Ag-Lime compared to Pulverized/Pelletized Lime
First to understand the pelletized lime and what it can do. This is AgLime which is pulverized to a very fine powder and then made into pellets so that it can be distributed through a fertilizer spreader. It breaks down very quickly (minutes) as compared to AgLime which may take 3 years.
Understanding How to relate AgLime recommendations to Pelletized Lime.
Most soil labs give recommendations on how much AgLime is needed to bring the soil PH back to 6.5.
1. These recommendations are based on (A the Buffer PH figures which are based on the active and inactive calcium in the soil and (B the AgLime to be used.
2. The lbs of AgLime needed gives consideration to the results of multiplying the purity (also known as CCE) of the material and the fineness (how much goes through different sized screens) and this figure gives the ECCE (Effective Calcium Carbonate Equivalent) figure which is between 75-80% in the states of Oklahoma, Kansas and Colorado (each state has figures depending upon the quarry being used).
3. So, if the purity (info from University of Nebraska) is 80% and the fineness is 75% then the ECCE is 60%.
4. Now, to figure it further with the 60% ECCE, for every .1 below the buffer PH of 7.0 it will take 1000 to 1200 lbs per acre to take the base PH up to 6.5. If it was a buffer PH of 6.5 that would be .5 or 5 tenths below 7.0 and that would call for 5000 to 6000 lbs per acre of AgLime based on the ECCE of 60%.
Now to figure the same problem using the pulverized/pelletized materials.
1. The fineness and the purity must be refigured and the ECCE number will be higher because this material is pulverized to a greater extent (prior to pelletizing).
2. If the fineness figure is changed to reflect that 98% of the material goes through the 60 mesh screen and the purity is changed to 90% (U of N chart) then the ECCE figure changes to 88.6 or let’s just say 90% to round it off.
3. That change is 50% from the 60% ECCE normally used (actually the University figure given is .60 so we’ll go with that) which means that the recommendations will be cut to 600 to 720 lbs per acre per .1 of the Buffer PH needed because of the greater effectiveness of the material because of more smaller particles which breakdown more quickly and easily as they become a part of the soil solution.
4. NOW, the interesting thing is that the above figures are correct for the 98% example given except that the actual figure for this pelletized lime is 75% through a 200 (yes, two zero zero) mesh screen !!
5. Now we’re working with numbers the University doesn’t have, but the scale has to keep sliding as this will be another big drop in the amount of lime needed per .1 of Buffer PH to raise the PH to 6.5. We don’t know exactly because the University bases their figures on the 60 mesh screen instead of offering any working finer screen numbers.
6. However, if we can postulate it would seem that the material going through a 200 mesh screen would be at least twice as effective as the 60 mesh screen materials and therefore the amount of materials needed per .1 of Buffer PH under 7.0 should be around 200-400 lbs per acre or less.
It should be noted that the C.E.C. (Cation Exchange Capacity) of each soil is automatically taken into the formula in order to figure the Buffer PH. The CEC is a measure of the soil type whether it is sand, loam, clay, silt or a combination.
It also should be noted (if not already understood) that the finer the grind of limestone, the more quickly it breaks down and gets into the soil solution for transportation up into the plant by the microbial activity.
Most of the pulverized material will be used up as plant food (working in conjunction with other soil minerals). Thus it’s feasible that Nitrogen rates could be cut while still seeing good growth rates. Generally, the pulverized material is considered a “food” and not a soil builder. You can use the AgLime to build your soils.




Comments