African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6848

Full Length Research Paper

Raising crop productivity of smallholder farmers in Sub-Saharan Africa: Long-term Ugandan fertilizer study

Innocent Muhereza
  • Innocent Muhereza
  • Sustainable Rural Enterprise Development Initiative (SREDI), Cooperative Building Plot 47/49 Nkrumah Road, Kampala, Uganda.
  • Google Scholar
Deborah Pritchard
  • Deborah Pritchard
  • Department of Agriculture and Environment, Curtin University, Bentley, Perth, Western, Australia.
  • Google Scholar
David Collins
  • David Collins
  • Boolar Boornap Nursery, Noongar Land Enterprise, Northam, Western Australia.
  • Google Scholar

  •  Received: 12 October 2022
  •  Accepted: 07 February 2023
  •  Published: 30 April 2023


Peri-urban small-holder farms throughout Sub-Saharan Africa (SSA) are predominantly run by women who traditionally use livestock manure as a fertiliser. The rates applied are often inadequate for optimum crop yields contributing to low farmer income and exacerbating food insecurity in the region. This report summarises targeted fertilizer experiments in Uganda from 2010 to 2019 aimed to improve crop yield. Preliminary soil testing in areas of Wakiso and Kampala indicated that nitrogen (N) was the most limiting macro-nutrient and thus the study design initially focused on increasing N, using animal manure, inorganic N fertilizer and/or N fixation using legumes. Plant yields increased by all sources of N although subsequent soil testing revealed issues with acidity, calcium (Ca) and magnesium (Mg)... The study had a strong emphasis on farmer empowerment by involving over 100 farmers and based on training received, farmers then established their own trials with positive yields obtained to lime (CaCO3) and/or Epson salts (MgSO4) in combination with N. The findings highlight the benefits of educating farmers in best nutrient practice as it resulted in higher crop yield and household income and has wider application for peri-urban farmers throughout SSA.

Key words: Peri-urban landholder, cattle manure, nitrogen fertilizer, soil acidity, crop yield.