Basic slag has been around Alabama since it was first ground and bagged at the Ensley plant of US Steel Corporation in 1951. Because of its availability and low cost, this was probably one of the very first soil amendments used on some Alabama cropland.

How is it made

In the process of making steel from iron in the open hearth, iron ore, coke, limestone, and a flux are used. The limestone removes unwanted elements from the steel such as phosphorus and some metals. Some of these elements are essential plants nutrients. The slag is drawn off, cooled, stockpiled, and crushed into what farmers call basic slag.

Plant Nutrients

When fertilizers were low analysis and difficult to transport great distances, basic slag soon became a major fertilizer and soil liming material in Alabama and the Southeast. By the time World War II began, basic slag ranked second only to super phosphate in the worldwide use of phosphorus fertilizers. Most of today’s basic slag contains less then 1 percent P2O5. It still contains many of plant’s secondary and micronutrients needs, notably magnesium (6.5% Mg), calcium (24% Ca), iron (26% Fe), manganese (1.2% Mn), and zinc (0.1% Zn). The actual amount of secondary and micronutrients can vary from one batch to another.

Neutralizing Value

The nutrients that Basic Slag contains are not the only value. Basic Slag is a good, alternative soil liming material because of its basic properties. Today’s Basic Slag has the neutralizing value of minimum quality ground limestone. The source of lime is the crushed limestone used in the steel-making furnace. The intense heat converts the limestone (calcium and magnesium carbonates) to burned or quick lime (calcium and magnesium oxides) that is highly reactive. During cooling and storage, most of the oxides are probably converted to hydroxides and even back to carbonates as the slag reacts with moisture and carbon dioxide in the air. Due to better processing, Basic Slag is now qualified as a Grade A Agricultural Lime by Alabama and will not turn hard when wet. This change in qualification for the Basic Slag has reduced the price by forty cents ($.40) per ton. 

Ground limestone or 
Basic Slag?

That is the question. Basic slag is going to provide the same neutralizing value as ag lime plus some micronutrients that are valuable to the soil. Therefore, the bottom line is availability because the costs are the same. With today’s high neutralizing Basic Slag, one can apply Basic Slag TON FOR TON with ag lime and feel comfortable that Basic Slag will do an excellent job.

Misunderstandings

Basic Slag has had the reputation of not stockpiling well, turning hard, and being too pricey. Today’s D.O.D. Basic Slag stockpiles better than Ag Lime, will not turn hard – guaranteed – and costs about the same. It is an all around perfect liming product for quick reaction, increase in yields of most any crop, especially soybeans, and pastures.

To get D.O.D. Basic Slag in bulk and bag, call your local Quality Co-op store. If you have any questions, please call Agricultural Products, LLC at 1+800-226-9595 between 8 a.m. – 5 p.m., Monday – Friday.