Automatic in situ determination of field capacity using soil moisture sensors

• Published in: Irrigation and drainage Vol. 61; no. 3; pp. 416 - 424
• Main Authors: Fazackerley, Scott, Lawrence, Ramon
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.07.2012
• Subjects: automation; automatisation; capacité au champ; drainage; field capacity; gravity; irrigation; irrigation scheduling; irrigation systems; landscaping; monitoring; prediction; sensors; soil profiles; soil water; water content; water use
• ISSN: 1531-0353; 1531-0361
• DOI: 10.1002/ird.646

Field capacity is a frequently used concept in irrigation systems and agriculture. Although there is some debate on how field capacity is defined, it is generally accepted as being the upper limit on the available water that is stored in a soil profile that can be held against the pull of gravity. Standard methods for determining field capacity require waiting two days before measuring volumetric water content after raising the water content above field capacity. This is time‐consuming and subject to natural water inputs during the monitoring period. The contribution of this work is a method for rapidly estimating field capacity in situ using volumetric water sensors, a specific irrigation schedule, and a nonlinear curve fitting model that predicts field capacity using a drainage model. The result allows for determining field capacity rapidly with very good accuracy and can be used with automatic irrigation systems in landscaping and agriculture.