Análise do uso da curva de retenção de água no solo determinada pordiferentes métodos em planilha de manejo de irrigação

Abstract

The region of Lower-middle São Francisco has been nationally and internationally known as growing and exporter area of high quality table grapes. Hence, this research has the objective to compare different methods for determining the soil water retention curve and develop, test and validate a spreadsheet to help decision-making in irrigation scheduling of a table grape croping system. The experiment was carried out in an orchard of grapevines cv. Crimson Seedless, in Petrolina, State of Pernambuco, Brazil. Soil samples were collected for the determination of soil water retention curve by the Arya & Paris, Richards (pressure membrane apparatus) and centrifuge methods. Knowledge of soil water retention characteristics together in situ tensiometer readings were used to determining soil water matric potential, soil moisture, soil water availability; gross irrigation depth and irrigation time by the spreadsheet, and to help the decision-making by growers on irrigation scheduling. The comparison among the retention curves obtained by different methods showed a closer behavior for values greater than 0,1 MPa. The use of spreadsheet resulted in a lower gross irrigation depth and consequently lower irrigation time when compared to the use of crop evapotranspiration to irrigation scheduling, what suggest the combined use of the spreadsheet with agrometeorological data to schedule the water application in this table grape cropping system.