A QUICK LOOK AT YOUR SOIL

Today we are going to talk about the soil. The ideal soil should be about 65 percent mineral particles, 25 percent air and water and 10 percent organic matter. It should have a structure that allows excess water to drain leaving adequate soil moisture, provide proper aeration for the roots, hold nutrients in a form available to the plants, and be the proper pH for the plants you wish to grow. Very few places have the ideal soil but you can modify your existing soil to meet the needs of your planned landscape. If you are planning perennial beds, lawn and other permanent landscaping, you must make your modifications before you plant as it is difficult to add large amounts of organic matter or other additives without disturbing the roots of perennial plants. Beds for annuals type plants can be improved over time as they are dug every year. When you are creating a new landscape, you should not be in a hurry to plant. Take the time to improve your soil. Annuals flowers and grasses can improve the looks of your property in the meantime.

The soil is a complex entity made up a minerals, organic material in varying stages of decay, micro-organisms and macro-organisms. Together they determine the ability of the soil to provide nutrients, air and water to the plants. We will cover each of these factors more thoroughly as we go.

The first thing you need to do is determine what your soil type is. Often, just by looking at and feeling it you can tell if it is very sandy, heavy clay or has lots of fibre. Also look at the type of natural vegetation, for example pines indicate a dry, well drained, sandy soil and willows signify a wet soil.

If it is very sandy, water will drain out too quickly leaching valuable nutrients with it. Very few plants will grow in this type of soil. This soil needs the application of organic matter such as manure or compost to improve its water holding capability. If your soil is heavy clay, organic matter will improve its workability preventing it from becoming cement in the dry weather and improve drainage of excess water. Clay soil has the potential to be high in nutrients but that will be of little use to your plants if they cannot put their roots down into the soil.

Next you should determine what nutrients are presently in your soil as well as its pH. Plants require a certain range of pH to be able to grow and be healthy. Some, like pines, need acidic soil. Other might require the addition of lime to their soil. Soil testing kits are available at most seed suppliers and are relatively inexpensive. Although not as accurate as professional tests, they are adequate for most home applications.

Do not think that all you have to do is dump fertilizer onto whatever soil you have and that will ensure an abundant crop. All the fertilizer in the world is no good if it is locked up in the soil and cannot be absorbed by the plants roots. Or your ground becomes as hard as your sidewalk in summer and like a swimming pool during the rainy season. Plants do not know the difference between nutrients derived from commercial fertilizer or organic matter. Plants can only use nutrients in their chemical form but material such as compost does more than just provide fertilizer.

THE EFFECT OF PH IN SOIL

Some plants that prefer acid soil (pH 4.5 to 5.5) are blueberry, cranberry, azalea, rhododendrom. Some plants that require moderate acidity (5.0 to 6.0) are potatoes, sweet potatoes, watermelon and roses. Generally most vegetables and flowers do well in a range of 6.0 to 7.0

Prairie soil is generally alkaline, although there are areas where the soil is acidic such as high peat areas. If the pH of your soil is too low, it can be adjusted by the addition of ground limestone. Dolomitic lime not only raises the pH but also supplys calcium and magnesium to the soil. To lower the pH of the soil, iron sulphate or aluminum sulphate may be used. Sulphur has a long term effect on pH but is slower and it is costly. The best method is to add humus to your soil which increases the acidity as it breaks down and select a fertiizer that has an acidic base such as ammonium nitrate or ammonium sulphate which tend to acidify the soil Calcium nitrate and sodium nitrate have the opposite effect. Some such as super- phosphate are neutral and do not change the pH of your soil.

Soil salinity becomes a problem where there is poor subsoil drainage and high evaporation. If the concentration of soluble salts becomes too high, plants can look like they are suffering from lack of water when in fact there is sufficient moisture present. This is because the water leaves the root instead of entering it. This can be corrected by the application of humus to the soil. Also leaching the salts to below root level with heavy waterings will help. The salts present in saline soils are usually magnesium sulphate (Epsom Salts) and sodium sulphate (Glauber Salt). Epsom salt is used by some gardeners to discourage root maggots. Before using it, have your soil tested to ensure that there is not already excess salts. Also avoid high applications of inorganic fertilizers. Fertilize at lesser rates more often to avoid increasing the salinity of the soil.

ORGANIC MATTER IN THE SOIL

Organic matter can be decomposing plant material, animals, animal wastes, and other soil organisms. Organic matter is constantly being broken down by cultivation, soil organisms, and climatic factors. When it is almost completely decomposed it is referred to as humus. The proportion that is lost must be replaced each year to ensure a healthy soil.

