Indigenous rice-based lowland farming systems of Nupe, Nigeria

Gadza, a typical village where rice cultivation is carried out by the Nupe ethnic group (Niger State, Central Nigeria) was selected for the survey presented in this paper. Seven different land preparation patterns for rice cultivation were observed in the lowlands, i.e., Togogi kuru, Togoko kuru, Togogi naafena, Togoko naafena, Ewoko, Baragi and Gbaragi. Differences in land preparation patterns appear to be related to the microtoposequence and water regime. Each pattern was seasonally modified by displacing soil, with each sequence of pattern depending on rice and weed growth, water conditions and crop varieties. Moving the soil seemed to be effective for weed control, conservation of soil fertility and water retention. The biomass of weeds in a unit area under the five different land preparation patterns was less than 1/2 to 1/20 of that of the control area. Soil parts that were displaced showed larger amounts of exchangeable bases and lower amounts of exchangeable aluminum than soil parts that were not displaced. It was possible to put forward a hypothesis on the relationship between the microtopography and the seven land preparation patterns. It was suggested that instead of performing leveling and cultivation, the Nupe constructed ridges and mounds varying in shape and size in their traditional paddy fields for water control and land preparation.