Resumen

RUDA, Ester et al. Quality of Ground Water Used for Supplementary Irrigation on Argiudolls of Central Santa Fe, Argentina. Agric. Téc. [online]. 2005, vol.65, n.4, pp.411-420. ISSN 0365-2807.  http://dx.doi.org/10.4067/S0365-28072005000400007.

Considering that the ground water used for supplementary irrigation has variable chemical characteristics that may affect soil properties, a typical Argiudoll (A₁) and an aquic Argiudoll(A_p) were treated with artificial irrigation waters with different sodium adsorption ratios (RAS): 6.3, 11.0, 16.5, 21.5 and 24.3. The following tests were carried out: carbon (Walckey Black); pH (1:2.5) (by pHmeter); cation exchange capacity (CIC); Ca²⁺ , Mg²⁺ and H⁺ (volumetric method) and Na⁺ and K⁺ (spectroscope of atomic emissions). The objectives of this work were to find prediction models such as Na exchange percentage (PSI) vs. RAS, pH vs. RAS and pH vs. adsorbed Na; to analyze if there is a limit value for adsorbed Na; to determine the evolution of organic matter, and to compare PSI using the obtained prediction. No Na adsorption limit value was found, but a carbon loss was encountered in relation to initial values. The following prediction models were determined: PSI vs. RAS: quadratic for A_p (p ≤ 0.0261; r²_aj = 0.839) and linear for A₁ (p < 10^-4; r²_aj = 0.828); pH vs. Na: quadratic (p < 10^-4; r²_aj = 0.991) for A_p and A₁ (p < 10^-4; r²_aj = 0.995), and pH vs. RAS: also quadratic for A_p (p < 10^-4; r²_aj = 0.979) and A₁ (p ≤ 0.0011; r²_aj = 0.911). PSI errors were lower with the prediction equations than with Richards’ equation. The models found allow diagnosis of the sodicity and pH that the studied Argiudolls acquire when subjected to the irrigation water with different levels of RAS.

Palabras clave : soil; sodium adsorption; statistical models.