Cycle of water in the soils with Bargic horizons [articol]

Abstract

The amount of moisture stored in the soil and available to the crop can be inferred from determinations of soil texture, structure and porosity, or measured directly by pF curve determinations. When water is added to the soil by rain or irrigation, the soil surface becomes saturated, and the water travels downwards under gravity and capillarity, i.e. drainage takes place. The amount of moisture stored in the soil and available for plants can be measured directly by pF curve determinations. An argic horizon is a subsurface horizon with distinctly higher clay content than the overlying horizon. The Romanian Soil Taxonomy System (SRTS - 2012) contains soil types with B argic horizons, as follows: Preluvosol, Luvosol, Planosol, Alosol, and Stagnosol. For low suction values, samples are placed on a porous plate, saturated with water. Suction is applied by lowering the water level in the manometer. For high suction values, samples are equilibrated in pressure plate extractors. For practical use it is necessary to know the amount of water which can be depleted before these suctions are reached. On the base of data, presented were calculated the curve suction – moisture content for a Stagnic – albic Luvisols from Lalasint. The suction – moisture curves allow to establish the irrigation requirement, leaching requirement, deep loosening requirement, the moisture reserve.