[Results of an investigation on the degree of sorghum commercialisation level on the producer level : work document]

commercialisation consumer prices direct marketing encuestas exploitation agricole familiale family farms farine flours grain granos harinas income market stabilization marketing mercadeo oferta y demanda offre et demande precio al consumidor precio al productor producer prices renta revenu sorgho sorghum grain supply balance surveys venta directa vente directe