Neeshia Macanowicz-Soil Moisture in the Desert 7/24/2019
Neeshia Macanowicz, restoration ecologist at Jornada Experimenta Range, reviewed how to measure soil moisture. As part of a larger project, Neeshia is collecting soil moisture data on 36 plots in Jornada in the Chihuahua Desert. 36 plots are evenly distributed, 12 plots each in Heigma grassland, shrub-grass mixed and shrub ecological status. Other researchers at Neeshia and Jornada wanted to know whether there are detectable differences in soil moisture between three different plant community types (ecological states). Here, Neeshia explained the working principle of the soil moisture probe and what it measures: the speed at which water penetrates 10 cm (the depth at which the probe is installed) after a heavy rain event, and the speed at which the soil dries out after the rain ceases. If there are detectable differences in soil moisture between the three types of plant communities, this may be one of the factors affecting their ability to grow grass. Soil moisture affects seed germination and plant growth. The surface of the soil must be moistened long enough for new seeds to germinate. Then the moisture in the upper 10 cm of the soil profile must exist long enough for the seedlings to establish. Longer soils can hold water within the upper 30-50 cm, and the longer the existing perennial grasses can use the water. The faster the water infiltrates, the faster the upper soil depth will dry out, the harder it is for grass seeds to germinate, and the harder it is for grass plants to grow. However, shrubs, such as honey mesquite, can easily use soil moisture at lower depths (for example, less than 50 cm, where grass roots are usually not found). Soil moisture data and other data will provide a more reliable understanding of the processes affecting the three vegetation states. The data collected by Neeshia and other scientists provided information about the potential of 36 plots to grow plants, preserve resources, and resist erosion. These data include: soil profile description (soil texture and other characteristics), permeability, soil stability, and plant coverage of different species. Jornada also has a weather station that monitors wind speed, precipitation, wind-borne sediments and other variables. .