jordvätskespänningen

Jordvätskespänningen, often translated as soil moisture tension or soil matric potential, is a measure of the energy with which water is held within the soil. It is a key concept in soil science and hydrology, indicating how tightly soil particles are attracting water molecules. When the soil is dry, the forces holding water to the soil particles are strong, resulting in a high soil moisture tension. As the soil becomes wetter, these forces decrease, and the soil moisture tension becomes lower, approaching zero when the soil is saturated.

This tension is primarily due to capillary forces and adsorptive forces. Capillary forces arise from the surface tension of water within the small pores of the soil. Adsorptive forces are the attraction between water molecules and the solid surfaces of soil particles. Soil moisture tension is typically measured in units of pressure, such as kilopascals (kPa) or centibars (cb).

Understanding soil moisture tension is crucial for various applications. In agriculture, it helps determine irrigation needs, as plants can only extract water from the soil if the soil moisture tension is below a certain threshold. In environmental science, it influences groundwater recharge, runoff, and the movement of pollutants through the soil profile. Different soil textures exhibit different soil moisture tension characteristics; for instance, sandy soils tend to have lower soil moisture tension at lower water contents compared to clayey soils, meaning water drains more readily from sand.