If your soil is not, then you will need to make a choice. Either choose plants adapted to your soil's pH or alter your soil's pH to fit the plants. But before attempting to raise or lower your soil's pH, you should first conduct a soil test to determine your current soil pH. Contact your local county Extension office for advice on collecting and sending a soil sample to a laboratory for analysis.
Some soils in Iowa especially those in western Iowa are slightly alkaline to very alkaline, with pH's that range from 7. This is due mainly to the limestone parent material from which the soils were formed. In addition, home builders may remove topsoil during construction and replace it with more alkaline subsoil. Alkaline building materials, such as limestone gravel and concrete, and high pH irrigation water may also contribute to a soil's alkalinity. If your soil is alkaline, you can lower your soil's pH or make it more acidic by using several products.
These include sphagnum peat, elemental sulfur, aluminum sulfate, iron sulfate, acidifying nitrogen, and organic mulches. An excellent way to lower the pH of small beds or garden areas is the addition of sphagnum peat. The pH of Canadian sphagnum peat generally ranges from 3. Sphagnum peat is also a good source of organic matter. On small garden plots, add a one to two inch layer of sphagnum peat and work it into the top 8 to 12 inches of soil before planting.
The addition of sphagnum peat to large areas would be cost prohibitive. Granular sulfur is the safest, least expensive but slowest acting product to use when attempting to lower your soil's pH. It is calculated by multiplying the CCE expressed as a decimal by the relative reactivity based on fineness.
Size standards and other criteria have been established by the state of North Carolina for the sale of agricultural liming materials to ensure a quality product. They are:. The most commonly used liming material in North Carolina is finely ground dolomitic rock, but calcitic lime is also widely used.
Additional liming materials include burnt lime or hydrated lime, pelleted lime, liquid lime, wood ash, and industrial slags. North Carolina has few good natural lime sources. Calcitic marl liming materials soft marine shell deposits are available in the coastal plain, but there are no dolomitic lime deposits in the east.
Dolomitic lime is commonly obtained from the mountains of Virginia or Tennessee. Most agricultural lime is sold in bulk as a damp powder because dry lime is very dusty and difficult to handle and spread. However, lime is occasionally excessively wet. Because lime is sold by the ton, you should be aware you may be purchasing a substantial amount of water.
You should adjust lime rates accordingly. Lime pellets are not large grains of solid limestone; they are formed from lime that has been finely ground. Pellets are less dusty and easier to spread, but they are more expensive than powdered lime.
Pelleted lime comes into contact with fewer soil particles than finely ground lime. As a result, soil pH changes are slower with the pellets. Soil reaction will be enhanced if the soil can be tilled several days after the pellets have been mixed into the soil and become soft. Pelleted lime is convenient for landscape use, but is not an economical source for most field crops. All the lime particles must be mesh or finer.
Up to 1, pounds of lime can be suspended in a ton of liquid product. The main advantages are ease of handling and precise application. Although it is a fluid, this material does not react any faster than dry lime of the same particle size.
All of the lime in a suspension is fast acting, and a ton of product 1, pounds of fine lime particles plus clay and water will raise the pH as fast as a ton of dry lime. However, due to particle size and enhanced initial reactivity, the effectiveness is short lived, compared to regular agricultural limestone, and liming will probably have to be repeated every year.
Suspensions may also raise soil pH slightly above the target pH, and they are a considerably more expensive way to correct soil acidity. Occasionally, industrial byproduct liming materials become available. If the neutralizing value is known and the material is ground finely enough to react in the soil, these can be economical substitutes. Often such materials contain other plant nutrients.
Wood ash and steel mill slag are two examples of such products. These products must meet the legal standards above to be sold as liming materials in North Carolina. Even if they do not meet all of the standards, they can be sold as fertilizer and may still be capable of reducing soil acidity and supplying a variety of nutrients. If a product does not meet all the specifications of the lime law, the supplier is barred from making claims about liming effectiveness, and the purchaser must have the material tested.
Each lot of such materials should be analyzed, as considerable variation in CCE and fineness may occur. As with conventional lime, the ENV needs to be known in order to determine the appropriate application rate.
The actual materials available for application vary widely. VanCleave, Janice Pratt. Thompson, Ralph J. A neutral solution with equivalent amounts of hydrogen and hydroxyl ions has a pH of 7. Acidic solutions have a pH of less than 7. Titrations are used for chemical analyses. Books Kostiner, Edward. Study Keys to Chemistry. Barron's Educational Series, Inc. Acid —A chemical substance that donates a hydrogen proton when it reacts with a base.
In time, reserve elements are depleted enough to cause acidity. When you apply lime, consider the size of the reservoir or buffering capacity. Typically, clay soils have a larger reservoir than sandy ones, which means that they require more lime to achieve a favorable pH.
Pay attention to the buffer index or pH on the soil test because it is an indirect estimate of the soil reservoir's size. Because the lab test involves adding basic material to soils with a pH less than 6.
If the buffer pH is 6. The correct pH depends on the crop being produced. Grasses tend to tolerate acidic soils better than legumes, so liming to pH 5. Legumes, however, need more calcium and perform best between pH 6.
Table 2 indicates the pHs preferred by common field crops. If you produce wheat continually with no legume component , the minimum amount of lime to apply is 0. Lime requirements are expressed in terms of ECCE , which is established on the basis of two components: the purity of the lime, determined chemically by the calcium carbonate content in the lime material, and the fineness of the lime material, determined by how much it is ground.
The more calcium carbonate and the finer the material size, the higher the ECCE. Because the ECCE of lime is not always percent, the amount of material required to provide that percentage must be calculated:.
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