Sowing Rice in Furrows and its Effect on Soil Moisture and Seedling Emergence under Rainfed Conditions in Benin, West Africa

抄録

In the rainfed regions of West Africa, rice production is greatly influenced by rainfall quantity and frequency, especially the upland ecologies. Establishing alternative methods to improve soil water retention can be the key to stable yield increases. Experiments were conducted twice on 7–9 fields to evaluate furrow sowing and its effects on seedling emergence under rainfed conditions in central Benin in 2015. Narrow (3 cm wide) and wide (10 cm wide) furrows were compared against conventionally tilled plots under dry and wet conditions. Under the former conditions, the soil moisture in the furrow was 2.5% higher and the emergence rate was 16–25% higher than in control. Emergence was the earliest in the narrow furrow. Under wet conditions, the soil moisture in the furrow was 5% higher than in control, while the emergence rate was the highest in the wide furrow, followed by control and the narrow furrow. Emergence was earlier in the wide furrow and control than in the narrow furrow. Furrow sowing was effective in increasing soil moisture and emergence. However, when the soil moisture was higher than around 10%, the narrow furrow had a negative effect on emergence while the wide furrow continued to have a positive one. These results suggest that while the narrow furrow was effective in very dry soils, the wide furrow had greater adaptability to soil moisture variations and retained soil moisture for better plant establishment under rainfed conditions.