Measuring the Dis-Equilibrium in Acreage Response of Black Gram (Vigna mungo (L.) Hepper) in Tamil Nadu – A Vector Error Correction Model

Abstract

The study has observed an increasing trend in pulses production, driven mainly by yield improvements. The contributions of area expansion and prices to black gram growth have been erratic, suggesting that these cannot be the sustainable sources of black gram growth. Further, farmers’ area allocation decisions to pulses are not price-dependent, but depend on non price factors, mainly rainfall. However, the growth in pulses production in the long-run must come from technological changes. Numerous past studies on black gram cultivation in Tamil Nadu is criticized for using the weaker Nerlovian Partial Adjustment models and for analytical interpretation through Ordinary Least Square (OLS) creating spurious results for time series data. This problem can be avoided if Econometric technique of co-integration is used. It is for the present paper measuring the dis-Equilibrium in acreage response of black gram by using a vector error correction model. Our unit root analysis indicates that underlying data series were not stationary and are all integrated of order one, that is I(1). The Johansen co-integration approach indicates the presence of a co-integrating relationship in the acreage response model. Black gram acreage is significantly influenced by relative price of black gram, and other competing crops such as groundnut whenever resourceallocation is concerned famers preferred to allocate irrigated land to other competing crops which are more remunerative and high yielding than black gram crop. The black gram supply elasticity’s are found to be inelastic both in the short-and long-run. The long-run and short run price elasticity’s were 0.41 and 0.28, respectively.