Articles

PURPOSE

The purpose of this report is to give a description of the materials that Texas Crushed Stone Company produces for use as agricultural limestone. We are proud of the quality of our product and the contribution that it has made to the farmers in lime deficient areas. This report is designed to show how our products rate against the two most common and widely accepted measures of agricultural limestone quality; Chemical Analysis and Fineness of Grind.

CHEMICAL ANALYSIS

Primarily two things are accomplished with the use of agricultural limestone. First, the minor elements of calcium and magnesium are provided for plant growth. It is important to note that in almost every case where the soil is acid, the element calcium is needed. It is only in some cases that magnesium is needed. Where magnesium is needed, it is rare that it is needed in the quantities that the calcium is needed. Usually, it is in a ratio of nine parts calcium to one part magnesium.

The second, and probably most important thing that is accomplished with agricultural limestone, is the neutralization of the acid in the soil. This is very important because it determines the availability of all plant foods to the plant.

The amount of acid that agricultural limestone can neutralize is determined by the chemical analysis of the Aglime. In the agricultural limestone business, pure calcium carbonate (CaCO3) has been chosen as the standard. Thus, calcium carbonate is said to have a calcium carbonate equivalent of 100%. All other chemical compounds found in agricultural limestone are rated against calcium carbonate to determine the amount of acid they will neutralize.

CHEMICAL ANALYSIS AND CALCIUM CARBONATE EQUIVALENT OF THE AGRICULTURAL LIMESTONE PRODUCED BY TEXAS CRUSHED STONE COMPANY

Agricultural limestone sold by Texas Crushed Stone Company is produced at the Georgetown quarry. A typical analysis of the stone is as follows:

• 87-92% Calcium Carbonate
• 9-12% Magnesium Carbonate
• .5-1% Other Elements

Magnesium carbonate (MgCO3) has the ability to neutralize more acid per pound than calcium carbonate. Therefore, it has a calcium carbonate equivalent of more than 100%. It can be seen that our agricultural limestone has a calcium carbonate equivalent of around 98%.

The speed that the agricultural limestone reacts with the acid in the soil is influenced by the chemical analysis of the material. The more magnesium carbonates in the limestone, the harder the stone. The stones that contain a very high percentage of magnesium are usually very hard and granular and tend to resist a chemical reaction with acid. The stone with a high percentage of calcium carbonate tends to be

soft and chalky and react rapidly with acid. The amount of magnesium carbonate in our agricultural limestone products, approximately 10%, does not seem to slow its reaction with acid noticeably. However, the most important factor in determining the speed of reaction with acid is not the chemical content of the stone, but rather how finely the stone is ground.

THE FINER THE FASTER

The finer the liming material is ground the faster it will neutralize the acid in the soil. All agricultural limestones are made up of particles of various sizes. In an effort to assign value to the various particle sizes found in agricultural limestone, Ohio State University has developed the following efficiency rating system.

Particle Size	Efficiency Rating
Material passing a 60 mesh sieve	100%
Material passing a 20, but not a 60 mesh sieve	60%
Material passing an 8, but not a 20 mesh sieve	20%

From this it can be seen that material larger than a 20 mesh is of limited value as agricultural limestone.

Grinding stone into very small particles is a slow, costly process. In addition to cost, the finer the limestone, the more difficult it is to handle, transport and spread. Because of this, we have developed two different grades of limestone to meet the needs of the individual customer.

TCS #462 PREMIUM MAGLIME

Premium Maglime is our “standard” agricultural limestone, and meets the specifications for ASCS support in both Louisiana and Texas. Although it is the coarsest of our limestone materials, it is an excellent product which has proven itself over the years as a low cost, easy to spread Aglime. Approximately 57 to 68% of this material has a “neutralizing” value to the farmer.

TCS #465 SUPER FINE AGLIME

Super Fine Aglime is an extremely fine ground agricultural limestone. Approximately 97 to 99% of this material has a “neutralizing” value to the farmer. Due to the extreme fineness of this material, it is more costly to make and more difficult to handle and transport. However, by using this super-active material, the farmer will get a very fast reaction in the soil.

SUMMARY

• The quality of agricultural limestone is primarily based on two factors; chemical analysis and fineness of ground.
• The chemical content of the agricultural limestone produced by Texas Crushed Stone Company is better than most of the material on the market. We produce high calcium limestone with
• approximately 10% magnesium carbonate. The calcium carbonate equivalent will usually run around 98%. Texas Crushed Stone will guarantee that it will always exceed 95%.
• Texas Crushed Stone Company has been selling agricultural limestone for over 60 years with excellent results.