An evaluation of alternative methods of P application for increased maize production under smallholder farmers' conditions in Kenya

Smallholder farmers in sub-Saharan Africa are confronted by low crop production due to phosphorus deficiency and a limited investment capacity in P inputs. Alternative P fertilizer types are being commercialized which aim at improved P use efficiency through specialized formulations. These products include, amongst others, leaf sprays, seed coatings and conditioners with humic acids. We evaluated these products in pot trials under greenhouse conditions and in multi-locational participatory field trials with farmer groups in three distinct agro-ecological zones in Kenya. The products were applied in conjunction with TSP fertilizer at half the recommended economic rate, as the P supplied through these products was insufficient to attain adequate crop yields. P response was assessed by including treatments without P addition, and TSP applied at half and full recommended rate. In the pot trial, none of the products significantly (P<0.05) increased the shoot dry matter yield of 6-weeks old maize. Seed coating, however, resulted in increased root yield and root-shoot ratio. In the field trials, responses to TSP application were observed in two agro-ecologies, with maize yield increases in the order of 1.4 – 2.6 t ha-1. However, none of the treatments with the different products significantly increased maize yields. Leaf spraying tended to result in yield penalties, particularly when rainfall was insufficient after application of the spray. Correlation analysis revealed that seed treatment has a small positive effect on yield when control yields are low, but not necessarily when response to P fertilizer was large, suggesting that the effect of the treatment way not be directly related to P nutrition. Possibly, seed treatment may have stimulated root development during early stages, which could entail benefits in drought-prone areas and will be further investigated. Our findings indicate that alternative methods of P application have limited benefits for maize production under smallholder farmers' conditions. (Texte intégral)

Bibliographic Details

Main Authors:	Pypers, Pieter, Munyahali, Wivine, Mutegi, Edwin, Musyoki, Mary, Mburu, Margaret, Okalebo, John Robert, Mucheru-Muna, Monicah, Lesueur, Didier
Format:	conference_item biblioteca
Language:	eng
Published:	s.n.
Subjects:	F04 - Fertilisation,
Online Access:	http://agritrop.cirad.fr/558119/ http://agritrop.cirad.fr/558119/1/document_558119.pdf
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