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SOIL-COMPOSITION AND MANAGEMENT
This article is from the Advanced
Grower's Handbook.
Purchase the complete handbook online.
TYPES
The soil functions principally as a container for water and plant nutrients. Here the roots of the plant may obtain each in the quantities required. The efficiency of the soil depends upon its structure, that is, the size and the nature of its particles. Soils are principally of three types--clay, loam, and sand. Pure clay and predominantly sandy soils are difficult to use for growing. The preferred types are sandy loam or clay loam.
Clay particles are very fine; they pack tightly when wet and give up moisture slowly. Rootlets and air penetrate clay soils at a slower rate than they do in sandy soils. Clay soils are much improved by the addition of sand and organic materials. The addition of organic materials in the process of decomposition, such as rich compost, peat moss, and/or rotted manure, cause granulation of the soil. Organic materials improve drainage and will help in the aeration of clay soils. The same materials will also improve the water retention ability of sandy soils.
A grower should know his own soil types which will then determine many of his cultural procedures. Clay and sandy loam soils which drain slowly will demand less fertilizer than sandy soils which leach out and drain rapidly. Surface water is retained longer in clay and clay-loam combinations than in sandy-loam combinations. The latter type soil needs to be fertilized and watered more frequently because its retention is not as great.
ORGANIC MATERIALS
Soil structure deteriorates under continuous cropping and should be rejuvenated by adding some organic matter. To get good soil structure, it takes time as well as effort, but the results are worth it.
Straw is one of the many available organic materials which keeps biological activity in the soil at a high level. This activity, in turn, improves soil aggregation and texture. The results are improved aeration and drainage.
Straw has several advantages over manure as an organic material; it is a uniform product and a grower may expect consistent results. Straw usually costs less than manure and is nearly always available. Straw breaks down easily.
All organic material ultimately breaks down into carbon dioxide, water, and inorganic salts. However, before these products are produced, many intermediate substances useful as nutrients are formed through bacterial action. Each year, an annual incorporation of new organic material is necessary in the planting beds. The use of partially decomposed organic materials reduces the competition between soil bacteria and plants for nitrogen which has been added as fertilizer.
Fresh organic material in the first stages of decomposition will use much of the available nitrogen. This is a temporary situation for, as soon as the primary decomposition is complete, the bacteria die and the nitrogen is released in a form available for plants.
Peat moss is a widely used organic material; it is not broken down rapidly. While peat has practically no nutrient value, it serves a more important function of keeping the soil aggregated or crumbly, thereby increasing the porosity.
SOIL TEST
It is very important for you to obtain a soil test to determine the degree of acidity and the nutrient requirements of the soil in which you intend to grow chrysanthemums. Soil test kits can be obtained through your local County Agricultural Agent. Each kit contains instructions for taking samples from your planting area. Samples should be taken before the addition of any materials, since to do otherwise may result in your providing an excess of some item which might then require special treatment to correct. A soil test each year is recommended.
PH
The degree of acidity of the planting soil is very important. Extremes of acidity or alkalinity can restrict the growth of plants and may even cause death. The measurement of the degree of acidity is expressed on a scale known as pH. The expression pH represents the concentration of hydrogen ions present in the material tested. Natural soils may range from an extremely acid condition with a pH of 4 on the scale to a very alkaline soil with a pH of 9. Neutral soils may be considered as having a pH of 7 on the scale. To grow chrysanthemums successfully you should have a reading near 6.5. To increase the pH of your soil, limestone should be added. To decrease the pH, iron sulphate or aluminum sulphate should be added. The soil test report should give the recommended amount to be added.
PRINCIPAL NUTRIENTS
Upon the receipt of the results of a complete soil analysis, a determination must be made by you as to what treatment your soil should receive. In order to make this determination, there must be an understanding of the optimum requirements of the chrysanthemum. Since chrysanthemums are large leafy plants they are naturally heavy feeders during their growing cycle until maturity is reached.
Plants will make their best response to a balanced feeding program. The following levels of the principal nutrients in the soil will insure a satisfied mum and may be compared to a soil analysis report.
Nutrient Part per Million in Soil
Nitrates 25-60
Phosphate 4-5
Potash 25-50
Calcium 150-250
When one is not certain that his mathematics or computations
are correct in the calculation of materials to be added, the County Agriculture
Agent will be glad to assist.
When plants are young they need quickly available phosphorus to minimize the
shock of transplanting and to give a quick push to extend the root system. It is
again emphasized that the soil mixture into which you place your rooted
cultivars is most important. During the periods of vegetative growth, much
nitrogen is needed, about two or three times more than phosphate and potash
combined. A supplemental feeding with nitrogen compounds may be used, but be
careful to watch for signs of overfeeding.
