Before planting, the ground was cleared of stones and scrub and ploughed to a depth of 30cm. According to the ultimate character of the planned phytoepisode, the soil was improved, to adjust the texture, organic matter content and pH value. The existing soil was mostly sandy, with an average pH of around 8.0, and the percentage of organic matter was very low, below 1 per cent. The original soil conditions, together with contamination in some areas from the former rubbish dump, and the acidic nature of many of the phytoepisodes to be represented, required some significant adjustment of the soils' conditions. It was also necessary to
cultivate the soils after the passage of much heavy machinery.
The standard correction applied to the whole site before inauguration consisted of the addition of a 15cm top layer consisting of 55 per cent coarse gravel, 20 per cent clay, 10 per cent mud and 15 per cent organic matter. Oversized tree pits (more than twice the root area) were used in order to improve planting conditions; these were backfilled with a mixture of 50 per cent coarse sand, 30-40 per cent plant-based organic matter, and 10-20 per cent animal manure.
Where more acidic conditions were required a standard specification was an 80cm-1m-deep planting bed, consisting of 10cm of drainage quarry rubble (30-70mm), 50-60cm of coarse sand, 10cm of sieved coarse sand, 20cm of a mix of 75 per cent sieved coarse sand and 25 per cent organic matter. After the soil improvement process, a conventional tree and shrub planting process was followed, together with the installation of an irrigation system.
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