Whether you have sandy, loamy, clay-ish, or some type mix of those- nearly all dirt could use some improvement. What you use & how much of it you need to add will depend on how your soil is now. To figure out what type of dirt you have you'll need to do a soil test
Soil Testing
In agriculture, a soil test is the analysis of a soil sample to determine nutrient content, composition and other characteristics, including contaminants. Tests are usually performed to measure fertility and indicate deficiencies that need to be remedied.
The quality of the original soil sample plays a key role in determining the practical value of test results. Most labs will provide documentation outlining the proper procedures for collecting soil samples.
Soil characteristics can vary significantly from one spot to another, even in a small garden or field. Taking samples everywhere in the field is crucial to get the most accurate measurement of nutrients and other organisms. An example of this is along gravel roads where the soil could have more lime from the dust from the roads settling down in the soil, or an old animal feedlot where phosphorus and nitrogen counts could be higher than the rest of the field.
Sample depth is also an important factor. It is recommended that you take the samples from tillage depth, as this is where the majority of the nutrients and elements are placed mechanically. The presence of various nutrients and other soil components varies during the year, so sample timing may also be important. A good time to take a sample for testing is in the fall after harvesting is finished, but this isn't the only time it should be done.
Sampling and testing in the fall is beneficial because the producer will get the results back in time to formulate the fertilizer plan for the following growing season.
Another time sampling and testing can be done is spring. This is a good way to see what nutrients survive over winter when the soil freezes, as well as if any leaches away from melting of snow and thawing of the soil. This way the producer can know if more or less fertilizer needs to be purchased.
Mixing soil from several locations to create an "average" (or "composite") sample is a common procedure but it must be used judiciously as it can artificially dilute quantities/concentrations of soil components and may not meet government agency requirements for sampling.
Make a reference map for your filing system so you know where you took them, and how many samples you took in the field. All of these considerations affect the interpretation of test results.
You can go (or call) to your Department of Agriculture's County Extension Office & ask for a soil test box. They will provide you one & the instructions will either be on the side of the box or on a separate sheet. Follow the instructions carefully & take your sample back to the Extension Office. For FREE (or a very small fee) they will send your sample off to be tested. Soon you will receive in the mail something that looks much like this:
(click on picture to see larger) This will tell you what your soil is lacking.
Another way to get a soil test is to do it yourself. You can buy a soil test kit in a garden supply shop that looks much like this:
It may not be as precise nor measure as many things, but the major categories will be tested and the results are immediate. Also with a test kit you can retest your soil whenever you want.
To really understand all these measurements you'll need to take a course on soil biology or read a really good book on the subject.
but for the rest of us..............
Simply.... the soil test will give you the pH Level & the amounts of Plant Nutrients in your soil.
The pH condition of soil is one of a number of environmental conditions that affects quality of plant growth. A near neutral or slightly acid soil between 6 and 7 is generally considered ideal for most plants.
To help you better understand pH here is a chart of common substances and their pH:
Example pH Description
Lye(bleach) 13.0 strongly alkaline
household ammonia 12.0
Soap 9.3
Antacid tablet 9.4
Baking soda 8.0
Seawater 7.9
Human blood 7.3 weakly alkaline
pure water 7.0 NEUTRAL
Fresh milk 6.7 weakly acid
Rain 5.6
Sour milk 4.7
Beer 4.4
Coffee 4.2
Orange juice 3.7
Wine 3.5
Vinegar 2.9
Classic Coke 2.5
Lemon juice 2.4
Stomach Acid 2.0
Battery Acid 0.5 strongly acid
Many factors effect pH- what was the parent material, rainfall, leaching, fertilization, amount of decomposing organic matter.
By the application of certain materials to the soil, pH values can be adjusted.
To make a soil LESS ACID ADD LIME.
This is commonly referred to as "sweetening the soil" ground agricultural limestone is most often used. Bear in mind that the finer the grind the more rapidly it becomes effective. Be aware that soils low in organic matter need less lime than soils high in organic matter to effect the same pH change. Generally, for best results, limestone should be applied 2-3 months prior to planting. Even distribution of Lime in the soil is essential, but even when properly mixed in Lime will have little effect on pH if soil is dry. So - Moisture is also essential for Lime/Soil reaction to occur. When applying large amounts to clay soil best mixing comes from a part before tilling or plowing & the rest after. On sandy soil that can easily be tilled 6-8inches one application before tilling is sufficient.
