XIV
Contents
14
Precipitation Chemistry and Air Pollution
A. Escarre, A. Carratahi, A. Avila, J. Bellot, J. Pinol, and M. Millan .... 195
14.1 Introduction ........................................................................................... 195
14.2 Bulk Precipitation Chemistry at Prades and Montseny .................... 196
14.3 Geographical Patterns .......................................................................... 198
14.4 Sources of Ions in Precipitation ........................................................... 199
14.5 The Airshed ............................................................................................ 200
14.5.1 Back Trajectories and Origin of Air Masses ....................................... 200
14.5.2 The Iberian Low System, Stratification
and Recirculation Processes .................................................................. 202
14.5.3 Secondary Pollutants and Their Potential Effects .............................. 202
14.6 Long-Term Trends in Precipitation Chemistry .................................. 203
14.7 Relevance of the Atmospheric Inputs
to Ecosystem Nutrient Cycles............................................................... 205
References .......... ............. ........................ ................................ .... ....... ............... 106
15
Throughfall and Stemflow
J. Bellot, A. Avila, and A. Rodrigo ......................................................... 209
15.1 Introduction ........................................................................................... 209
15.2 The Database ......................................................................................... 210
15.3 Throughfall and Stemflow Hydrology ................................................ 212
15.4 Nutrients in Throughfall and Stemflow .............................................. 214
15.5 Net Inputs and Sources of Nutrients
in Throughfall and Stemflow ............................................................... 218
References ......................................................................................................... 220
16
Soil Nitrogen Dynamics
1. Serrasolses, Y. Diego, and D. Bonilla ................................................. 223
16.1 Introduction ........................................................................................... 223
16.2 Total Nitrogen and C:N Ratio in the Soil Profile ................................ 224
16.3 Soil Mineral Nitrogen ........................................................................... 225
16.4 Nitrogen Mineralization ....................................................................... 227
16.5 Nitrogen Leaching ................................................................................. 229
16.6 Ecosystem Nitrogen Availability .......................................................... 232
References ......................................................................................................... 233
17
Soil Water Chemistry
N. Melia, J. Bellot, and Y.R. Vallejo ....................................................... 237
17.1 Introduction........... ............. ......... ....... ........ ................... ......... ............... 237
17.2 Gravitational Water ............................................................................... 238
17.2.1 General Characteristics and Variations Within the Soil Profile ........ 238