Effect of late nitrogen application on rice yield, grain quality and profitability in the Senegal River valley

Abstract

The effect of an additional nitrogen (N) application of 30 kg N ha −1 at booting on rice yield and grain quality was investigated with 30 farmers in the Senegal River valley during the 1997 wet season (WS) and 23 farmers during the 1998 dry season (DS). Rice yields increased significantly as a result of an extra late N application on top of two N-dressings with a total of about 120 kg N ha −1 in farmer fields. Yield gains were about 1.0 t ha −1 during the 1998 DS and about 0.4 t ha −1 during the 1997 WS. Grain quality was improved through a higher milling recovery (3% increase in both seasons) and a higher percentage of head rice (30% higher in the 1997 WS and 60% higher in the 1998 DS). Benefit to cost ratios of the third nitrogen application for farmers ranged from 2.8 in the WS to 5.4 in the DS. Sorting milled rice resulted in net additional benefits for rice millers, especially in the DS, due to a higher head rice ratio. It was concluded that a third N application can raise both yield levels and grain quality in the Senegal River valley, with potential benefits for farmers and rice millers.