Unravelling causes of poor crop response to applied N and P fertilizers on African soils

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dc.creatorSileshi, Gudeta W.
dc.creatorKihara, Job Maguta
dc.creatorTamene, Lulseged D.
dc.creatorVanlauwe, Bernard
dc.creatorPhiri, Elijah
dc.creatorJama, Bashir
dc.date2022
dc.date2022-02-15T10:35:31Z
dc.date2022-02-15T10:35:31Z
dc.date.accessioned2026-06-27T15:53:46Z
dc.descriptionA number of studies across sub-Saharan Africa have recently reported poor crop responses and low agronomic use efficiencies of applied nitrogen (AEN), phosphorus (AEP) and potassium (AEK). However, the conditions under which non-responsiveness occurs, its underlying causes and its probability of occurrence on different soil types are not well understood. Using data from 542 sites and 14 soil types in 23 African countries, we provide novel insights into the linkage between lack of response to applied N, P and K, the mineralogy of soils and their resilience to erosion. We estimated mean responses as well as the probabilities (ϕ) of no response in terms of response ratio (RR), yield gain (YG) and agronomic efficiency. Here we defined ‘no response’ as zero agronomic response to fertilizer inputs in a given site and year indexed by either RR ≤ 1, AEN ≤ 0, AEP ≤ 0 or AEK ≤ 0. The highest risks of no response were recorded on the iron-rich Plinthosols (ϕ = 0.26) followed by the aluminium-rich Alisols (ϕ = 0.16) and the erosion-prone Lixisols (ϕ = 0.16) and Leptosols (ϕ = 0.13). In terms of yield gains, the highest risk of low response (i.e., YG ≤ 0.5) was recorded on Alisols (ϕ = 0.47) and the lowest on Fluvisols (ϕ = 0.05). Cambisols, Fluvisols, Luvisols and Nitisols were deemed highly responsive to NPK fertilizer. The risks of no response were significantly higher on soils derived from siliceous than mafic parent materials, soil types with low resilience to erosion, soils with low-activity clays and high P fixation capacity. It is concluded that maize grain yields can exceed 3 t ha-1 with high probability (ϕ > 0.80) on Andosols, Nitisols and Vertisols, but with very low probability (ϕ < 0.30) on Alisols and Arenosols. It is also concluded that across soil types and agroecological zones, the risk of no response is up to two times more on farmers’ fields than on research stations. Here, we discuss the implications of these finding for the design and location of future agronomic trials. We also provide insights to guide the targeting of fertilizer subsidies where nutrients can be more efficiently used.
dc.formatapplication/pdf
dc.identifierhttps://hdl.handle.net/10568/118134
dc.identifier.urihttp://hdl.handle.net/123456789/116702
dc.languageen
dc.publisherCambridge University Press
dc.rightsOpen Access
dc.sourceSileshi, G.W.; Kihara, J.; Tamene, L.; Vanlauwe, B.; Phiri, E.; Jama, B. (2022) Unravelling causes of poor crop response to applied N and P fertilizers on African soils. Experimental Agriculture On line First Paper (08 February 2022) 17 p. ISSN: 0014-4797
dc.subjectcrop production
dc.subjectsoil management
dc.subjectfertilizer application
dc.subjectproducción vegetal
dc.subjectmanejo del suelo
dc.subjectaplicación de abonos
dc.titleUnravelling causes of poor crop response to applied N and P fertilizers on African soils
dc.typeJournal Article

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Instituto Internacional de Agricultura Tropical (IITA)