Mathematical model for scheduling irrigation for swamp rice in Port Harcourt L.G.A, Nigeria
The thirst for increased food production and management of our natural resources (water) is increasing on daily basis and there is a great need for proper utilization of such important resource. Nigerian farmers today still rely on rainfall for cultivation of food crops, this is simply because they do not have the knowledge of irrigation scheduling and timing and it has affected the rate at which food crops are produced in our country. The formula of a mathematical model that can predict the required amount of irrigation water for swamp rice in Port Harcourt L.G.A. of Nigeria was the main objective of this work. Thus, the formula or the model is given as; d2 = d1 + ERF + I + Ip– ETc. The maximum and minimum values of water depth (dmax and dmin) required in the field were determined to be 320.32mm and160mm respectively. The result showed that, the model was able to augment the water need of the planted crop except in weeks 5 and 6 which have the values of d2 (final water depth in the field) as 135.69mm and 120.07mm respectively. While the mother model indicated that the planted crops will be under severe water stress because the values of their d2 were below the allowable range of water depletion except in weeks 1,7,10,16 and 17 with their d2 values to be; 178.50mm, 181.47mm, 162.11mm, 198.80mm and 187.60mm respectively. Water application is made on the field whenever the water level is at or below dmin. The result of the correlation analysis for the two models was obtained to be 0.002796. This showed that the two models have a strong non linear relationship between them.
Keywords: Mathematical model, irrigation, Water, swamp rice