THE SOIL ELEMENT
Cutting a deep vertical slice out of your lawn will reveal at least two soil layers with different colours and textures.
- The top layer called topsoil contains more organic matter, usually making it darker and looser than the deeper layers.
- The lower layer called subsoil is lighter colour and is often hard and poor in nutrients.
Soil is composed of mineral particles and organic material. The texture of your soil depends on the proportion and distribution of mineral particles like sand, silt, and clay, from the largest to smallest.
The best soil is a loamy soil containing all three particle sizes in ideal proportions.
- A sandy loam supports plant growth the best.
- Loam naturally contains a good proportion of air spaces.
- Loam also absorbs water easily and quickly, yet allows water, air, nutrients and organisms to circulate freely and roots to penetrate easily.
Take a handful of moist soil and squeeze it into a ball.
- Sandy soil doesn’t hold its shape when pressed.
- Clay soil forms a lump that holds its shape.
- Loam forms a ball of soil but breaks easily.
The pH represents the level of acidity or alkalinity of your soil. Soil pH is measured on a scale of 0 to 14 with values below 7 being acidic, those above 7 being alkaline and 7 being neutral.
- Slightly acidic soil (pH 6.0 to 6.5) allows the soil to release the optimum amount of nutrients.
- Acidic soils are typically found in areas of high rainfall. Lime can be applied to raise the pH.
- Soil can also be too alkaline, especially where the bedrock is limestone. Sulphur can be added to lower the pH.
THE SOIL ENVIRONMENT
The soil is home to a large number of insects, spiders, mites, worms and microorganisms. All of these organisms form the soil’s food-web and play an important role in maintaining soil health and in supporting plant growth.
Soil organisms benefit your lawn.
- They decompose lawn clippings and thatch.
- They help mix organic material with mineral matter throughout the soil, while creating pockets and channels for water and air to move.
- They digest organic material, helping to provide nutrients to plants and retaining nutrients in the root zone.
Lawn maintenance practices affect more than just the grass on the surface.
Avoid excessive watering as the water fills up air spaces and reduces the oxygen supply to the soil. Avoid over fertilizing as it disrupts the nutrient balance and may decrease the amount of organisms in the soil. Reduce or eliminate the use of pesticides to protect beneficial insects and earthworms.
Grass consists of leaves, stems and roots like other plants.
- Blades of grass are leaves that extend out of a sheath at the base where they wrap around the plant stem.
- The stem and blades grow upwards from a crown found at or near the soil surface. The is how grass withstands repeated mowing.
- A grass plant can recover when it loses roots, leaves or stems, but not when the crown dies.
- A dense, deep root system is important to support top growth in grass.
Grasses reproduce by seed and by stolons (above-ground lateral stems) or rhizomes (underground lateral stems). They also form new shoots known as tillers that are attached to the original plant and add to the fullness of the lawn.
PLANTS FOR BIODIVERSITY
Promote biodiversity in your yard by including a variety of plants and grass species in the landscape. A diverse landscape is better for the environment because it attracts birds, butterflies and other wildlife. It can be easier to maintain when the right plants are chosen to suit the conditions.
Just like in the soil, a good diversity of organisms in the landscape supports a healthier plant environment.
- Consider other plants that can make good ground covers, especially for shaded, dry or other difficult sites. Some of these are hosta, lily of the valley, creeping phlox, Japanese spurge, periwinkle, bugleweed, sweet woodruff, thyme and creeping juniper.
Experiment with native plants amd alternative landscapes such as mulched perennial beds or rock gardens. These are drought resistant and require less maintenance.
Fungi known as endophytes grow inside certain grass species, but do not harm them. Grasses containing endophytes are more resistant to certain insects because the fungi produce alkaloids that act as a toxin.
Many beneficial insects live in and around your lawn and you need to make sure they are not harmed. There are four categories on beneficial insects:
- Predators like ladybugs, praying mantises, lacewing, dragonflies, and ground beetles feed on other insects.
- Parasitic insects are usually tiny wasps or flies that live in or on pest insects.
- Pollinators play an essential role in plant reproduction while feeding on nectar or pollen. These include bees, butterflies, and moths.
- Soil0dwelling insects are vital for many aspects of healthy soil.