High in warm wet=tropics
low in cool dry + tundra or desert
increases with evapotraspiration.
LieBig's law growth is limited to limiting reasoure the barrel analogy
ex: nitrogen often limits photosynthesis
casued from weathering
P decreases over time and are very low in old highly weathered soils.
ex: high in temperate adn decreases in old tropics so does the organic line
wet id precip. and fog /cloud ex is dissved HNO3
dry is dust and gases ex is SO4 aresols
breakdown of organic matter
CO2 = H2O yeilds CH2O = O2 is photosynthesis and reverse is decomp.