A New Approach to Estimating National Maize Production in Nigeria.

Estimates of crop yield are needed annually in Nigeria to determine the country’s level of attainment of self-sufficiency and poverty alleviation. The estimates are also useful in the determination of yield gap. Annually, the Food and Agriculture Organization (FAO) of the United Nations publishes total crop production, productivity, and land area covered by the crop for each region of the world, and Nigeria is well covered in the efforts. There is, however, an ongoing controversy about the accuracy of maize (Zea mays L.) productivity estimates by the FAO. An approach that collected actual yield data from farmers’ field was proposed. The approach was used in nearly 4000 farms distributed in all agroecological zones of Nigeria. In the study, a 5 m x 5 m quadrant was made on each farm from which were determined the number of plants, number of ears, ear weight and grain yield. Grain yield ranged from 1.2 to 8.0 t ha^-1, with a mean of 4.14 ± 0.179 t ha^-1.  Only about 13% of the farms had grain yield <3 t ha^-1 while 44% produced yield ≥ 5 t ha^-1 There were highly significant differences among agroecological zones, the most productive being the Guinea savanna. Number and weight of ears were positively correlated with grain yield (r = 0.52 and 0.59, respectively). It may be concluded that maize grain yield in Nigeria is now greater than 4 t ha^-1, unlike < 2 t ha^-1 estimated by FAO.