P. Ineson et al., EFFECTS OF CLIMATE-CHANGE ON NITROGEN DYNAMICS IN UPLAND SOILS - 1 - A TRANSPLANT APPROACH, Global change biology, 4(2), 1998, pp. 143-152
The impact of climate change on N leaching from hill land plant/soil s
ystems was investigated using a transplant technique involving the mov
ement of intact lysimeter cores of three contrasting soil types down a
n altitudinal gradient at Great Dun Fell, Cumbria. Air and soil temper
atures and precipitation were monitored at four elevations down an alt
itudinal transect using automatic weather stations for a period of two
years. The altitudinal sequence of air temperature followed the antic
ipated pattern, providing mean annual temperatures at the four locatio
ns of 3.4, 5.0, 6.3 and 8.1 degrees C. Lapse rates of both mean air an
d soil temperatures over the altitudinal range 171-845 m were 6.6 (199
3) and 7.0 degrees C km(-1) (1994). Soil monthly temperature gradients
for a particular soil type for each of the two years showed a seasona
l range of 6.0 and 7.4 degrees C km(-1), respectively, and for air tem
perature of 4.3 and 3.1 degrees C km(-1). Precipitation gradients show
ed the expected general increase with altitude, but were less predicta
ble. Inorganic nitrogen leaching was studied in lysimeter leachates wi
th climatic amelioration resulting in dramatic reductions in leachate
nitrate concentrations and associated total concentrations of inorgani
c nitrogen. Decreases in leachate nitrate concentrations were observed
for all three soil types studied. Soils receiving supplemented rainfa
ll also showed decreased N concentrations, suggesting that temperature
was the main controlling factor responsible for the observed reductio
ns. Increased N uptake by the vegetation, in response to the increases
in temperature, is considered to be critical in controlling soil solu
tion chemistry at these sites.