Drought risk in the pampean region using soil water storage analysis

FORTE LAY, J. A., O. E. SCARPATI, L. SPESCHA, L. AND A. D CAPRIOLO

Environmental change and rational water use

Orientación Gráfica

Lugar: Buenos Aires; Año: 2007; p. 146 - 168

This paper analyses the drought risk in the Pampean region using statistical results of soil water storage. These are calculated by daily soil water balance whose methodology has been tested with in situ obtained values and has been described in published papers and newly, it is used to monitor the soil moisture and its anomalies. A new concept is proposed in this paper, to define a level of drought or minimum level of soil water storage, for the entire region as the minimum optimum for crops. Over this moisture level, crops can yield with all their potential without being affected by soil water deficit and hence, is proposed to obtain the occurrence probability of values under that minimum, for an average of a determined time period (a month, a ten days period, a week, etc.). The established level of drought is considered as the half of the available soil water capacity, which coincides with the minimum limit of optimum soil moisture (so called conditional drought level). The use of lower drought levels, like permanent wilting point, is proposed too, to evaluate the risk of more dangerous situations, like those conducting to crops loses. The possibility of the use of crop and/or soil management coefficients, allowing a more particular evaluation for different agricultural exploitation, is also analyzed. The need of soil water economy can be deduced by means of an appropriate soil management and /or the implementation of complementary irrigation, when it is possible.