Economical consideration for the evaluation of water consumption

摘要

A number of preliminary studies on the Tavoliere delle Puglie irrigation scheme, Italy, showed an important difference between the water requirements of some crops (olives, grapes, vegetables and wheat), computed with appropriate methodologies, andthe volume effectively supplied by farmers. The comparison, based on field data recorded form 1991 up to date, showed that farmers utilize water volumes considerably lower than the estimated ones. In order to understand the reasons leading this behaviourpattern, some economical parameters (i.e. price of the water, variable according to the supplied class of volume, fix costs of production, variable costs of production) were identified. The yield response of crops to water was estimated, crop by crop, on the base of field investigations on different farmers. The water volume effectively supplied was recorded on the flow meter used by each farmer, while data on crop yields were obtained by interview. In this preliminary study, the elaboration was referred to the irrigation season 1991. A mathematical model was developed to calculate the optimal water volume to be supplied to the crops and the optimal area to be cultivated by each crop. The results of the model were compared with the recorded water volumes and areas. It was shown that farmers in the examined irrigation scheme use water in a sound efficient way.