We conducted a laboratory experiment on the interrelationships among five rates, it (0 to 1.6%), of a gel-forming conditioner (Jalma—containing 24.5% humic acids and 3.8% polysaccharides), water penetrability (Λ), weighted-mean diffusivity (λ), swelling index (S), and effective mean pore radius (λ) of a loamy sand, a sandy loam, and a loam. For each of the three soils, the results indicated a highly significant linear increase in S and a consequent exponential decrease in r, λ, and D with increase of R. The effects of Jalma on these parameters were more marked on the loamy sand than on the other two soil samples.
Addition of 0.2,0.4,0.8, and 1.6% Jalma to the loamy sand sample significantly reduced Λ by about 19, 55, 83, and 98%, respectively, and D by about 38, 76, 96, and 100%, respectiely. The highest rate almost completely sealed the soil independent of its texture and reduced D to almost zero. We concluded that 0.4% Jalma is the optimum rate for soil water conservation. We argue that Jalma addition causes swelling of the soil matrix, reduces the effective mean pore radius, and consequently reduces Λ and D. The effective mean pore radius proved to be a reliable predictor of D and Λ of the soil samples studied independent of their texture: Λ = 2.548r0.49 (r2 = 0.960), and D = 3.303r1.075 (r2 = 0.958).
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