University of Florida


Evaluation of Minimal Required Number of Soil Moisture Sensors for Uniform Agricultural and Turfgrass Irrigation Control

Sponsor: Southwest Florida Water Management District

Timeline: 1/25/2010 – 8/31/2012


Agricultural water use is the largest single category of water use in Florida. According to USDA, there are 3.7 million acres of crop land in Florida and, in 2003, 49% of this land was irrigated and 62% of harvested crop land was irrigated in the same year. Frequent occurrence of drought conditions associated to the large use of water by municipal, agricultural and industrial purposes has been increased the needs of implementation of more efficient irrigation systems.

Recently, SWFWMD and FDACS have funded multi-year projects to investigate the potential use of soil moisture based irrigation for vegetable production and landscape applications. The use of soil moisture sensors has shown strong potential for saving of irrigation water in experimental plots. This type of control system has been successfully used on sweet corn, green bell pepper, zucchini, tomato, turfgrass and is currently being used with promising results on golf course fairway irrigation control.

The expansion of the use of soil moisture sensor technology to control and monitor irrigation in large areas requires a more detailed study of soil moisture in the upper soil layer. The variance of soil moisture spatial patterns is expected to be dominated by soil type, topography and vegetation. In addition, the characterization of soil moisture variability can be related to the topographical attributes such as slope, elevation, and distance from the drainage channel. This information is crucial to a successfully implementation of soil moisture sensor system especially for areas susceptible to flooding or with high water infiltration rates. The number of soil moisture sensors needed to effectively control irrigation or monitor soil in cropped areas is still unknown. This project will investigate the spatial variability of soil moisture in irrigated agricultural with potential for use of soil moisture sensor irrigation in relation to topography and soil properties and will also address the issue concerning the minimum spot measurements or/points for soil moisture sensor location number to estimate the representative water content in a given field area.