Field capacity

The moisture condition where a soil contains the maximum amount of water that it can hold against gravity, and where further wetting will result in drainage. Following saturation, soils typically return to field capacity, when the rate of downward movement of water has substantially decreased, usually 1-3 days after rain or irrigation after the gravitational, or free, water has drained away. It is typically expressed as a mass or volume fraction of soil water or as a soil moisture deficit (SMD) of zero. It is the water content retained at low suctions (5-33kPa) depending on soil type, and is the upper limit of plant available water.