BIOL 2140 Lecture Notes - Lecture 3: Dimeter, Permanent Wilting Point, Field Capacity
Document Summary
Soil nutrients: plants need oxygen, carbon, and hydrogen to fuel survival and growth. Plants also require other inorganic nutrients including nitrogen, phosphorus, calcium, and potassium to make proteins, nucleic acids, and other essential compounds. Many nutrients are obtained as ions dissolved in water held by soil. Water potential: a measure of water"s potential energy; affects the movement of water in soil from one location to another. Matric (or matrix) potential: the potential energy generated by the attractive forces between water molecules and soil particles; occurs because water molecules and soil particles have electrical charges. Matric potential is quantified in units of pressure, called megapascals (mpa) In saturated soil, most water does not contract soil particles and is not strongly held by the soil; matric potential 0 mpa. When gravity drains the water in soil, the matric potential drops to 0. 01. The max amount of water held by soil against the force of gravity is the field capacity of the soil.
