Uniformity trials are needed to determine suitable shape and size of the plot for knowing the nature and extent of fertility variation in land, so that if some treatment has given good result, one should be confirmed that it is true and is not due to some other unknown reason. In these trials, a particular variety of crop is sown on the entire experimental field and throughout the growing season it is managed uniformly. The C.V. per cent per unit size decreased with the increase in plot size by increasing the length, the width or both. The greatest reduction in coefficient of variability was up to some point of unit plot size and thereafter the decrease was not proportional to the amount of land utilized. Therefore, obtain unit plot size was considered optimum.