Excessive alkalinity of fertigation waters can create a series of problems such as the blockage of water emitters, carbonate precipitation and the reduction of micronutrient availability for crops. A software, ALKA 1.0, was developed in CLIPPER 5.2, to help manage the alkalinity of those waters. The Program runs in computers IBM-PC/XT/AT/PENTIUM or other 100% compatible. It is initiated with the input of the actual irrigation water pH, its total alkalinity, and the irrigation sheet used during the crop cycle from which ALKA 1.0 calculates the amounts of HCl, HNO3, H2SO4 and H3PO4 to be added to the irrigation water to reach the target pH, specified by the user. Besides the volume of each acid, the Program calculates the amount of introduced nutrients by each one of the acids, and their total cost. For this, the density and purity (%w/w) of each acid, as well as their cost, per liter, have to be supplied by the user. ALKA 1.0 still offers the option of mixing different acids seeking the removal of the excessive alkalinity of the water, and also the appropriate nutrient (N, P, S) balance for the crop. Finally, ALKA 1.0 also works with databases with prior information on the origin (place) and sources (rivers, wells, lagoons, and others) of several waters, besides the pH and total alkalinity of these waters. In this way, the management of the alkalinity of those waters can be planned for a particular county, a given source, pH, and other characteristics defined by the user. ALKA 1.0 was validated with a mixture of CO3(2-) and HCO3-, pH 9.19, analyzing the program's performance in calculating acid volumes to decrease the solution pH to 7.0, 6.5 and 5.5, with quite satisfactory results. Natural water samples were also used to validate the program's performance with the decreasing of the samples'pH to 6.5 and 6.0 being quite satisfactory. The program was not efficient in reducing natural samples pH to 5.0.
alkalinity handling; alkaline waters; software