Some companies make things that produce hazardous by products. They usually have to pay a huge fee to properly dispose of it. This could mean dumping in a land fill or processing it to reduce the heavy metals, salts, or other toxicities.
By applying it for "free" on your field, it saves them thousands of dollars per ton, and gets rid of the hazardous material. Be suspicious of free product, have your own complete analysis run on the product by a reputable lab. Avoid anything with heavy metals or aluminum in it, as this will cause nutrient tie-ups and imbalances.
In addition to receiving "free" product you also get too much of it and spread poorly.
For maximum yield you want a proper spread pattern. It does you no good to have a large amount of product right behind the spreader.
In our experience "free" products can show advantages the first year, then as nutrient imbalances develop, yields can crash. This leads to a more expensive treatment of the soil to correct the imbalances caused by over applying free/waste products.
The Blogronomist is maintained by Craig Dick, head blogronomist and VP of Sales and Marketing. Here you will find a wide array of blog articles from Craig and expert guests on topics related to soil and crop health, farming, and so much more. If it’s not here, ask us!