First Weeding using the Cono-Weeder
 
We received a model of a Sri Lankan “Cono-Weeder” (or conical weeder) from Tim Krupnik, a SRI researcher in Senegal.  
 
See the video of the first field test in Daouda’s field 17 days after transplanting. The test was successful, showing multiple advantages over hand weeding (described below). The weeder works very well in the heavy clay soils of Goundam and Dire.
July 14, 2008
According to SRI guidelines, the first weeding should be done 20 days after transplanting when the plants are well established. Ideally, it should be repeated every 10 days, until either the plants are too large to allow the weeder to pass through the rows, or until the plants reach the development stage of tiller elongation and panicle initiation.
 
Standing water forms puddles, creating anaerobic conditions on the soil surface (left side of the field in picture 1). The cono-weeder redistributes water across the entire plot between the planting lines (right side of the field in picture 1, and the entire plot in picture 2). This not only provides additional irrigation to the plants but also increases fertilization directly to the rooting zone, because water mixes with soil and incorporated manure. The weeding also helps to level the field.  
 
Advantages of Using the Cono-Weeder  
 
Ideally the field should be “cross-weeded”, that is, the weeder should run both ways through the rows: up-and-down, and across. This increases irrigation, fertilization, and weed control, and slightly mounds the soil around the base of each plant.
It is easiest to weed when a very shallow layer of water covers the plot. In the pictures below, the weeder is not working optimally, soil sticks to the rotating cones, and it takes considerable effort to push the weeder through the drier mud. We also see in the pictures below how the weeder is working superficially the soils.  
 
In the plot shown above, Daouda was not able to finish weeding his entire plot because part of it was too dry to use the weeder properly. Two days (!) later, we could clearly observe differences in plant vigor and plant color between the weeded and unweeded sections of the field (picture below) . Plants in the weeded section were a darker green and seemed invigorated compared to those in the unweeded section.