Instabilidade de preço e elasticidade de oferta

O caso do algodão no estado de São Paulo

Resumo

This study deals wilh economic aspects of cotton production in the state of São Paulo, the major Brazilian producer.

The knowledge of the structure of product supply is very important for orientation of policies of production and price. Thus, in this study, demand is on an estimated function of supply of cotton.

The data was obtained from a time series (1948/70), that furnished area planted, price of cotton, price of corn, other information, and was published by the Instituto de Economia Agrícola da Secretaria da Agricultura do Estado de São Paulo (5).

The Nerlovian model of distributed lags was used to esti- mate the supply with the inclusion of the standard deviation variable of the price of cotton, and with an objective to obtain an idea of the producer response to variation in prices (6).

The orthodox least squares method was used to fit the function.

The Student "t" test was used to verify the significance of the coeficients, and the Durbin-Watson test was used to check for the existance of serial correlation among the residuais.

The estimated quation of area planted was:

PF = 2.511 + 73.325X1 - 1.229X2 + 0.657X4 

                      (39.780)       (1.473)        (0.122)

The coeficients obtained are consistant with usual expectations, were significantly different fromzero at the 5, 25 and 0.5% level respectively, and Durbin-Watson test showed that there was no serial correlation among the residuals.

The short run elasticities obtained were 0.39 for the price of cotton/corn, - 0.08 for the standard deviation of price, and 0.343 for the adjustment variable

The equation in the long run was:

? = 7.321 + 213.776X1 - 3.583X2

and the elasticitiaes were 1.45 for the cotton price relationship. (X1), and -0.23 for the standard deviation of the price of cotton (Xz).

It can be said that the results obtained for the area planted with cotton, tend to underestimate the true pro- duction, response since the state of São Paulo is adopting modern technology for the production of cotton.

In view of the importance of cotton to the state and to Brazil, a policy of establishing minimum prices for a period of three years, without a doubt, will contribute substatially to increase production and consequently strenght the position of Brazil in the world market of cotton.