Mahamane Adamou’s scientific contributions

Weed competition is a major obstacle to millet cultivation [Pennisetum glaucum (L.) R. Br. (Poaceae)]. The present study was conducted in the south-east of Niger to determine the density of Leucas aspera (Willd.) Link (Lamiaceae) likely to influence millet production, in order to help farmers define technical itineraries for controlling this species. The experimental set-up is a randomized complete block design with four replications and 24 elementary plots. Five types of density (1, 2, 3, 7 and 10 plants) of Leucas aspera around the millet plot were tested. Data collected were mean height, number of plants and plot weight of millet. A one-factor analysis of variance (ANOVA) and Duncan's test at the 5% threshold were used to compare mean heights and yields with the control. Results showed that tolerant density can be estimated at 2 plants/m² of Leucas aspera. Above this critical value, early competition occurs between weed and millet plants from the third week onwards. The lower the density of Leucas aspera, the higher the yield. The average reduction in millet yield from Leucas aspera was 81.95%, with a minimum of 96.55% for the treatment of one Leucas aspera plant and a maximum of 99.66% for the treatment of 10 Leucas aspera plants. These results could help improve weed management in millet cultivation.

Comparative effect of Cassia mimosoides L. (Fabaceae), Leucas aspera (Willd.) Link (Lamiaceae) and Sesbania pachycarpa DC. (Fabaceae) on Millet Yield [Pennisetum glaucum (L.) R. Br. (Poaceae)] in East-Southeast Niger

Weed infestation is, after the negative effects of climate variability and change, the second most important factor in grain reduction. The present study, carried out in the southeast of Niger, aims to determine the weeding period that can influence millet production. The experimental setup used is a complete Fisher block, comprising 36 elementary plots divided into seven dates of manual weeding carried out with a hoe, and subjected to two series of early and late competitions. The study focused on determining the critical weeding period, the relative frequency, density and fresh biomass of weeds and the plot weight of millet. One-factor analysis of variance (ANOVA) and Duncan's test were used to compare yield obtained according to treatment type at P ≤ 0.05. The results revealed that the best yields were obtained on the control plots (2268.75 Kg/ha), the mulched plots (1920 Kg/ha) and the plots maintained according to farmers' practice (1896 Kg/ha). Early, critical and late competition thresholds (21, 28 and 35 days after sowing respectively) were also determined. These results could help improve weed management in millet cultivation.