TITLE:
Water infiltration and time to recharge the profile of three soils Rio Grande do Sul, Brazil
AUTHORS:
Afranio Almir Righes, Galileo Adeli Buriol, Valduino Estefanel
KEYWORDS:
Macro Porosity; Rainfall; Drought; Soil Water Storage
JOURNAL NAME:
Agricultural Sciences,
Vol.4 No.11A,
November
28,
2013
ABSTRACT:
The Rio Grande do
Sul-RS State, even with average annual rainfall of 1.721 mm, has shown a lack
of water in the soil for crop production. The study aimed to determine the
variation of annual and seasonal precipitation over the time; determine the
year seasons that can provide the recharge of water into the soil profile and
estimate the time needed to fulfill the soil pore space with water from
effective rainfall with different scenarios of water infiltration. The soil
uses were: oxisol; Red Yellow Podzolic and Planosolo Hydromorphic Eutrophic
respectively in the North, Centre and South of RS State. We determined the
total variation of annual rainfall, mean annual potential evapotranspiration
and the time required to refill the soil profile for three infiltration
scenarios: with fractions 1/2, 2/3 and 3/4 of effective rainfall. In the
regions of Passo Fundo, Santa Maria and Santa Vitóriado Palmar, from 1914 to
2004 there was no reduction in the annual volume of rainfall. Considering that
50% of soil volume and water storage are met and that the fraction 1/2, 2/3 and
3/4 of the effective rainfall infiltrates into the soil, the recharging time
profile varies from 3.7 to 16.6 years, infiltrating 2/3 range from 1.8 to 6.6
years and infiltrating 3/4 of effective precipitation range from 1.2 to 5.1
years, the time required to refill the entire soil porous space. The recovery
of water storage in the soil profile must occur mainly during winter, followed
by spring and fall.