By Lynn Wunderlich
Greetings Fodder Folks! With the heavy deluge of rain we've been experiencing, some of you may have noticed signs of soil erosion from our precious foothill slopes. While some conservation techniques require pre-planning and assistance, it is not too late to implement some of these soil conservation practices. The first step is to understand your soil and it's erodibility, described here by UC Soil Scientist Toby O'Geen. Here are some tips for preventing the loss of soil, now and in the future:
Erosion of soil like this can be prevented!
1. Straw mulch. Straw mulch is a relatively simple way to hold your precious soil in place. Rice straw is particularly desirable because it has fewer weed seeds, but it is also high in silica which doesn't break down quickly and can actually tie up nitrogen. To remedy this, applications of nitrogen (no more than 1500 lbs. per acre, applied AFTER the rainy
season) are recommended.
Straw mulch is a simple way to hold soil in place.
Straw from upland grains (oats, barley and wheat) breaks down more quickly than rice straw but may contain noxious weed seeds. Make sure you know your source! Information on where to obtain weed free forage is available here from the Cal-IPC (Invasive Plant Council) site. Seeding rate is 1500-3000 lbs./acre. See this Straw Mulching Info. Sheet from Napa County RCD.
2. Straw Bale Wattles are a low-cost, effective way of diverting run-off; often used after fire.
Straw Bale Wattles can be placed strategically within a slope.
3. Diversions. Diversions require planning and construction-so take note of where you think an installation would be helpful. They can be used to break up concentrations of water runoff on long slopes, diverting it to a safe and stable outlet.
4. Rock dam. Check dams can reduce the velocity of flow at the base of a slope.
5. Cover crops. Cover crops have many benefits, including holding valuable soil in place. One of the most important issues with cover crops that I see in the foothills is managing them at the right time (that's just about now, or at vine and tree budbreak).
Cover crops can improve soil-but need to be managed in a timely manner.