INFLUENCE OF SEASONS. 23 



contains about the same per cent, of oxygen, nitrogen, car- 

 bonic acid, nitric acicl, ozone and ammonia. Tliese are what 

 we call atmospheric manures, or atmospheric elements of 

 nutrition. Now, then, the influence of the seasons upon 

 plant-nutrition must be this : its variable temperature, the 

 amount of water which falls, and the amount of sunshine 

 which acts upon the plant and upon the soil. Those are the 

 three conditions of the seasons which vary the amount of 

 plant-food that will be developed out of the soil itself or out 

 of the material which the farmer has given to the soil artifi- 

 cially. Thus, if we have a wet season, an extra quantity of 

 water-fall, which fills the interspaces of the soil so that the air 

 is excluded, so that warmth is excluded, the soil does not 

 become heated. Then the coarse, raw, undecomposed, unfer- 

 meuted mass of barn-yard manure, compost, muck, straw, 

 clover, or grain-crops ploughed in, remain dormant and dead, 

 and no nutriment is formed, and your plant starves for want 

 of food. If, on the other hand, your season is one of exces- 

 sive drought, little rain-fall, and the soil becomes dry, so that 

 decomposition stops, then your raw, crude material, your 

 barn-yard manure, and your muck, remain unchanged ; no 

 food is formed, and your plant starves for want of nutrition. 

 Now, then, the seasons have to do with the plant-nutrition in 

 just this way, and the farmer should have known that if he 

 would feed his plants, and do it thoroughly, with the varia- 

 tions of the seasons, he could not afford to trust them to make 

 plant-food out of raw or crude materials, but that it was a 

 part of his duty to prepare the food for his plants ere he com- 

 mitted it to the soil, and then the action of the season of 

 which he complains would have been entirely obviated, and 

 he could have produced crops yearly without regard to these 

 variations of the seasons which make maximum or minimum 

 crops. 



Now, gentlemen, having said this much, I am prepared to 

 say that it was to prove just this thing, among other subjects 

 connected and related to it, that a certain series of experi- 

 ments was entered upon at the Agricultural College some six 

 or seven years ago ; to prove that one thing, — whether cer- 

 tain elements of plant-food, prepared in the condition of 

 plant-food ready to nourish the plant, would not nourish 



