Enhanced Rainwater Productivity of Pearl Millet ( Pennisetum glaucum ) Through In‐Field Rainwater Harvesting and Nitrogen Microdosing in Semiarid Zimbabwe

Abstract

The small‐scale farmers of semiarid southern Africa are experiencing chronic water and nutrient shortages due to climate change; however, very few initiatives have been put in place to optimize the production of underutilized drought‐tolerant small grains that currently give poor yields of less than 0.8 t ha −1 using conventional planting techniques. The current experiment was undertaken to find out whether the combination of in‐field rainwater harvesting (IRWH) and nitrogen microdosing (MD) would enhance pearl millet yield and improve water use efficiency. An experiment was conducted for two seasons at Chiredzi, Zimbabwe, in sandy‐loam soils involving two planting systems (flat and IRWH with tied ridges and runoff strips of 0.3 m) and three nitrogen fertilizer doses (0 kg N ha −1 , MD with 25 kg N ha −1 , and a full dose of 60 kg N ha −1 ). Results revealed that the IRWH/MD combination gave the highest pearl millet yield of 1.92 t ha −1 (220% higher compared to the flat control of 0.60 t ha −1 ), and the WUE increased from 2.2 kg ha −1 mm −1 (for the flat control) to 6.8 kg ha −1 mm −1 for the IRWH/MD combination. In the context of the IRWH system, nitrogen MD proved to be statistically like the application of the full amount of nitrogen, leading to 58% of fertilizer saving. Thus, we believe that rainwater harvesting along with nitrogen MD could be considered as a low‐cost, climate‐smart solution for pearl millet production.