Knowing the moisture content is of vital importance to make efficient decisions in a context of water stress. Along these lines, the Institute of Climate and Water of INTA Castelar, through the SEPA platform (Satellite tools for monitoring agricultural production), updated and improved the soil study map and incorporated San Luis and Santiago del Estero .
Most of the agricultural-livestock production in our country is carried out under rainfed systems and depends exclusively on soil water. Among the main applications, the following can be highlighted: the planning of tasks and management strategies, such as the choice of the sowing date or the determination of the opportune moment for fertilization; the estimation of crop yields both locally and regionally; the delimitation of environments; and the identification of periods of deficit and excess of water for crops.
“The new map made from soil charts has a better spatial representation compared to the previous one because a greater amount of data was taken into account,” explained the agronomist Lucas Gusmerotti, from INTA.
The water balance is updated every ten days and as a percentage, it shows the water content of the soils with respect to its maximum retention capacity. “San Luis and Santiago del Estero were included in the estimate, because they have a significant proportion of agricultural-livestock lands in their territory.” The balance of the amount of water in the soil is calculated from meteorological data and information on the characteristics of the layers and vegetation, and the water content of the edaphic profile is calculated by means of a balance between the inflow and outflow of water. on the floor.
SEPA is a platform of the Climate Institute that disseminates satellite and agrometeorological data for key decision making.
Patricio Oricchio, from the same institute, explained that “the source of water entry considered is the rains that are computed through daily records from the INTA and National Meteorological Service (SMN) weather stations. From there a spatial interpolation is made and accumulated precipitation maps are obtained for a period of ten days ”.
The source of water output considered by this model is the actual evapotranspiration (ET), which is the amount of water that is effectively evaporated from the soil surface and transpired by the vegetation cover. According to Oricchio, “an estimate is made using two variables: the surface temperature and the Normalized Vegetation Index (NVI), which is obtained by the Viirs sensor, with a spatial resolution of 375 meters”.
The specialists affirmed that the balance also considers the maximum useful water retention capacity of the region’s soils, “this is defined as the usable water, or potentially extractable, by the crops in the root growth zone, and constitutes the fraction of soil water that can be lost through evapotranspiration ”, they assured.
The information was obtained from soil maps prepared by INTA of the provinces involved at a scale of 1: 50,000 (Buenos Aires, Córdoba and Santa Fe), 1: 100,000 (Entre Ríos, La Pampa and San Luis) and 1: 500,000 (for Santiago del Estero).
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