Begin your year with good healthy disease-free stock and exercise proper soil management. Your advanced growing experience will alert you to unforeseen troubles. We are seldom able to be as precise in our growing operations as the commercial people. It is easier for commercial growers to get the type of crop that they desire, for they are given exact schedules and instructions by wholesale suppliers. Further, commercial mums are generally grown under controlled temperatures and light in glass houses.
CALCIUM
Three forms of calcium are generally available for agricultural use. These are slaked lime, ground limestone, and ground dolomitic limestone. Dolomitic limestone is preferred for the reason that it contains magnesium, a minor nutrient. Slaked lime is not generally recommended for the reason that it is very rapid in its action and over neutralization may result.
Limestone is valuable in reducing excess acidity. If your test reads pH 6.2 or lower and you expect the best results in plant growth, limestone must be used. Ground limestone, slow acting has the following effects:
I . Increases the availability of phosphorus and other elements beneficial to the plant.
2. Improves soil texture.
3. Reduces soil acidity and the solubility of substances such as manganese and aluminum, which may have detrimental effects on plant growth.
4. When dolomitic lime is used, both calcium and magnesium are provided for growth and to promote the acid neutralizing action.
Do not apply too much lime as it may do more harm than good. It is easier to adjust an acid soil condition with lime than it is to correct a soil which is too alkaline. On acid soils or soils which have large quantities of organic material added each year, a normal use would be about five pounds of limestone per 100 square feet per year. Fertilizer companies that process limestone sometimes recommend the use of coarse material rather than the powdered form, as it is easier to handle.
PLANT FOODS
Plant foods are usually divided into two categories, organic and inorganic. Nitrogen is available in organic and inorganic forms.
Organic fertilizers are those derived from something which has lived, either animal or plant, such as bones, hoof and horn, dried blood, manure, leaf mold and other decaying vegetable matter.
Inorganic fertilizers are chemical sails which have no connection with living things. The plant food is much more concentrated in these chemical salts. One precaution with these is to avoid excess quantities which can do very serious damage to the plant.
Many growers consider organic fertilizers to be essential for producing quality blooms. There is no scientific basis for this opinion. For the chrysanthemum plant to take up nutrients the nutrients must be in solution. Inorganic fertilizers are used exclusively by commercial growers and provide a means of providing instant nourishment to the plant.
Chrysanthemums require the essential elements of nitrogen, phosphorus, potassium, sulphur, calcium and magnesium in appreciable quantities if they are to live and grow. They also need small quantities of iron and manganese and minute quantities of the trace elements, boron, copper and zinc.
In addition, the plants need oxygen, hydrogen and carbon. Carbon is obtained from the atmosphere through conversion of carbon dioxide in the air to oxygen through the action with sunlight. The other elements are taken up by the roots from the soil solution.
The three most important of the essential elements are nitrogen (N), phosphorus (P) and potassium (K). If one of these three elements is in short supply, the growth of the chrysanthemum will be adversely affected. Fertilizer mixtures list the quantity of each of these elements, such as 5-10-5. The numbers are the percentage or pounds per hundred weight of the element in the mixture. A 5-10-5 fertilizer would contain 5 percent Nitrogen, 10 percent Phosphoric Acid and 5 percent Potash. The special purposes of each of these essential elements are as follows:
Nitrogen - This element promotes rapid soft growth and makes the leaves a lovely deep green. It is most useful early in the season before the buds are formed on chrysanthemums. If used in excess, particularly with reduced sunlight, the plant will be soft with weak stems. Inorganic forms of nitrogen are potassium nitrate, ammonium nitrate and calcium nitrate.
Phosphorus - This is especially useful for promoting root growth and for 1 ripening the stems of chrysanthemums. Of the several sources of available phosphorus, we find that superphosphates are best known and suited to our use. There are two principle grades of phosphate rock, both supplying readily available phosphorus with a low salinity effect. They are known as Single Superphosphate with an 18 to 20 percent available phosphoric acid and Double Superphosphate with 40 to 50 percent available phosphoric acid. The single superphosphate is preferable. The double superphosphate is a coarse material and is difficult to mix adequately in the soil.
Potassium - or potash promotes sturdy green growth and hard ripe wood. If used in excess, the foliage becomes very brittle during sunny weather and the stems may become so hard that they will not take up water when cut. There are a number of sources of potassium available to the grower. The most common of these are potassium sulphate, potassium chloride and potassium nitrate. Potassium nitrate is most commonly used since it contains both potassium and nitrogen from a single source.
Locate a local chapter and join the National Chrysanthemum Society today.