Organic matter plays a very important part in the quality of your soil. It provides nutrients for the plants as well as the organisms that reside in the soil. The soil is able to hold a greater quantity of nutrients when organic matter is present. It improves the structure of the soil by acting as a glue creating differing sizes of soil particles which is necessary for good soil aeration and proper drainage of excess water. It reduces erosion and compaction of the soil. It improves the water holding capacity of the soil. The colour of the soil becomes darker as the content of organic matter increases which helps the soil warm earlier and retain more heat in the fall reducing the risk of frost damage.

In natural areas, organic matter is added to the soil annually by leaves and needles from the trees, dying grasses, droppings from animals and dead animals. To create a healthy soil, we must copy nature. Unless crop residues are diseased, we should till it in or compost it so we may add it later. If possible, we should rotate crops so that we may plant material that will be tilled in to improve the soil (green manure). Peat moss, farm manures, or compost should be a regular addition to your garden.

With all the types of composters available today, composting can be carried on even in the city. Many areas are promoting composting to reduce the amount of material going to landfills. Peat moss can be bought by the bag at any garden supply centre or by the truckload if you live in an area where it is readily available. Manures can be obtained from local farmers especially dairy operations, feedlots, and pig farms. Manure should be aged before adding to the garden or it will burn your plants and have an odour which will offend your neighbours. An excellent source of manure in some areas is from mushroom growers. You can also create your own manure by treating straw with ammonium sulphate, lime, and superphosphate.

The nutrients in organic material cannot be used by the plants until it is broken down into its basic components. Insects play their part by chewing up plant material into smaller pieces that will take less time to break down. Fishworms also play a major part in making the nutrients in organic matter available to plants. The worms eat the plant material and excrete a form of manure that has a high nutrient value. They also help aerate the soil. In areas where the soil is not tilled regularly, the earthworms play an important role in mixing the organic matter that was deposited on the surface of the soil down into the top layer of the soil where it is needed. Many people consider worms a nuisance but their benefits outweigh any problems except where plants are grown in containers. That is the one place where they do more harm than good because of the small area of soil involved. Some golf courses have taken advantage of the fact that earthworms thrive under the conditions that exist there i.e. well fertilized, irrigated turf. They collect and sell the worms giving them several thousand dollars income.

COMPOSTING

Most plant material can be composted. Even weeds can be composted unless they have gone to flower or seed. Avoid diseased plant material and material that has been treated with herbicide. This should go in the garbage. Wood products do not compost well and if used, only small amounts should be added to the pile. When adding material such as wood chips, it will be necessary to add ammonium sulphate to ensure that sufficient nitrogen is available to the micro-organisms that aid decomposition. Do not put meat and similar products in the compost pile. It will attract flies and animals. The plant material should be chopped up to speed up decomposition. This can be done with a spade. For a large amount you might consider a chipper/shredder. If the material is too tough to chop with the spade, it is too tough to compost.

Today everyone has the capability to compost their plant waste. There are many types of composters available besides the good old compost pile. Some cities even sell composters at a reduced price to encourage their use.

A compost pile is the most economical method to use if you have the space. A well constructed compost pile that is working well will not give off any unpleasant odours. The moisture level of the pile should be about 50% to allow it to work efficiently. Dry compost will not decompose and soggy material will be undergoing anaerobic decomposition which produces a foul smell. The speed of decomposition also depends upon temperature so in the north it takes longer for compost to be ready to use than it would in the south. As the compost works, the temperature of the pile increases destroying most weed seeds etc. The pile should be turned to move the outer material into the centre. The number of times a pile should be turned varies greatly depending upon the book you read. Some say only once, some say every week. I usually only turn my pile once and I find that is satisfactory for our short summers.

The compost pile should be built 6 feet wide X 4 feet high X any length. The top of the pile should be concave to collect rainwater. It there is excessive rainfall the pile should be covered to prevent excess moisture levels. There are varying methods to building the pile. One method is to layer the organic material alternately with a thin layer of soil. Another method uses alternate layer of organic material and grass clippings. A light sprinkling of nitrogen is added to alternate layers. Layering organic material with old sod is another method.

You can also use bins made from lathing or chicken wire to hold your compost. Two bins allows you to fork the material from one bin to the other. Having more than one compost pile/bin allows you to have compost at varying levels of decomposition. When your pile has a sweet smell, it is ready for use.

soil.html
This page by Pat
updated August 18, 2000

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