Wood ashes are often used as a substitute for lime.they are a rich source of potash (potassium). Wood ashes can be used to raise soil pH with twice as much ash applied as limestone for the same effect. Ashes should not come in contact with seedlings or plant roots as they may cause root damage. Spread a thin layer during the winter & incorporate into the soil in the spring. Check pH yearly if you use wood ashes. Avoid using large amounts of wood ash (no more than 20lb. per 1,000 sq.ft.) because toxicity problems may occur or the pH may be raised too high. Never use coal ashes which can contain plant toxic (phytotoxic)levels of sulpher and iron.
To make a soil LESS ALKALINE ADD ELEMENTAL SULFUR or ALUMINIUM SULPHATE.
Most horticultural plants require a slightly to strongly acid soil. These species develop iron chlorosis when grown in soils in the alkaline range. Iron chlorosis is often confused with nitrogen deficiency because the symptoms (a definite yellowing of the leaves) are similar. Iron chlorosis can be corrected by reducing the soil pH. Applying chelated iron formulations to the soil or spraying foliage with solutions of iron chelate or iron (ferrous) sulphate is a temporary solution.
Both Aluminium Sulphate and Lime can be purchased at your local garden supply center.
The people there should be able to help you determine how much you should purchase for your garden size.
Plant Nutrients
Scientists have identified 17 nutrient elements that are essential for growth & reproduction of plants.
Plants obtain the three most abundant - Carbon, Hydrogen & Oxygen from the air & water. about 94% of their dry tissue is composed of these three elements. The other 14 combined represent less than 6% of the plant's dry matter. Yet the growth is frequently reduced or limited by a deficiency of one or more of these 14 essential elements, which may be supplied in fertilizer.
These 14 elements are often divided into three groups:
~Primary Group - Nitrogen(N), Phosphorus(P) and Potassium(K)
Nitrogen(N)~
Nitrogen is probably the nutrient whose deficiency most often limits plant growth. This is also the element that gives the visual green-up response most often associated with lawn & landscape fertilization. Plants use large quantities of nitrogen, and most natural soils cannot supply enough to give satisfactory plant performance. Nitrogen is a constituent of all living cells and is a necessary part of all proteins, enzymes and metabolic processes involved in the production and transfer of energy. Nitrogen is a structural part of chlorophyll, the green pigment that is responsible for photosynthesis. Other functions of nitrogen include stimulating rapid, vigorous growth, increasing seed and fruit yeild, and improving the quality of leaf and forage crops.
nitrogen fertilizer sources and their (N) content
source percentage of (N)
Ammonium nitrate 33.5-34.0
Ammonium sulfate 21
Calcium nitrate 15
Sodium nitrate 16
Potassium nitrate 13
Urea 45
Animal tankage 9*
Blood meal 12*
Fish meal 10*
Manure variable
*average value
Phosphorus(P)~
Phosphorus is an essential part of photosynthesis. Plants use the energy of sunlight and phosphorus makes it possible for the energy transfer to be made to the active portions of the plant & photosynthesis to occur. Phosphorus is responsible for utilization of starches and sugars, cell formation & multiplication, cell organization & transfer of heredity.
The availability of phosphorous is related to soil pH. Phosphorous is most readily available at pH 6 to 7 but it is not very mobile in the soil. Due to the importance of phosphorus for root development all of the recommended phosphorous should be applied to gardens and mixed into the soil prior to any planting or transplanting.
phosphorous fertilizer sources and their (P) content
source percentage of phosphorous
ordinary superphosphate 20
concentrated superphosphate 46
animal tankage 10
bonemeal, steamed 22
fishmeal 5
manure variable
Potassium(K)~
Potassium is absorbed by plants in larger amounts than any other mineral element except nitrogen and in some cases calcium. Unlike nitrogen and phosphorus, potassium is not found in organic combination of plant tissues. Potassium plays an essential part in the metabolic process of plants. It is required in adequate amounts in several reactions involving enzymes and is essential to the process by which energy is obtained from sugar- carbohydrate metabolism. evidence shows potassium plays a role in raising the disease resistance and drought tolerance of many plant species.
Potassium is supplied by soil minerals, organic materials and inorganic fertilizer.
