BIO-8 Lecture Notes - Lecture 29: Permanent Wilting Point, Water Potential, Field Capacity
Document Summary
Most terrestrial plants obtain nutrients and water from the soil. Many nutrients obtained as ions dissolved in water (ammonium, nitrate, phosphate, calcium) availability. Water potential - a measure of the water"s potential energy. Matric (aka matrix potential) - the potential energy generated by the attractive forces between water molecules and soil particles. It exists because water molecules, which have electrical charges, are attracted to the surfaces of soil particles, which also have electrical charges. This attraction explains why soil is able to retain water against the downward pull of gravity. Soil composition affects field capacity and wilting point (point at which plants can no longer retrieve water from soil) Scientists refer to a water potential of 1. 5 mpa as the wilting point of soil - lowest water potential at which most plants can obtain water from the soil. Silt loam soil - a soil containing a higher proportion of silt and a lower proportion of sand.
