1911] The Ottawa Naturalist. 99 



THE FERTILIZING VALUE OF RAIN AND SNOW. 



By Frank T. Shutt, M.A. 



In the ascension and descension of water the continuous 

 rise of aqueous vapour from land and water surfaces, and its 

 interrupted fall as rain and snow we have natural phenomena 

 of the greatest importance to the maintenance of vegetable 

 and animal life on the earth. Some few years ago the writer 

 traced in a lecture before the Ottawa Field- Naturalists' Club, the 

 various ways in which this constant circulation of the world's 

 water supply affected our health and commerce, and how above 

 all it was necessary for the growth of our crops. As one of the 

 minor ways in which rain and snow contributed towards the 

 maintenance of plant life, it was pointed out that in their fall 

 through the atmosphere they cleansed it of certain nitrogen 

 compounds ammonia and nitrates gaseous compounds arising 

 from the combustion of fuel, from the oxidation of food in 

 animals, from the decomposition of nitrogenous organic matter 

 in the soil and from electric discharges in the atmosphere, and 

 it was further shown that these compounds brought down by 

 the rain and snow furnished to our crops a notable amount of 

 most valuable food. It was with the object of determining, 

 as closely as might be possible, the average annual amount of 

 available nitrogen so furnished per acre, that some years ago the 

 analysis of each fall of rain and snow was undertaken in the 

 chemical laboratories of the Experimental Farm, Ottawa. 

 This work has afforded interesting data, some of which may 

 now be presented. 



During the year ending February 28, 1911, the rainfall was 

 19.67 inches and the snowfall 73 .0 inches, a total precipitation 

 of 26.97 inches practically 10 inches below the average for 

 this locality- Omitting many of the details we may state that 

 this precipitation furnished 5.271 lbs. of nitrogen per acre. 

 This is about 1 lb. more than we obtained for the first year of 

 observation (ending Feb. 29, 1908), but markedly less than that 

 for the following year (ending Feb., 1909), viz. 8.364 lbs. per 

 acre. This latter we concluded was abnormally high and was 

 to be accounted for by the extensive bush fires which heavily 

 charged the atmosphere with smoke for at least two of the sum- 

 mer months in 1908. A summary of the four years' investigation 

 may be given in tabular form. 



