Top soil is the upper layer of soil, this soil has the highest concentration of organic matter and microorganisms and it is where plants concentrate their roots in and obtain most of their nutrients. The top soil is very important so we need to minimise plowing, tilling and digging. Every time the soil is tilled, surface – layer organisms are buried, threads of beneficial fungi are broken and earthworm tunnels are destroyed, plowing can bury plant debris and top soil up to 14 inches deep, where oxygen levels are too low for decomposition.
The soil microorganisms do much more than nourish plants, soil microorganisms digest nutrients and protect plants against pathogens and other threats. The living soil is the Earth’s most valuable ecosystem, providing ecological services such as climate regulation, mitigation of drought and floods, soil erosion prevention and water filtration.
To add nutrients to top soil we can use compost, grass clippings, leaves, and other organic mulches on a regular basis to promote and sustain the soil food web. Always keep the soil covered with live crops, or an organic mulch. Whenever we are not growing a food crop, sow a cover crop, so the carbohydrates pipeline is not shut off. Mother Nature never leaves the soil uncovered, “only on farms and gardens do we see naked soil“, leaving the soil bare shuts off the carbohydrate food supply, and lack of moisture and ultraviolet rays kill some of the organisms that dwell in the surface layer as well.
A good idea is to make permanent beds that are 4 feet across so all work can be done from the sides without having to ever step on the soil. It is essential to leave the roots in the ground after harvests giving food and shelter to microbes and earthworms.
Subsoil is the layer of soil under the topsoil, it is composed of a variable mixture of small particles such as sand, silt and or clay, but it lacks the organic matter and humus content of topsoil. There are simple test to help determine your soil type: the water test, the squeeze test, settle test and acid test. Adding ground lime to your soil will make it more alkaline, and aluminium sulfate or sulfur will help to make your soil more acidic. Rock phosphate or rock dust is also a valued amendment to restore phosphorus levels needed for vigorous plant growth.
Clay soil feels lumpy and it is sticky when wet and rock hard when dry. Clay soil is poor at draining and has few air spaces, so it is ideal for water retention and natural made ponds, lakes, etc. This soil will warm up in spring making it heavy to cultivate. Clay soil can be very rich in nutrients, if the drainage of the soil is enhanced, plants will develop and grow well. Clay soil is great for growing perennials and shrubs such as fruit trees, ornamental trees, and summer crop vegetables giving high yielding vigorous plants; early vegetable crops and soft berry crops can be difficult to grow because of clay soil cool and compact nature.
Sandy soil feels gritty, it drains easily, dries out fast but it is easy to cultivate. Because sandy soil warms up fast in spring you can sow early seeds outside, but it requires organic amendments as it tends to hold fewer nutrients than other soils as these are often washed away during wetter spells. Adding glacial rock dust which contains a broad range of trace minerals and promotes long-term soil vitality and healthy plant development are a must for sandy soils. Also you can add greensand which is a long-term soil amendment that regulates moisture content to increase soil fertility; another option is adding kelp meal to provide potassium and trace minerals to sandy soil and plants, this is recommended as well as any other organic fertilizers blends which are loaded with minerals and nutrients. This soil also benefits from mulching to help retain moisture and prevent water from drying out too fast. Sandy soil is great for growing vegetable root crops like carrots, parsnips and potatoes. Lettuce, strawberries, peppers, corn, squash zucchini, collard greens and tomatoes are grown commercially in sandy soils.
Silty soil feels soft and soapy, it holds moisture, is usually very rich in nutrients. This soil is easily cultivated and can be compacted with little effort. This is a great soil if drainage is provided and managed, mixing in composted organic matter is usually needed to improve drainage and structure, while adding important nutrients. This soil is great for growing shrubs, climbers, grasses, perennials, most vegetables and fruits crops thrive in silty soils.
Peaty soil is a darker soil and it feels damp and spongy due to its higher levels of peat. It is an acidic soil having fewer nutrients. Drainage channels may need to be dug for soils with high peat content. It is a great soil when blended with rich organic matter, compost and lime to reduce the acidity. Peaty soil is great for growing vegetable crops such as brassicas and legumes; root crops and salad crops will do well in well-drained peaty soils.
Chalky soil is larger grained and generally stonier compared to other soils. It is free draining and usually overlays chalk or limestone bedrock. The soil is alkaline in nature which sometimes leads to stunted growth and yellowish leaves. This can be resolved by using appropriate fertilizers and balancing the pH. Adding humus is recommended to improve water retention and workability. Chalky soil is great for growing vegetables such as spinach, beets, sweet corn and cabbages.
Loamy soil is a relative mix of sand, silt and clay; it feels fine-textured and slightly damp. It has ideal characteristics for gardening,lawns and shrubs. This soil has great structure, adequate drainage, is moisture retaining and full of nutrients, easily cultivated warming up quickly in spring, but doesn’t dry out quickly in summer. Loamy soils require replenishing with organic matter regularly and tend to be acidic; rotating crops, planting green manure crops, using mulches, and adding compost and organic nutrients is essential to retain soil vitality. loamy soil is great for growing most vegetables, berry crops, perennials, shrubs and climbers.