Amelioration de la production du niebe sur les terres de barre degradees du Benin

Abstract

Cow pea production on ferrallitic soil in the southern of Benin is affected by nutrient depletion. The objective of this trial is to compare the effect of fertilization and the traditional cutting practice of young leaves of two cowpea late varieties: creeping V1 and erected V2. On six farmerfs fields, in 2002 and 2003 a split-plot design of two factors (fertilizer and variety) has been conducted, to evaluate the effect of three fertilizer formulas: P47K25N45, P47K50N45 and P47K50N30. Soil fertility, soil cover capacity and cow pea production were evaluated. The cow pea grain yield has increased at 114% for V1 and 106% for V2 in
2002, and 141% and 123% respectively for V1 and V2 in 2003 relatively to the controls. The effect of N and K fertilization on grain yield is significantly higher than control at 5 % threshold; but no significant difference is observed between the studied formulas. A traditional young leaf cutting practice has stimulated at 10% the grain yield of erected variety, but has decreased at 21% creeping variety. The cow pea plant growth has linear regression model (R2
. 0.852), while his soil cover capacity has polynomial hyperbolic model (R2 . 0.965).

La production de niebe sur les terres de barre du sud Benin est affectee par le deficit en nutriments des sols. L'objectif de ce travail est de comparer l'effet de la fumure et de la cueillette traditionnelle des
feuilles de varietes tardives de niebe : rampante V1 et erigee V2. Chez six paysans, en 2002 et 2003 dans un dispositif Split plot de facteur principal (fumure) et secondaire (variete) trois fumures P47K25N45,
P47K50N45 et P47K50N30 pre- identifiees en pots ont ete testees. Les observations ont porte sur la fertilite du sol, la couverture du sol et le rendement. Les rendements grain du niebe ont augmente de 114% sous V1 et 106% sous V2 en 2002 contre 141% et 123% respectivement pour V1 et V2 en 2003 par rapport aux temoins. Les fumures potassiques et azotees testees nfont eu aucune difference significative au seuil de 5% entre elles. La cueillette traditionnelle des feuilles de niebe a stimule le rendement de 10% sur la variete erigee, mais a baisse de 21% celui de la variete rampante. La croissance des plants a suivi une regression lineaire (R2. 0.852) alors que le recouvrement est polynomial hyperbolique (R2. 0.965).