Analysis of soil water availability by integrating spatial and temporal sensor-based data

An efficient irrigation system should meet crop demands for water. A limited water supply may result in reductions in yield, while excess irrigation is a waste of resources. To investigate water availability throughout the growing season, on-the-go sensing technologies (field elevation and apparent electrical conductivity) were used to analyze the spatial variability of soil relevant to its water-holding capacity. High-density data layers were used to identify strategic sites to monitor changes in plant-available water over time. To illustrate this approach, nine locations in a 37-ha agricultural field were selected for monitoring the soil matric potential and temperature at four depths (18, 48, 79 and 109 cm) using wireless technology. Using a linear regression approach, a field-specific model was developed that quantified plant-available water at every field location and at specific points in time. Further analysis was used to quantify the percentage of the field that undergoes a potential shortage in water supply. These results could be used to optimize irrigation scheduling and to assess the potential for variable-rate irrigation.