As we kick off our first week of summer at MNBP, we are also kicking off the start of the new Soil Solarization trial. Most people have probably never heard of soil solarization but it’s a fairly simple process that could change the way farmers, land managers, and gardeners control weeds and invasive species.
Soil Solarization is a hydrothermal process the greatly heats up moist, exposed soil during the summer months due to the use of a plastic covering to intensify the sun’s rays. If the soil remains at a temperature of 99° F for 2-4 weeks it can almost completely eliminate the emergence of many annual weeds and invasive species. Some researchers believe that this process is more effective than spraying herbicide because the intense heat can penetrate deeper into the soil to burn up any weed seeds, while herbicide spraying only targets the above-ground problem. Soil solarization is also safer for the environment and less expensive than spraying.
Tests have also shown that soil solarization can also increase the availability of essential nutrients such as, nitrogen, calcium, magnesium, phosphorus, and potassium!
So to test the effectiveness of the soil solarization we are setting up our own plots to hold our own trial. Last week (while I was at the Conway) Courtney, Giselle, and Isabela flagged 3 separate 25’x50’ plots in a field that needs to be converted back to grassland after being overrun by invasive species; 1plot for soil solarization, 1 plot for herbicide spraying, and 1 plot for the control.
Soil Solarization is a hydrothermal process the greatly heats up moist, exposed soil during the summer months due to the use of a plastic covering to intensify the sun’s rays. If the soil remains at a temperature of 99° F for 2-4 weeks it can almost completely eliminate the emergence of many annual weeds and invasive species. Some researchers believe that this process is more effective than spraying herbicide because the intense heat can penetrate deeper into the soil to burn up any weed seeds, while herbicide spraying only targets the above-ground problem. Soil solarization is also safer for the environment and less expensive than spraying.
Tests have also shown that soil solarization can also increase the availability of essential nutrients such as, nitrogen, calcium, magnesium, phosphorus, and potassium!
So to test the effectiveness of the soil solarization we are setting up our own plots to hold our own trial. Last week (while I was at the Conway) Courtney, Giselle, and Isabela flagged 3 separate 25’x50’ plots in a field that needs to be converted back to grassland after being overrun by invasive species; 1plot for soil solarization, 1 plot for herbicide spraying, and 1 plot for the control.
Yesterday we conducted vegetation surveys to determine what species were present in our plots and how much space they covered. We placed a 2’x2’ wooden frame in six places within each plot and then recorded the different species within the frame. Overall, there was quite a bit of autumn olive (Elaeagnus umbellata Thunb.) and lespebeza (Lespedeza sp.), both of which are invasive. After the trial is done we will redo the surveys and use the difference in results to compare the effectiveness of each method.
Today we used a soil probe to collect five, 6” soil cores from each plot to send to the Soil Testing Lab at Virginia Tech. The lab will run analysis on pH and several other macronutrients including, phosphorous, potassium, calcium, copper, and iron. After the trial is over we will send more soil cores to VT to determine if there is any difference in the availability of soil nutrients.
I think this study is absolutely fascinating and can’t wait to see what the results show. Based on what we find, soil solarization could make an interesting impact on the agriculture and natural resources industries.