Improvement of Salt-affected Soils, Part 1: Interception of Capillarity

On other hand, in the pseudogley soil cylinder with the coarse layer (our proposed treatment), the pH values of the horizon above the coarse layer decreased gradually after repeated application of simulated rainfall, and there was no increase of pH value upon addition of a Na2CO3 solution. About 3900 mm rainfall (six and a half years' supply) was required to get a pH value of 7·5 in every horizons. The minimum measured soil water content was 17·6% d.b. at the soil surface, and the soil water content of the C horizon below the coarse layer was constant at about 60% d.b. The EC values at the soil surface, the Ap and B horizons above the coarse layer had small fluctuation and converged 50 mS m−1. The EC value at the C horizon below the coarse layer varied sharply the same as that of the pseudogley soil cylinder without the coarse layer.