Agriculture Reference
In-Depth Information
a continuous flow of water to streams, making their application for agricultural
purposes limited. Basso (2000) created a spatial soil water balance model called
SALUS-TERRAE that accounts for water pooling in depressions, surface and sub-
surface water movements, and the water runoff-runon mechanism occurring on
the landscape. SALUS-TERRAE was developed by coupling the Ritchie vertical-
soil-water balance model (Ritchie 1998) with TERRAE, a digital terrain model
developed by Gallant and Basso (2013). SALUS-TERRAE is a spatial soil water
balance model composed of vertical and lateral components of the water balance.
The model requires a digital elevation map for partitioning the landscape into a
series of interconnected irregular elements. Weather and soil information for the
soil water balance simulation is also needed.
SALUS-TERRAE has been applied at a location in Michigan similar to the KBS
LTER. Figure 10.3 shows the spatial variability of soil water content across the
landscape the day after a rainfall event of 65 mm. SALUS-TERRAE was able to
simulate the higher surface ponding capacities in the depression areas. The model
performed well when compared to field measurements of soil water content for
the entire growing season (Fig. 10.4): the root mean square error (RMSE) between
measured and simulated results varied from 0.22 cm to 0.68 cm (Basso 2000,
Batchelor et al. 2002). The net surface flow (Fig. 10.5) is the difference between the
amount of water leaving each element (runoff) from that running onto the element
(runon). The highest value (-5 cm) is observed at summit positions in the landscape
since these elements do not have any water running into them. Application of the
SALUS-TERRAE model can benefit precision agriculture by being able to select
the appropriate management strategy for optimizing management practices across
the landscape.
Figure 10.3
. Simulated kriged map of soil water content (cm) for the surface (0-26 cm)
soil layer using the digital terrain model SALUS-TERRAE in a sandy loam soil in Durand,
Michigan. Redrawn from Basso (2000).
