1. Missed the live Ask the Expert event?
    Catch up on the conversation about fertilization strategies for success with the experts at Koch Turf & Ornamental in the Fertilizer Application forum.

    Dismiss Notice

lebanon parex

Discussion in 'Pesticide & Herbicide Application' started by f350, Jul 1, 2002.

  1. f350

    f350 Banned
    from mi
    Messages: 424

    who has the goods on this stuff?? kirby, steve???
  2. MOW ED

    MOW ED LawnSite Fanatic
    Messages: 5,028

  3. KirbysLawn

    KirbysLawn Millenium Member
    Messages: 3,485

    Sorry, I'll be no help here, never used it. :(
  4. mlr164

    mlr164 LawnSite Member
    Messages: 5


    ParEx is isobutylidene diurea (IBDU). It is simply two urea molecules being hels together by a butylene functional group. IBDU nitrogen is released by hydrolysis. Microbial activity doesn't play a role in its release, just moisture.

    If you don't have an opportunity to keep water on it, it probably won't serve your purposes. The thickness of the thatch is also a big influence on its release. The thicker the thatch, the drier the soil, the slower the release. Golf courses usually have fairly good control over thatch and watering, so it might be a better product for them.

    Lastly, particle size matters quite a bit in the rate of its release. There are two different particle sizes (as far as I know), one is .7 to 2.5 mm and the other is .5 to 1 mm. The finer the particle the more surface area comes in contact with water, so you would want the .5 to 1 mm particle size. All I've seen in most landscape settings is the larger particle size, I guess do to cost?
  5. tremor

    tremor LawnSite Bronze Member
    Messages: 1,476

    mlr164 is dead on with the comments.

    I'll apologize right now for what will be one of my longer rants. I like IBDU, but lately have seen it & other strange N sources landing in blends in a way that I feel is a compromise. This is partly due to the SCU shortages & other economic perils faced by the fertilizer blenders.

    The sizing of IBDU blends concerns me with this & all bulk blends. Check this:

    The blend I liked best at that website was the 21-2-20 56% CRN (controlled release N) with a claimed SGN of 230. If the raw IBDU is manufactured at an average SGN of 250, then the Uniformity Index may be fairly wide. A fair amount of very small prills is required to bring the SGN down to the claimed value.

    For those that aren't familiar with SGN- Size Guide Number - Prill size in Millimeters times 100. Usually determined with Tyler Sieves. Mine is a simple device with stainless mesh with holes that are of known size.

    I took a call in my office last week from a guy who was striping all the lawns he did with an ammonium sulphate blend that he applied with his PermaGreen. I suspected the spreader, even though he's used PermaGreens for almost 3 years. He suspected the fertilizer. I asked him why. He had observed that the ammonium sulphate was the biggest sized prill in the blend. He bought it from one of our competitors. A different blend with a much tighter UI (that we did sell him) was used during the same week. Throughout the week, 1 ton of each was applied by him alone. Only the AS lawns were striped. But they striped as consistantly as a greenhorn homeowner with a few too many beers down the hatch & steaks a cookin' on the grill.

    I obtained comparable samples & ran both products through a Sylvite SGN Scale.


    The results spoke for themselves. The 2 products were markedly different in uniformity (hereafter UI). The AS was uniformly the largest sized prill in the blend. I'm not going to say which company produced the suspect blend in a public forum, so please don't ask.

    I'm not bashing IBDU or this blender either. It's a great source of slow release Nitrogen. Kudos to any blender that is willing to pay for, size, screen, blend, and market the material properly. It is unusually expensive for the average LCO. Assuming these blends are made well, then the one I like would be awesome summer material. But I'll bet the cost would also exceed the $20 per bag mark. This would be like me selling my Lawn Care customers our NOVEX golf line. I have a half dozen guys using NOVEX so this isn't out of the qustion. But that doesn't make it a sensible choice for everybody.

    Since much more competively priced blends will do just as good a job for the 8 weeks between service intervals, why would this be a sound recommendation? The burn potential of other summer appropriate blends (from this or any other blender) are negligable & of no realistic concern.

