Having witnessed so many grade changes and top soil scrape offs I started to scan around the net. Just today I was on a site where the natural grade was down some 1.2m, compacted clay on top of shale. The excavator needed a rock breaker to go deeper. But this new grade will be ground level to everyone else, they'll have turf and concrete and never know better. When they plant trees they'll realise it's tough ground, and the trees will suffer. There was no top soil left on this site.
On another site they scraped it then spread a 100mm of new topsoil all over and put the turf in and few crappy little plants.
I bumped into this story. And liked it coz the ole euc is a tough customer, will live in absolute crap, however they didn't do too well here either.
Wiley InterScience :: Session Cookies Quote:
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Removal of topsoil, mainly for making bricks, is one of the main causes of soil loss around large urban centres of the Humid Pampa, Argentina. In about 7 per cent of La Plata County, the 20-40 cm thick A-horizon has been removed for that purpose. Most of the affected areas were originally prime farmland; however, with removal of the A-horizon they became unsuitable for agriculture, including grazing, since the exposed Bt-horizon is unsuited for plant growth due to its high clay content (45-65 per cent) and the low nutrient levels. Since trees survive better on poor soils than do agricultural crops, the possibility of afforestating desurfaced soils has been studied. Eucalyptus are one of the major species used in tree planting programmes aimed at reclaiming degraded soils since they are fast growing and can grow to commercial size in a wide range of soils and climatic conditions. The work reported here was done in a desurfaced Vertic Argiudoll and a similar non-desurfaced soil (control). Three Eucalyptus species were tested, i.e. E. camaldulensis, E. viminalis and E. dunnii. Their height and diameter (dbh) growth were 47.9 to 75.8 per cent less and timber volume 86.5 to 98.5 per cent less on the desurfaced soil. E. camaldulensis grew best in all the parameters in the desurfaced soil. Although tree growth was poor, afforestation may be an alternative use for desurfaced soils where agriculture and livestock breeding are not possible.
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