I plan to conduct a field experiment with maize and I am interested to
quantify the amount of N, P and K and perhaps other elements such as
heavy metals or acidifying agents during no rain periods (dry periods)
as well as periods of rain (wet periods).  I am therefore looking for
a procedure or a method to measure the deposits of these elements from
the atmosphere.  Can you please help me in this regard by giving me
any information you have about methods or instruments that can be used
for this purpose, or even if you know of any similar studies that have
been carried out.  I would also like to know the addresses of possible
suppliers of such instruments
 
Regards
Andre