Land evaluation in a salt-affected irrigated district using an index of productive potential

The indiscriminate allocation of funds supporting agricultural policies can lead to land misuse, with undesirable effects either on the shorter to mid -term productivity or on the environment. This article proposes a methodolo gy, based on land rating, that can be useful to land-use planning or to dec ide about environmental protection measures. The methodology is applied to the land evaluation of a 260-km(2) semiarid irrigated area with salt-affect ed soils. The avail able soil map is at 1:100,000 scale and its mapping uni ts are used for the land evaluation with the FAO framework. These data are then elaborated using the index value method. This procedure gives a map of land evaluation units and a table that rates the productive potential of t hese units for six crops: alfalfa, barley, maize. rice, sunflower, and whea t.