Soil pH

In rotations involving legumes such as alfalfa and clover, in order to take enough time to react with soil, it is necessary to use lime before planting the beans. Ideally, you should apply lime three to six months before the target crop is planted. Application before planting is still beneficial in strongly acidic soil with good soil contamination. After the application of typical agricultural limestone for about 1 year, the maximum pH rise is usually not achieved, but some decline in soil acidity still occurs.

Placement is as important as lime quality. Maximum exposure to soil is important to neutralize soil acidity. The most common lime treatment material is only slightly soluble in water. For example, ammonium nitrate is about 84,000 times more soluble than pure calcium carbonate. Even if lime is adequately mixed in the plow layer, it will hardly react if the soil is dry. There must be moisture to react with limestone. The best way to combine lime or any other material with a plow layer may be to use two vertical channels of a combined disc followed by a chisel plower. Even if you plow the lime deeply, you will not get the desired mixing at the top 6-8 inches of the soil. However, the lime is reversed by a plow or heavy shredder, which helps to distribute the lime to the upper part of the lower soil. The choice of agricultural equipment will depend on the depth that is most needed for the neutralization of soil acidity. Good mixing of lime horizontally and vertically gives the best results. In some planting systems, such as established perennial lawn or established no-tillage crop production, it is impossible to mix lime with plow layers. Before establishing these planting systems, lime should be added to adjust the pH of the plow layer. Once the desired pH is reached, it can be maintained by surface application in these non-tilling systems. The lime-coated surface reacts more slowly than lime is mixed with soil, usually affecting only the top 2-3 inches of soil pH. According to a study at Penn State University, when lime is sprayed approximately every 3 years, surface spraying of limestone in the non-tillage crop production may begin to affect soil pH after 4 years. Surface treatment with 6,000 pounds of lime / A every 3 years is as useful as applying an annual lime of 3,000 lbs / A.

The more crops produced, the more nitrogen and fertilizer are used, the more crop yield (and nutrient removal) is increased, the more lime needs to be used, the more frequently it is used. Soil sampling is the best way to assess soil pH and lime demand

Soil pH or soil reaction is an indicator of soil acidity or alkalinity as measured in pH units. Soil pH is defined as the negative logarithm of hydrogen ion concentration. The pH is 0 to 14, pH 7 is the neutral point. As the amount of hydrogen ions in the soil increases, the pH of the soil decreases and becomes more acidic. When pH goes from 0 to 0, the soil becomes increasingly acidic, and when pH goes from 7 to 14 the soil becomes more alkaline or alkaline. Many dyes discolor as pH increases or decreases, making it possible to estimate soil pH. As soil pH was measured, the sample was saturated with dye for several minutes and color was observed. This method is sufficiently accurate for most purposes. The Garden Store offers a kit (pH) that contains the necessary chemicals and color charts.

Soil acidity is measured in units of pH. Soil pH is a measure of hydrogen ion concentration in soil solution. The lower the pH of the soil, the higher the acidity. The pH is measured on a logarithmic scale of 1 to 14 and 7 is neutral. Soil acidity at pH 4 is 5 times soil pH, soil pH is 6 times, soil pH is lower than soil pH 6. Low pH values ​​in soil may affect microbial activity, the most obvious is It is a decrease in legumes. The nitrogen deficiency resulting from plant root nodulation may be manifested by the redness of the stems and petioles of herbaceous leguminous plants, or by yellowing and death of the oldest leaves of cereal beans. Rhizobium is drastically reduced in acidic soils. Some grass legume plants may not survive because the root nodule population can not normally root nodulate roots and form functional symbioses

Soil pH can be measured with a simple device called an ion electrode which puts a part of soil moisture in a mixture of 5 parts of water. Scientists dealing with acidic soils with an acidity of less than 5 prefer to measure soil pH using soil in calcium chloride solution. It has a pH greater than 5, as some ions (mainly bicarbonate and carbonate) in these soils are bound to calcium and removed from the solution, which leads to incorrect pH reading It does not apply to soil. Soils with a pH above 5 need to be measured in water