Drought symptoms on low pH unlimed Park Grass plot
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This photo was taken on 18 July 2005 and if I recall correctly it is showing in the foreground the unlimed (d) subplot of treatment 11/1 or 11/2 at Park Grass at Rothamsted. This treatment gets the highest rate of ammonium sulfate fertilizer and the soil pH in the unlimed subplot is less than 4. There is a large amount of thatch (or undecomposed plant material) at the soil surface, and the roots do not explore a large volume of soil. This creates chunks of turf that can be separated from the soil, and drought symptoms appear more rapidly because the roots do not access as much plant available water.
