Soil:Water Suspension Salinity Tests

The salinity of the dreamlo is a limiting factor in the management of sports surfaces. Until the 1950s this was analysed through the test of saturated pasteHowever, the use of soil:water suspensions at different ratios such as 1.1, 1:2, 1:5 and 1:10 is a quicker and easier process than obtaining saturated paste.

Studies have been carried out on different soil textures: sandy, loamy and clayey, in order to correlate the results and arrive at the values that a saturated paste test would provide, Sonmez et al., 2008.

Soil:water Regression equation r²

Sandy soil

1:1 ECe (dSm‾¹) =2.42 x 0.98

1:2.5 ECe=4.41 and 0.99

1:5 ECe=7.98 z 0.98

Thus, the measurement of 1 dS/m in EC measured in a 1:1 soil:water suspension is the same as 2.42 dS/m measured in saturated paste. Remember that the tolerances of the different varieties are recorded in the bibliography in units measured in saturated paste tests and therefore, if the results are given by other tests, it is necessary to know their equivalence to the reference test.

Loam soil

1:1 ECe=2.06 x 0.99

1:2.5 ECe=3.96 and 0.99

1:5 ECe=7.62 z 0.99

Clay soil

1:1 ECe=1.96 x 0.99

1:2.5 ECe=3.75 and 0.99

1:5 ECe=7.19 z 0.98

Likewise, the concentrations of the different solutes in these different soil:water surfaces correlated with those of saturated paste have been determined according to the following table (we show only those with a sandy texture typical of greens):

Parameter regression equation r²

1:1 soil:water suspensions

EC, dSm‾¹ SP=2.42 x 0.98

Cl, mel‾¹ SP=3.33 x 0.92

K, mel‾¹ SP=1.31 x 0.41

Na, mel‾¹ SP=2.55 x 0.99

Ca, mel‾¹ SP=3.14 x 0.59

Mg, mel‾¹ SP=4.88 x 0.97

Thus, if we measure the Chlorine in a 1:1 soil:water suspension and there is 1 me/l of Cl, this is the same as saying that there are 2.55 me/l measured in saturated paste.

Suspensions 1.2.5 soil:water

EC,dSm‾¹ SP=4.41 y 0.99

Cl, mel‾¹ SP=6.02 and 0.99

K, mel‾¹ SP=2.49y 0.81

Na,mel‾¹ SP=4.48y 0.99

Ca,mel‾¹ SP=5.36y 0.99

Mg,me‾¹ SP=10.52y 0.99

1:5 soil:water suspensions

EC,dSm‾¹ SP=7.98z 0.98

Cl,mel‾¹ SP=10.24z 0.98

K,mel‾¹ SP=3.08z 0.67

Na,mel‾¹ SP=8.42z 0.99

Ca,mel‾¹ SP=9.75z 0.97

Mg,mel‾¹ SP=16.40z 0.96

Based on the results, which show a very high correlation with the regression equations obtained, it can be concluded that the 1:1, 1:2.5 and 1:5 soil:water extracts can be used to estimate the conductivity of the saturated paste extract and the concentrations of the various solutes in the soil. There are also correlations for loam and clay soils. This strategy enables tests to be carried out more quickly and at a lower analytical cost. One benefit of using the 1:2.5 soil:water suspension is that it can also be used to measure pH; furthermore, it is the one that yields the smallest error in the calculation of the Potassium. However, the greatest accuracy will be provided by the saturated soil test itself.