I'll give you my perspective. At home I have 35 acres. A mix of poor upland and dry drained bogland. Land is too wet to spread lime in spring and I'd lose too much ground to spread 20 ton in autumn. Also, I wouldn't put on any more than 1/2 ton per acre any year because too much lime will make my ground very soft - and no contractor will do that for me.
So last year I bought 3 ton of gromax
http://www.irishlime.ie/our-products/quicklime/growmax
€180 per ton if I remember correct.
It was spread at about 100kg to the acre at the same time as I was spreading the fertilizer. (unlike ground lime, you can there is no waiting period between it and fert or slurry).
I know that last year was a good year so results are a bit tipped but:
1. I have a paddock system and noticed that grass growth was about 25% faster than any other comparable year.
2. Buttercups are dead, so is a lot of the crowfoot and other weeds that was making up the swart.
3. Meadows were 25% heavier and regrew a lot faster in comparison to other years.
4. Rushes were significantly reduced on the farm.
5. I have had a lot of grass grow over the winter in comparison to other years.
The growmax was spread in early april and I noticed that by autumn, if you got down on your knees and went searching through the grass roots, you could still find some of the pellets - they were slowly breaking down, but did not wash into the ground in the first shower.
The proof of the pudding is in the eating - my most recent soil tests show a ph of 5.8 on my boggy land and 6.5 on my upland. However, in comparison to this time last year, when my bogland was 5.0 and upland 5.9, I am at a good starting base and I plan just to spread 50kg of growmax per acre in order to maintain ph levels and to monitor ph levels.
Everyone talks about the cost of granlime. Here's the way that I looked at it. In our Suckler Discussion group, our advisor challenged us to spread at least 80kg of growmax per acre and reduce our spend on fertilizer by the amount that we spent on the growmax. He even advised that if we spread growmax (or any granlime) without spreading fertilizer at all, then we would see an increase in grass growth due to the lime helping the grass to make better use of the nitrogen already in the ground.
I reduced my fertilizer spend for this particular farm by approximately €520, but I don't think that I'm exaggerating when I say that I saw far more than €520 (worth of fertilizer spread) improved grass growth, improved grass quality, decrease of weeds, etc. etc.
So what did the granlime cost me?