Now that the crush is over vineyard managers can turn their attention to planting cover crops and laying straw to protect exposed dirt from the rains we will be getting soon.
Alice Outwater, in her book Water – a Natural History, states that without the protection of leaves or straw rain strikes the soil “like little bombs,” turning dirt “into a pasty mud that clogs the pores and passages in the soil… The runoff sweeps along tons of topsoil, gravel, and stones, and dumps the spoils into the waterways…” reducing the fertility and health of the soil.
Spreading a 4 -inch layer of mulch promotes soil fungus which increases the porosity of soils so the water can stay close to the plants and vineyard managers know that root tips need fungus in order to absorb the nutrients in the soil.
I’d like to encourage those laying out straw to consider taking cuttings of willow when the trees go dormant. The cuttings should be ½ to 2 inches in diameter and 3 feet long, soak them in water for 48 hours then hammer them into the streambanks when the soil is moist. This will help slow the force of the streams and reduce the water’s erosive effects. Depending on the extent of your willow planting you may need a permit from the California Department of Fish and Wildlife (CDFW). The CDFW regional office phone number is (707) 944-5500.
Willows provide food and building materials for beaver which are a keystone species in an environment and were historically more common in this area. The water behind their dams and lodges provides an environment for phytoplankton, zooplankton, Steelhead fry, frogs and the critters that eat those creatures. The height of the water behind dams can be controlled so flooding is less of an issue, for example, flow devices called Beaver Deceivers can be installed to keep a pond at a safe, consistent height; and the trunks of ornamental trees can be wrapped in welded wire mesh for protection.
Groundwater recharges along stream banks which is why it’s important to slow the water down and make sure it can percolate through the soil. Who knows, perhaps the – as yet unformed – Sonoma Valley Groundwater Sustainability Agency will provide you special dispensation if you have a beaver dam on your property engaged in groundwater recharge. Fortunately, beaver don’t need permits for the beneficial work they do in the creeks.
For more information contact your local Resource Conservation District (RCD) office, which in our area is the Sonoma RCD in Santa Rosa (707) 569-1448.
P.S. This letter was proofread and approved by employees of the Sonoma Ecology Center, the Sonoma Resource Conservation District and the California Fish and Wildlife Department.