DOI: 10.36347/sajb.2016.v04i11.006

Pages: 1002-1008

Next to drought, poor soil fertility is the single biggest cause of hunger in Africa. The micro-dosing is a fertilizer use technologies tailored to smallholders’ climatic and socioeconomic conditions that is being promoted by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) in low potential areas of the Sahel and southern Africa. This method showed real interest for the poor producers of West Africa. But the long-term application of this practice is yet unknown. In this work, as post-evaluation, we use labeled fertilizer 15N (5.25% atom excess), to determine the fate of nitrogen fertilizer applied with these small doses in semi-arid conditions in Niger. The total amount of labeled fertilizer was split in two periods of application: (1) at sowing, mixed with seeds or deposit under it, with three levels (0.12; 0.24 and 0.48 g Nm-2) and (2) in one of three stages of development (tillering, Steam elongation and earing) with the same dose of 0.8 g Nm-2. The experimental was conducted in completed randomized bloc design with 4 replications. Each bloc has 20 elementary plots of 27 m2 wide, composed of 3 rows of 9 plants. Only 6 of the central plants were considered for the observation and for the labeled nitrogen application. Results demonstrated that mixing the seed with fertilizer before planting leads to lack of 30 to 40% of plant lifting and the nitrogen fertilizer applied by micro-dosing technique to pearl millet crop, is found in very small quantities in the plant and the soil is almost exclusive source (96%) for plant nutrition. Long term application of the micro-dosing technique can have negative effect on soil fertility and should be monitored.