Dear all,
Following recent advice from this site I applied 2kg of Vitax 50:50 soluble iron in an effort to treat my red thread. The results were impressive, with the red thread disappearing very quickly.
My tennis court has a AMG/Poa problem and a high Ph (7.7) as it sits on top of chalk. Ideally I would like to reduce the Ph to arroun6 to encourage the finer grasses and discourage the AMG/Poa.
Would regular applications of iron reduces the Ph? What else could I do to reduce the Ph?
Is there a maximum amount of iron I could apply over a season?
Would large applications of iron have any other (detrimental) effects on my grass?
What would be the best form of iron to apply chelated, iron sulphate?
Phil
30 Jun 2010 by Anthony Asquith Last edited 30 Jun 2010
Fe will not reduce PH or increase acidity but elemental Sulphur will ie something that will be oxidised to Sulphuric Acid such as Sulphide. Iron does not reduce PH in or of itself but some S forms will.
As far as PH is concerned, do not be too concerned because in practice it is economicaly and practicaly difficult to do such a thing hence why in agriculture they farm chalk downland sites as they are.
AA
There is no real need to reduce pH. Fescues are the indigenous grasses on most chalk downlands. It is not true that you need acidic soil to grow perennial grasses. Fungi that develop in the thatch degrade it to humus and produce humic and fulvic acids which bring the pH in the rhizosphere (the area immediately around the root) down to the required level. The pH in the soil can be very different from the pH immediately around the root system
Ferrous sulphate has fungicidal properties so applying it stops natural organic acid production and leads to thatch build up. A few kilos per hectare per year for cosmetic purposes is OK but if you look at any core taken from a rootzone that has had regular applications of ferrous sulphate over the years and you can immediately see the problems caused by the formation of iron bands, including anaerobic compacted layers, root breaks, sterile soil and black layer.
You are probably better off applying fulvic acid in spring and humic acid in summer as biostimulants mixed with liquid fertilisers – organic if possible and let the pH in the rhizosphere reduce naturally
1 Jul 2010 by chrismitchell Last edited 1 Jul 2010
Interestingly when I was at college many moons ago, in our soil science lectures we were told about how much lime had to be added to the fields on top of the south downs. Even though they are over chalk the soil became very acidic as nutrients including calcium leached out of the topsoil due to the very porous chalk below. That is the reason we see grasses such as fescues and bents on both downland and heathland, the soil over the chalk is acidic.
Chris
You will never see a statue in honour of a committee.
Phil
Plus, A lot of loams come in at that anyway due to it's structure (structured clay colloids with extremely high Cation Exchange Capacity) rather than a high sand which is essentialy unstructured. On my travels over the years I have seen some measurements of PH 8+ with perfect soil structures, roots and Ryegrass turf. As with all things, use PH as a guide and not in isolation.
AA
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