Trend and growth rate of Bajra crop in Gujarat state

Abstract

The trend of area, production and productivity for bajra important factor for successful planning and decision making for the policy makers. Forecasting also plays a crucial role in agricultural, business, industrial, government and institutional planning because many important decisions depend on the anticipated future values of certain variables. The time-series data from 1960-61 to 2012-13 on area, production and productivity of bajra crop for Gujarat were collected from Directorate of Agriculture, Gujarat state, Gandhinagar. The present study was made through fitting of different linear, non-linear and time series models viz., Linear, Quadratic, Cubic, Exponential, Gompertz and Autoregressive Integrated Moving Average (ARIMA), along with their instability index. The results revealed that among different polynomial models for area, productivity of bajra, maximum adjusted R² value of 56.00 per cent and 72.61 per cent was observed in case of the exponential model and third degree polynomial model respectively, in case of ARIMA models, ARIMA (1,1,0), ARIMA (2,1,0)and ARIMA (3,1,0) as the candidate models and based on R² and RMSE values, ARIMA (3,1,0) is the best among ARIMA tested models in area and productivity of bajra crop. The compound growth rates for area, production and productivity were -3.62, 1.86 and 5.44 % annually in bajra crop, respectively. The instability indices area, production and productivity were observed 26.02, 27.63 and 22.34 in bajra crop, respectively. The coefficient of variation for area, production and productivity were observed 39.22, 29.35 and 39.57% in bajra crop, respectively.