    Good bulk blends are easy to produce when some careful raw ingredient matching is exercised. When raws are carelessly selected (cheaper) and the off-spec materials aren't screened out, then "ballistic particle segregation" (BPS) is known to occur when large scale broadcast spreading equipment is used. Regardless of the source of N, or the SGN, it is the UNIFORMITY OF PRILL SIZE that matters.

    That said, IBDU relies on particle size to establish it's release patern. Big prills are slow with a smaller available surface area. Small prills are quick since the surface area of the same weight is actually greater. No problem at all for a small rotary or drop spreader, but who uses these?

    Let me try to explain.

    Since the bulk density of the raw materials that our industry uses is almost entirely the same, then obviously the largest prills will weigh the most. (Urea is lighter than Muriate of Potash, but for the sake of this post- let's call my claim kosher) When large scale broadcast spreaders are used, the largest particles (heaviest) carry the furthest. That's fine if all the bigger particles are NOT just nitrogen. But look out if ONLY the biggest particles are the IBDU or other source of N. Then the "BPS" will cause striping with some broadcast equipment as the biggest particles land only at the outer edge of the spread patern.

    Meanwhile the smallest particles are falling very close to the spreader. If the soluble N or most of the P & K are sized small, look out.

    So if the blender has chosen to include the entire spectrum of SGN sizes of IBDU in the blend, you should be OK. If the blender chooses to screen out the fines & use them for other blends, then all the rest of the ingredients must be very similar in size or then the problems start.

    Remember that SGN's are an average of all the prills in the bag. UI is the measurement of the variation of prill size after screening & blending.

    A customer & I proved this "BPS" point on Friday last week with a LESCO Truckster & a Permagreen (with the wheels off the ground) in a parking lot. All we did was a quick shot open of the shutoff plates. We observed the paticles' dispersion results on the ground. There was only segregation of the 2 blends that exhibitted a wide SGN. 1 had the ammonium sulpate, the other was a straight urea based blend from an ag-blender. Our own 2 blends (1 lawn care, 1 golf fairway) did not segregate. Even after a good roll on the asphalt. Granted, turf doesnt allow for the type of roll we observed. But what we observed was a little more than just an "asphalt roll". It was BPS. We expected a similar amount of material to throw heavy off the front of the impellers, which may have caused a correction. But for an undetermined reason, that wasn't the case. More large prills still landed at the extreme edges. The next overlapping pass wasn't successful at "fixxing" the now lightly treated area where the wheels were (down the center of the spread patern).

    When things slow down a bit I want to duplicate this test with some strategically placed collection bins & a scale. I would like to also test a stationary Vicon pendulum spreader that spreads 38 feet, which I suspect will be even worse. I doubt that I could post the results since a lawsuit might arise! LOL! But it will satisfy my own curiosity at least. Despite a lot of digging around, I haven't found much in the way of published test results to back my theory. Most of the segrgation results that are published either apply to "Conical Particle Segregation" of loose fertilizer particles in the hoppers & bins that feed the baggers in a plant. Some other data can be obtained from the mining industry.

    The Canadians are leading the way with a slight push to improve, standardize, & label the results of the UI test on the bags you guys are buying. For now though, Americans will either have to perform their own tests (as I do), or put some faith in their own eyes or the word of the blender. I would like to see the UI printed on every bag of fertilizer produced & sold in this country. It is a much more valuble statistic when selecting bulk blends for Commercial Lawn Care than an SGN number ever will be. We spent over $1.3 million on just one plants in & outbound screening equipment after we had "procurred" it. We don't spend that kind of dough just for kicks.

    Sorry again for the lengthy rant, but I'm pretty fed up with some of my colleagues claims that UI doesn't matter when I've seen the results.

    I still like IBDU....When it is sized & blended with the appropriate companion ingredients. To be sure, contact Sylvite, pay the $30. In 2 weeks, you'll have a guage of your own. Then check for yourselves. Don't just take my or anyone elses word for it.

  6. Scraper

    Scraper LawnSite Bronze Member
    Messages: 1,656

    Another great and informative post as usual Steve!
  7. MOW ED

    MOW ED LawnSite Fanatic
    Messages: 5,028

    I agree.
    You cannot find that type of knowlege at the local hardware store or co-op fro that matter.
    Thanks Steve for an excellent and informative post.

    There certainly is more to fertilizing than I ever imagined.

Share This Page