Phosphorus- The Key to Sustainable Nutrient Management

P- The key to sustainable nutrient managementDescription

Phosphorus (P) is one of three primary macronutrients (NPK) essential to plant and crop productivity. It is considered a macronutrient, as opposed to a micronutrient, because it is required in large quantities and is essential to multiple plant productivity processes. In order to maintain and/or improve sub-Saharan African smallholder crop productivity, phosphorus must be supplied in a sustainable manner. Below we explore the role of P in soil fertility and crop productivity, consider how it is currently recommended and supplied to smallholder farmers, and explore alternative biologically-mediated approaches that could improve productivity, profitability, and sustainability.


  • Improve P cycling efficiency and support sustainable production.
  • A focus on integrated approaches to managing C, N and P together rather than solo use of micronutrients and fertilizers is recommended
  • Agro-diversification to include plants with properties that enhance P-solubilization and cycle P efficiency
  • Targeted application of P in microdoses and directly to plant roots as compost or as fertilizer


  • How to develop management recommendations that take into account the complex factors that influence P supply to crops. This includes soil biology, chemistry, and heterogeneity, complexity of crop rotation, management history, goals of farmers and profitability.
  • Is plant genetic approaches such as improved crops or use of pigeonpea to unlock soil P reserves by enhancing P solubilization a sustainable approach, or will it accelerate soil ‘mining’?
  • Under what circumstances and time frame are sources of P likely to be used in a sustainable and affordable manner? For example, can rock phosphate play a role in supplementation of soil P reserves, or is rock-P too bulky to be profitable?

Learning Lab Resources:

Bonser, A.M., J.P. Lynch and S.S. Snapp. 1996 Gravitrophic response to low P and root architectural traits in common bean. New Phytologist 132:281-288.

Cichy, K.A., G.V. Caldas, S.S. Snapp and M.W. Blair. 2009. QTL analysis of seed iron, zinc, and phosphorus levels in an Andean bean population. Crop Science 49:1742-1750.

Drinkwater, L.E. and S.S. Snapp. 2008. Nutrients in agroecosystems: Rethinking the management paradigm. Advances in Agronomy. 92: 163-186.


Ae N., Arihara J., Okada K., Yoshihara T., Johansen C. 1990. Phosphorus uptake by pigeon pea and its role in cropping systems of the Indian subcontinent. Science 248: 477-480.

Bielders, C.L. and B. Gerard. 2015. Millet response to microdose fertilization in southwestern Niger: effect of antecedent fertility management and environmental factors. Field Crops Research 171:165-175.

Buresh, R.J., P.C. Smithson, and D.T. Heliums. 1997. Building soil phosphorus capital in Africa. In: (Eds. Buresh, R.J., P. A. Sanchez and F. Calhoun) Replenishing Soil Fertility in Africa, Soil Sci. Soc. of Am. Special Publications No. 51.. Pp. 111-149, Madison, WI. 

Tags: Agricultural Economics, Agrobiodiversity, Agroecology, Agronomy, Climate Change, Soil Science, Sustainability Science