Howdoes soil help stormwater?
Healthy soils help support plant growth, prevent erosion, and filter out pollutants. Poor soil is compact and lacks organicmatter.
In fact, organicmatter in soil filters out pollution from road runoff which can be toxic to salmon. Healthy soil is a low techway to
manage stormwater by helping filter and storewater. Soil quality is directly related to the health of streams and other bodies of
water in the PacificNorthwest.
What is soil?
Soil ismade up of decomposing rock, minerals, organicmatter,
air andwater. Mineral particles – otherwise known as “dirt” –
come in different sizes:
• Mineral particles come indifferent sizes:
Sand:
Largeparticleswith lots of space for air andwater,
but can’t holdontomuchwater or nutrients for plants
Silt:
Mediumparticles
Clay:
Tinyparticles that stick together. Clay can hold
onto a lot of nutrients, but it’s hard for air andwater to
penetrate it.
• Organicmatter ismade upof all thebillions of soil organisms
plus thedeaddecayingmaterial that they eat. Healthy soil
acts as an ecosystem, or a living community of anorganism,
which sustains plants, animals and humans.
• Air andwater – about half the volume of healthy soil is space
that canbe filledby air andwater.
Howdoes healthy soil helpfish?
Healthy soil can help to slow the flow of stormwater runoff and
filter pollutants out of thewater. In addition, heathy soilswill
absorbmorewater. This increases the volume of groundwater
we have – a source for cool water to our creeks during our dry
summers.
Composting helps build healthy soil:
Compost improves all soils. It helps sandy soils hold nutrients
andwater, and loosens clay soils for air andwater to penetrate.
Compost feeds the beneficial soil microorganisms, so it can feed
andprotect your plants. Lay on top, dig, or rototill in 1-3 inches
of compost when you’remaking newbeds or planting lawns.
Try it out! Make your own compost bin!
Leaves, chopped stalks, flowers andgrass all make great
compost in a pile or bin – just addwater, keep itmoist, andwait
sixmonths. Vegetable kitchen scraps alsomake good compost,
but shouldbe composted in awormbin or other rodent-
resistant container to prevent pest problems.
There aremany different ways of composting, and other things
you can do (such as addingworms) to speed up the process.
Research some of these ideas on your own and try them out on
your compost bin!
Mulch is another way to keep your soil healthy
!
“Mulch” is a layer of organicmaterial like leaves, wood chips,
compost or grass clippings that you spread in spring or fall
around your plants. (Keep it about an inch away from stems.)
Mulch conserveswater by keeping the soil moist, preventsweed
growth and erosion, and replenishes organicmaterial in the soil
for healthier plants.
Mulch improves:
• Flower beds and vegetablegardens: Use 1-3 inches of leaves,
compost or grass clippings.
• Trees, shrubs andwoodyperennials: Use 2-4 inches of woody
mulches, likewood chips (get from a tree service) or bark. Fall
leaves alsoworkwell.
• Lawns: Mulch your lawn?Yes, you can “grasscycle” (leave the
clippings) and spread compost.
Soil is alive!
Four billion organisms live
in a teaspoon of healthy soil.
Imaginewhat’s in your yard!
These beneficial organisms,
such as bacteria and fungi, live
around each plant root. They
convert decayingmaterials into
energy and essential nutrients
for plants. Earthworms and
millipedes tunnel their way
through soil, making space for
air andwater
Resources:
your.kingcounty.gov/solidwaste/naturalyardcare/functions.asp
fungi
millipede
earthworm
bacteria
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| SUNDAY,
OCTOBER30, 2016
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