Ground Cover is Good
The core of the active demonstration is a rain simulator, which uses a rotating spray to realistically simulate Southwest rain conditions (large, fast-moving raindrops). The "rain" falls on up to 5 different types of soil cover conditions, ranging from bare dirt to thick vegetative cover such as sod, and the runoff from each sample type is collected in a clear jar. All the samples have the same soil under the cover, that being typical New Mexico soil which is dominated by clay and sand and which has little organic content. The key difference in each sample is the amount of cover, which the simulation then shows makes a dramatic difference in the amount of water and soil retained during a rain. The "rain" falls for approximately 3 minutes, and the runoff collection jars then show and prove just how dramatic a difference there is, in quantity and in quality, of runoff from the different samples. While many people believe bare dirt will "hold" the most rainfall, the simulator shows that the opposite is actually the case, as bare dirt "holds" the least rainfall and causes the largest amount of runoff by volume and by soil carried away. This then shows how critical good ground cover is to land health.