In very sandy soils under high rainfall potassium is subject to leaching losses.
potassium fertilizer sources and their (K) content
Source percentage of potassium(K)
Muriate of Potash 60-62
Potassium Nitrate 44
Potassium Sulfate 50-53
Sulfate of Potash Magnesia 22
Manures varies
Organic Fertilizers usually between 1 & 2%
~Secondary Group - Sulfur(S), Calcium(Ca), Magnesium(Mg)
Sulfur(S)~
Sulfur is a constituent of the amino acids cystine, cysteine and methionine and, hence, the proteins that contain these amino acids. It is found in various enzymes and co-enzymes. Sulfur is also present in glycosides which give the characteristic odors and flavours in mustard, onion and garlic plants. It is required for nodulation and nitrogen fixation in legumes. In most soils sulfur is primarily present in the organic matter and becomes readily available upon their decomposition and remains in the soil until taken up by the plant. Sulfur may also be supplied to the soil from the atmosphere in rainwater. Sulfur is used to lower soil pH because it acidifies the soil. Finely ground sulfur should be broadcast and incorporated several weeks before planting because soil microbes are required to convert the sulfur to sulfuric acid.
Calcium(Ca)
An essential part of the wall structure of plant cells, calcium provides for normal trasport and retention of other elements as well as strength in the plant. It is thought to counteract the effects of alkali salts and organic acids within a plant. Calcium is absorbed as the cation Ca2+ and exists in delicate balance with magnesium and potassium in the plant. Too much of any one of these elements may cause deficiencies of the other two. Both calcitic and dolomitic limestone are excellent sources of calcium. when soil pH is adequate and additional calcium is needed, gypsum (CaSO4*2H2O) can be used to supply the needed calcium without changing the soil pH.
Magnesium(M)~
Magnesium makes up a part of the chlorophyll in all green plants and is essential for photosynthesis. It also helps activate many plant enzymes needed for growth. a relatively mobile element, magnesium can be readily translocated from older to younger plant parts. The most common source of magnesium is dolomitic limestone- a material that offers both calcium and magnesium which neutralizes soil acidity.
The Primary & Secondary groups collectively are known as Macronutrients
The third group is
~Micronutrients - Manganese(Mn), Iron(Fe), Copper(Cu), Zinc(Zn), Boron(B), Molybdenum(Mo), Chlorine(Cl) and Nickel(Ni)
These elements are needed in such minute amounts they are labeled micronutrients.
Deficiencies in micronutrients are most likely to limit crop growth in these conditions:
~ highly leached acid sandy soil
~ muck soils
~ soils high in pH or lime content
~ soils that have been intensively cropped and heavily fertilized with macronutrients.
Manganese(Mn)
Manganese is an enzyme-activator involved in the plant growth processes. It's also involved with iron in chlorophyll formation. High manganese concentration may induce iron deficiency in plants.Manganese availability is closely related to the degree of soil acidity. Deficient plants are usually found on slightly acid or alkaline soils.
Iron(Fe)
Iron is a constituent of many organic compounds in plants. It is essential for the synthesis of chlorophyll, which gives plants their green pigment. Iron deficiency can be induced by high levels of manganese. High iron can also cause manganese deficiency.
Copper(Cu)
Copper is essential for growth and activates many enzymes. A deficiency interferes with protein synthesis and causes a buildup of soluble nitrogen compounds. Excess quantities of copper may also induce iron deficiency.
Zinc(Zn)
Zinc is essential for plant growth because it controls the synthesis of indoleactic acid, which dramatically regulates plant growth. Zinc is also active in many enzymatic reactions.
Boron(B)
Boron primarily regulates the metabolism of carbohydrates in plants. The need varies greatly with different plant species. Rates required for responsive crops may seriously damage boron-sensitive crops. Boron deficiency may occur on both acid and alkaline soils but is more prevalent on the calcareous alkaline soils.
Molybdenum(Mo)
Molybdeum functions largely in the enzyme systems of nitrogen fixation and nitrate reduction. Plants that can neither fix nitrogen nor incorporate nitrate into their metabolic systems because of inadequate molybdenum become nitrogen deficient.
Chlorine(Cl)
Chlorine is an enzyme activator for one or more reactions in which water is split for photosynthesis. Chlorine deficiency is not likely to be a problem along coastlines where the air from the ocean provides traces of chlorine in rainwater necessary for plant growth. The general use of muriate of potash in fertilizers is another common source of chlorine.
Nickel(Ni)
Nickel has recently been recognized as an essential plant nutrient, since 1987. Nickel is important in nitrogen metabolism, because it's a component of the enzyme urease, which converts amonium in plant tissues.
This post on soil became more involved & took much longer than I originally intended, so I am doing Soil in at least 2, maybe 3 parts....
Next up will be Composting; Building Better Soil; and Fertilizing.
Be sure to see all the posts in this series for more info! |
