loss and enhanced NUE is critical for sustainable agricultural development in Africa.