Response Surface Methodology Approach to the Optimization of Potato(Solanum tuberosum) Tuber Yield Using Second-Order Rotatable Design

One of the major concerns among developing countries in recent decades is the effect of declining food security with ever-growing population. Hence, the importance of adopting cost effective farming methods has led to the development of various statistical methods to alleviate food insecurity. Among these methods, CCD has gained significant attention to its application in agriculture. In this paper, the response surface methodology (RSM) was applied in order to determine the effects of the factors potassium (K), nitrogen (N) and phosphorus (P) on the yield of potato tuber. The predicted values for the yield of potato tuber by the response functions were in a very close agreement with experimental data (R2=90%). The second-order model was developed by solving the parameters of the regression equation using the method of least squares. The optimal combinations of the factors potassium (K), nitrogen (N) and phosphorus (P) with yield as the response of interest were determined by analyzing the 3D response surface plots and using the method of steepest ascent. Using ridge analysis method which corresponds to the method of steepest ascent, the optimal yield of potato tuber was estimated to be 29.26 t ha-1 which is much higher than the current national target of 14 t ha-1 with optimum factor levels being K=35.36 kg K2o ha-1, N=78.71 Kg N ha-1 and P=160.69 Kg P=160.69 kg P2o5ha-1, respectively. Nitrogen and phosphorous had a significant positive linear effects on the potato tuber yield. Based on the results, it can be concluded that the response surface methodology is a suitable approach for determining the optimal conditions of the selected fertilizer types.