Whatever you prefer to call it, many IAAP member companies supply this vital agricultural amenity to farmers in Illinois and neighboring states.
The Illinois Association of Aggregate Producers has learned that the Illinois Department of Agriculture (IDOA) will not be able to test aglime samples this year. The IDOA lab was shut down to protect employees from the spread of COVID-19 and remains closed. The lab’s director does not anticipate it will reopen in time to test aglime before producers begin selling it. IDOA has decided to repost the 2019 results along with a statement that the IDOA lab was unable to test 2020 samples due to circumstances beyond its control.
There are four major factors that affect the successful neutralization of soil acidity by agricultural limestone. They are: 1) lime rate: 2) lime purity…compared to pure calcium carbonate …expressed as calcium carbonate equivalent (CCE); 3) lime particle size distribution or fineness of grind; and 4) degree of incorporation or mixing with the soil.
Soil test laboratories make lime recommendations based on a measurement of soil pH (active acidity) and some indication of soil texture or buffer capacity, which is the resistance to change in soil pH. Most soil testing laboratories usually assume the aglime has a CCE of at least 80 to 90 percent and an excellent fineness of grind (i.e. large majority of particles passing a 50 to 60-mesh sieve).
Different states have different regulations governing lime quality, and many land grant universities offer guidance in selecting good quality aglime. Often, lime quality is expressed as “effective calcium carbonate equivalent”, “relative neutralizing value”, or “effective neutralizing material.” These expressions involve some consideration and factoring of both lime purity and fineness of grind.
The rate of reaction or the dissolution of lime particles increases as their size decreases. For example, after 3 to 4 years, aglime particles larger than 10 to 15-mesh (about 1 to 1.7 millimeters in diameter) will have dissolved little, while the majority of aglime particles in the 50 to 60-mesh size range will have dissolved. Particles larger than 10 to 15-mesh have little effect on soil acidity, while the smaller, finer-grind particles react rapidly to neutralize soil acidity. It may take twice as long (or longer) for particles between 15 to 30-mesh to react, compared to particles smaller than 50 to 60-mesh (about 250 to 300 micrometers), assuming their purity or CCE is the same.
With the expansion of conservation tillage and no-till systems, there are fewer opportunities to incorporate aglime via plowing or discing. So, lime quality may be even more important in these reduced-tillage systems than in older, traditional tilled systems.
High crop yields are essential to economic success in farming. Most farmers and crop advisers recognize the importance of managing soil pH at optimum levels in the crop root zone to achieve high yields. When acidity increases to the point that root growth slows, nutrient and moisture uptake are impaired, the function of certain herbicides becomes limited, and yields decline…can one afford to purchase and apply poor to mediocre-quality aglime?
Because of the recent changes in production costs associated with higher energy costs, farmers and their crop advisers are seeking greater confidence that each input will result in economic benefits. When purchasing and applying aglime to acid soils, it pays to know both the aglime purity and fineness of grind.
From Fall 2006, No. 5, Agri-Briefs, Potash and Phosphate Institute (Download)
Members of the IAAP's Aglime committee are committed to a partnership with the Illinois Department of Transportation (IDOT) and Illinois Department of Agriculture (IDOA) to ensure the products produced and supplied by our members for agricultural use are the best quality available.
The Illinois Department of Transportation (IDOT) will begin the sampling window on April 1st and continue until May 31st and has committed to have all samples delivered to Illinois Department of Agriculture (IDOA) by June 15th.
Aglime producers must contact their local IDOT district office to make a request that samples be taken of your aglime stockpiles. IDOT inspectors will use an aglime submittal form gathering information from producers that will be used to ensure test results are conveyed to the appropriate person at the producer company and enhance the information contained in the Illinois Voluntary Limestone Producer Information booklet. IDOA will not accept aglime for testing directly from a producer; aglime samples must remain in IDOT possession until arriving at the IDOA lab. IDOT inspectors will not offer aglime producers the option of a split sample. You may take your own sample for independent testing; however, limited retesting is still available as outlined below.
IDOA expects to begin testing samples in mid-June. Testing will be done on ICP equipment using an approved ASTM method and anticipates completing testing by July 31st.
Data entry will be done into an Access database that can produce batches of results in spreadsheet form. These batches will be passed along to IAAP who will send results to individual producers via email.
Producers may request limited retesting of aglime samples if they believe the testing results are inaccurate. A retest request must be made to the IAAP and done so during the time the IDOA lab is conducting aglime testing. Retests will be done using the original sample. An aglime producer may also ask for return of some sampled material for testing by an independent lab. Prior to publication of the Illinois Voluntary Limestone Producer Information booklet, a producer may ask the IAAP to omit one or more of their aglime results. Test results from independent laboratories will not be published in this booklet.
IDOA will use email to send Limestone Analysis Reports to producers when all laboratory analysis are completed.
IAAP will compile the Illinois Voluntary Limestone Producer Information booklet for publication by early August.
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