Motorized Tillage Effects on Rice Growth and Yield in the Senegal River Valley: The Case of the Ndiaye Mberess and Lampsar Rice Fields

AbstractThe modernization of rice-growing in Senegal, particularly in the river valley, through the use of agricultural machinery, has made it possible to reduce tillage, increase cultivated areas and improve yields. Nevertheless, the suitability of the machinery used and its effect on rice cultivation remain unknown. Then, the aim of this work was to determine the effects of different motorized tillage on rice growth and yield in field conditions. The study was carried out using a nested experimental design with a primary factor (tillage modality) and a nested secondary factor (tillage depth) and was installed at 2 sites (Ndiaye Mbéress and Lampsar) over 2 successive years. Minimum tillage or offsetting with depths 5 cm (Off5), 10 cm (Off10) and 15 cm (Off15) and conventional tillage or ploughing with depths 20 cm (Lab20), 30 cm (Lab30) and 40 cm (Lab40) were carried out. Thus, 6 treatments, repeated 4 times, were applied in 10 x 10 m plots. The results showed that there was significant variation (P=2.99e-10) in rice height and rooting depth according to treatment. The highest rice height was obtained at Ndiaye Mberess in year 2 (P< 2e-16) for Lab20 (108.7 cm), Lab30 (107.6 cm) and Lab40 (106.4 cm). The Lab40 treatment significantly (P=0.00815) improved rice rooting depth. There were no significant differences between sites, treatments or years in terms of rice yield (P=0.95) with an averaged from 10 to 17.5 kg ha-1. Key words: ploughing, offsetage, irrigated rice, river valley, yield