A new survey of Britain's soils has failed to confirm the loss of carbon between 1978 and 2007 reported by the 2005 National Soil Inventory, but agrees there has been a net loss of carbon from cropped land.
The Centre for Ecology and Hydrology's Soils Report from 2007 is part of the Centre's Countryside Survey and reports on ponds and headwater streams were published concurrently. The soils report has been carried out at intervals since 1978 and the 2007 survey looked in particular at soil carbon and a number of other issues such as the effect of the decline in atmospheric deposition of heavy metals.
On soil carbon, the report says concentrations increased between 1978 and 1998 and then decreased until 2007, resulting in no overall change.
The one consistent area of loss was in the intensively managed arable and horticulture broad habitat/crops and weeds aggregate vegetation class.
"This suggests that current policies in place to limit soil degradation are not maintaining soil quality in cropped land," it says.
Between 1998 and 2007, only small changes occurred in soil trace metal concentrations despite reported declines in atmospheric deposition and only one, copper, showed any significant change. It increased.
The paper suggests that where copper and cadmium has increased this could be due to manure, sewage sludge or compost application. Other metals may be declining due to cropping.
The report says the recovery in soil (0-15cm) pH detected by the Countryside Survey in 1998 has continued amongst the less acidic, mineral and humus-mineral soils suggesting recovery from acidification.
It says there were an estimated 12.8 quadrillion soil invertebrates present in the top 8cm of soils in 2007.
