Chlorine is added to soil from a wide variety of sources that include chloride from rainwater, irrigation
waters, animal manures, plant residues, fertilizers, and some crop protection chemicals. The
amount of chloride deposited annually from the atmosphere varies from 18 to 36 kg-1
for continental areas to more than 100 kg-1
for coastal areas (4)
. Most of the chloride
applied as animal manures or plant residues is soluble and readily available for crop uptake.
Because most of the chloride in animal manure is probably present in the liquid fraction, manure
management and handling may influence the concentration of chloride.