Abordagem integrada para manejo da irrigação em região semi-árida: experimentação e modelagem

Abstract

In the Brazilian semi-arid the family agriculture comprises a financial support to small poor communities, contributing for reduction of the rural exodus. However, due to the adverse climatic conditions, as the concentration of the rainfall in some months during the year, the irrigation becomes indispensable for the practising agriculture. The objective of the work was of gaging the model SALTMED during the station of growth of the cabbage so that the same can be used to analyze alternatives of integrated handling of irrigation in systems of the semiarid considering aspects of the natural resources (soil and water), climate, culture and overhead irrigation in a frequency of watering of 24 hours and to validate him/it frequently for the treatments of 12 and 48 hours in areas with soil of the alluvial type of medium texture with salinity potentials. The experiment was driven in irrigated lot of Our Finance Mrs. of Rosario, municipal district of Pesqueira-PE, Rural of the State of Pernambuco. The irrigation sheets, for the frequencies of 12, 24 and 48 hours, they were calculated with base in the culture coefficient (Kc) and in the reference evapotranspiração of the (Eto) from pan. During the cycle of the culture the humidity contents were monitored in the depths of 20 and 40 cm that were compared with values made calculations by SALTMED for calibration and validation. Also the salinity of the soil was measured, for the treatment frequently of 24 hours. The productivity of the culture of the cabbage was evaluated for the different frequencies. It was verified experimentally that the three frequencies used in the study can be used as handling alternative for reduction of the salinity of the soil, with prominence for them frequency of 12 and 48 hours. The results also showed that the model SALTMED answered satisfactorily in the prediction of the humidity data and of salinity of the soil, for the tested conditions. Therefore the model can be used for forecast of handling of similar irrigation, in way to provide larger productivities of cultures sensitive olerícolas the salinity, varying sheet of water, quality of the water and types of overhead irrigations.