Financial performance of fertilization strategies for sustainable soil fertility management in Sudano–Sahelian West Africa 2: profitability of long-term capital investments in rockphosphate

Lamers, John P. A. / Michael Brüntrup / Andreas Buerkert
External Publications (2015)

published on Nutrient Cycling in Agroecosystems February 2015


Phosphorus (P) deficiency is a major impediment to securing crop productivity on the acid, sandy soils of Sudano-Sahelian West Africa (SSWA). However, given the low profitability of many annually applied fertilization strategies with imported P, the effects of yield-enhancing, alternative P-sources, such as rockphosphate (RP), should be considered. Therefore, the financial performance of 14 strategies – including 2 annual and 11 long-term fertilization strategies plus 1 farmers’ practice – were compared in three rainfall zones in SSWA. The comparison comprised the net present value, the annuity, the internal rate of return, and a risk analysis. Agronomic data came from a four-year, five-location trial complemented by information on farming systems, labor demands, and input-output prices. Compared with farmers’ practices, none of the P-fertilization strategies were financially superior at all locations. The financial performance of medium-term RP-strategies tended to increase with rainfall, but remained highly variable. Net returns on land with high rates of RP were often superior to annual inputs of mineral-P, but never the best alternatives. In most cases, the most profitable strategies comprised medium-level RP-applications with or without supplementary hill-placed NPK-fertilizer (also known as “micro-dosing”). The financial performance of medium quantities of RP sometimes increased and sometimes decreased with supplementary nitrogen (N) additions. The combination of hill-placed NPK and broadcast RP as well as N-applications with broadcast RP are alternatives to the use of RP alone. Our results can assist researchers and development institutions in advocating and implementing more effective strategies to enhance agricultural production in SSWA.

About the author

Brüntrup, Michael

Agricultural Economy


Further experts

Aleksandrova, Mariya

Climate risk governance 

Dombrowsky, Ines


Hernandez, Ariel


Houdret, Annabelle

Political Scientist 

Lehmann, Ina

Political Science 

Sakketa, Tekalign Gutu

Agricultural / Development Economics 

Schoderer, Mirja

Environmental Researcher 

Scholz, Imme