2 Apr 2004 by Hipper
Soil Tests
How accurate are soil tests
Soil tests are carried out on my cricket square around October each year and have been done by reputable companies and yet in these four years the results vary wildly.
Looking at pH, in autumn 2001 the pH was 5.0, and I've been attempting to raise it by adding Rigby-Taylor's microcal at slightly below the recommended dose. in 2002 the pH was 6.0; I was surprised how high it was but pleased too. Then in autumn 2003 it was down to 5.1. The base saturation levels have also changed by large amounts.
I appreciate that climate, irrigation and perhaps other factors can intervene, but with a broadly similar programme of work on the square each year, and the samples taken in the correct way (a W formation of cores) why should there be such a variation?
How much reliance can we put on these analyses to govern future work programmes?
2 Apr 2004 by mackay
ph
I too have experienced this problem with regards to ph levels. Ph levels do seem to fluctuate alot depending on the soil tests done and who does them.
Home testing kits are not all that reliable either.
Since the ph scale is logrithmic, if ph7 is neutral, ph6 is ten times more acidic than neutral, and ph5 is 100 times more acidic etc etc. Therefore, although ph does change slightly depending on conditions, there is no way that it can change so much without some sort of drastic interaction!
I reackon the best way is to build up an idea of ph levels from various tests: both professional and ones you can do yourself - discarding any which seem as if they may be false (based on the majority).
Don't get too bothered about ph though - especially on a cricket square! I'm not saying that it is unimportant (it is) but there is not that much you can do to make a quick difference (as you will be aware). keep applying the product you are using. Always take professional advice before liming because apart from other problems (like take all patch disease), liming a clay based soil will destroy its structure (floculation) and that is the last thing we want on a square!
To grow ryegrass ideally you should have a ph of between ph6 and ph7 (roughly) so if you think your soil is acidic - even is one reading is at ph6.0 - then you can afford to keep raising it. keep testing each year though.
Something which I am trying to find out about is fertilisers which contain calcium nitrate rather than amonium nitrate. Amonium nitrate fertilisers acidify the soil alarmingly if not amended with an alkaline agent. By using calcium nitrate fertiliser i hope to gently raise the ph without doing anything out of the ordinary.
3 Apr 2004 by anon
soil tests
small ph test kits are available and reliable you can keep your own records and compare them against the pro? results i often use this method
test kits
I bought a (ten quid) soil tester which has a couple of probles to check moistur at various levels. It also came with a ph indicator as part of the (instrument?)
Can anyone give an opinion as to the likely accuracy?
from Land of Paspalum & Bermuda
3 Apr 2004 by mackay
test kits
ph maters are notoriously inaccurate.
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