Abstract |
The proximity of a water table to the soil surface supplies water for evaporation and indirectly, controls the rate at which salt can accumulate at the surface. A water table was established at two depths, 60 cm. and 120 cm., in lysimeters made with undisturbed cores of Biotia silt loam. The water table level in the lysimeters was automatically controlled, evaporation rate was measured, and changes in soil salinity were determined. A cover kept rainfall off the lysimeters and permitted study of salt distribution under separate evaporation and leaching conditions. During the study, lysimeters with a water table of 60 cm. evaporated approximately twice as much water as the lysimeters with a water table at 120 cm. Salt accumulation increased with increasing amount of water evaporated. The level of salinity reached in most lysimeters in the surface soil layer would have seriously decreased seed germination and growth of many plants of agricultural significance. (Author) |