Abstract

Food grains, which are major sources of energy and vital nutrients, are in short supply in many Nigerian households. Government, at various times, has embarked on importation of these food items to augment local supply. The main objective of this study was to examine the various determinants of the quantities of cereals (rice, maize, millet and sorghum) that are supplied into the Nigerian economy. Statistical information on domestic and imported quantities of these grains was obtained for some 37 years (1970 to 2007). Some economic models, including equilibrium output supply function and co-integration models were used. An all -time maximum output of 8,090,000 tonnes was recorded for rice followed by millet with 7,100,000 tonnes with mean values of 4,228,900.47; 4477, 026.31; 3,596,894.73 and 2,034,719.00 for maize, rice, millet and sorghum respectively. Rainfall was consistent for all the four crops with an all- time maximum of 136.41 mm rainfall and mean value of 37.93 mm. Trace test reveals that the hypothesis of no co-integration (Ho: r = 0) is rejected at p < 0.05; given that the calculated Trace test statistic (98.45) is higher than the critical value (95.75) at p < 0.05. However, the test that r ≤ 1 could not be rejected. Thus, Trace test reveals that the series in maize output supply response model are co-integrated, with only 1 co-integrating equation existing between them.  Producer price of rice was positive and statistically significant at 1% level. The output response of rice to hectarage was not statistically significant but was positive. Rice importation showed a negative sign and was statistically insignificant in Nigeria.  There is the tendency for the price of agricultural products to drop, which may consequently reduce the level of domestic production and thus discourage commercial production. Maize output, hectarage, producer price and import quantities were non-stationary series. Thus, they cannot be included in their levels in least square regression models. The insignificant impact of prices on millet output could have arisen from the fact that lagged prices are better considered by the farmers.

Key words: Market supply, economic models, food grains, importation, production output.