Uso eficiente del agua de riego mediante sondas de capacitancia fdr, en el cultivo de banano

Abstract

Water is the main limiting factor in agricultural production, to meet the water needs of crops has been used supplementary irrigation as a tool not only to increase productivity, but also to reduce inter-annual variability in crop yields, especially in the dry season, taking into account the periods of low rainfall that we have in the province of El Oro, so it is vitally important to know the water content in the soil to understand the behavior of a crop against variations thereof. Among the methods of measuring water in the soil is the capacitance probe FDR which is an indirect measurement instrument that allows to obtain accurate and immediate information on the variations of moisture content in the various strata of the soil. In order to efficiently manage irrigation water in a banana farm located in the parish of La Peaña in Pasaje canton, soil moisture values were taken for 16 weeks, before, during and after the rainy season, in which a reading was made every 15 days during the months of February and June, for this purpose PVC pipes were installed previously 54 mm in diameter and a length of 1.0 m , located at 15 points obtained through a 75m x 75m grid system traced on the farm with the help of Autocad 2017 software. Samples were taken from each grid every 10 cm, up to a profile of 50 cm, to determine the physical properties such as apparent density, real density, porosity percentage and textural class, in addition to taking samples to determine moisture content through the gravimetric method. The crop evapotranspiration (Etc) was calculated using the FAO software called Cropwat and with this the irrigation needs for the months of study were obtained, and subsequently a water balance was made with the moisture contents obtained with the FDR probe and with the gravimetric method in that period; thematic maps of the water content in the soil divided into 3 levels were made, being the months of February and March a period where rainfall was high and these covered the water demand of the crop, not so, the months of April, May and June where rainfall was low and moisture content was supplemented with sheets of water applied with the sprinkler irrigation system installed, During the months analyzed, the areas with the highest and lowest moisture content in the soil were identified and with this a watering time was obtained for each area. During these months, the watering times for the areas with the lowest moisture content vary between 2:45 and 2:50 hours, while for areas with higher soil moisture content irrigation times varied between 2:05 and 2:15 hours, thus optimizing the use of irrigation water lowering production costs in banana cultivation. In order to evaluate the behavior of the probe readings, the Pearson correlation coefficient (r=0.943), the determination coefficient (R2=0.842), and the linear regression equation y=0.98+0.98x were evaluated, which indicates that the FDR probe is a reliable method for the determination of the sheet of water in the soil profile and is ideal for the estimations of the volume of water used for irrigation.