The introduction of animal traction into inland valley regions. 2. Dry season cultivation and the use of herbicides in rice

Rice was grown in an inland valley (fadama) region of central Nigeria. Plots were cultivated using oxen either in the dry season or at the beginning of the wet season. Around 25% more time was required for dry season cultivation but this enabled an average saving of 53·5 h/ha during the most critical time of the year at the beginning of the wet season. Total time for all operations during the year was similar (2075 and 2150 h/ha for dry and wet season respectively) of which most was spent on weeding (1388 and 1527 h/ha). Weeding time could be reduced by the application of pre-emergence herbicide to 1042 and 1247 h/ha for dry and wet season cultivation respectively. Grain yields were 4·0, 4·8, 4·2 and 4·6 t dry matter/ha for dry season/no herbicide, dry season/herbicide, wet season/no herbicide, and wet season/herbicide respectively. Similarly, straw yields were 4·8, 7·0, 5·7 and 7·4 t/ha. None of the differences in yield was statistically significant.