§ Malcolm BruceTo ask the Secretary of State for Environment, Food and Rural Affairs if she will supply data from the National Soil Inventory, using the average figure of all arable sites measured, on the change in(a) soil depth, (b) pH level, (c) nutrient level and (d) heavy metals between the 1978 to 1981 survey and 1994 to 1996 soil survey. [44728]
§ Mr. MorleyThe National Soil Inventory can supply no data on changes in soil depth. Data on the other variables requested are not available at "arable sites" level, but data on arable/ley grassland sites are given in the following table.
Arablie/ley grassland sites Variable 1978–81 1994–96 Change (b) pH 6.76 7.12 +0.36 (c) nutrient level (i) organic carbon (percentage) 3.27 2.79 -0.48 (ii) available phosphorus (mg/1) 31.81 41.45 +9.64 (iii) available potassium (mg/1) 199.19 236.01 +36.82 (iv) available magnesium (mg/1) 141.78 143.80 1— (d) heavy metals total zinc (mg/kg) 88.64 68.30 -20.34 total copper (mg/kg) 20.24 18.27 -1.97 total nickel (mg/kg) 27.05 24.45 -2.60 total cadmium (mg/kg) 0.80 0.32 -0.48 total lead (mg/kg) 41.46 36.21 -5.25 total cobalt (mg/kg) 11.58 10.94 -0.64 total chromium (mg/kg) 43.82 35.08 -8.74 total arsenic (mg/kg) 4.22 5.36 +1.14 total mercury (mg/kg) 0.06 0.12 +0.06 total selenium (mg/kg) 0.43 0.40 1— total molybdenum (mg/kg) 0.94 0.69 -0.25 total vanadium (mg/kg) 47.77 44.05 1— 1 The change is not regarded as significant in statistical terms. Note:
"Available" means concentration in extractant.
Source:
SSLRC (2000)—Comparison of original and resampled national soil inventory data. DEFRA R&D Project SP0506, Final Report.