in the use of smaller quantities. Furthermore, the soil con- 

 ditions are exceptionally bad in this nursery. 



From constant observation and experiment, the action of 

 charcoal that makes it so valuable in the nursery seems to 

 be entirely in the improved conditions of moisture and 

 warmth. It might be thought that charcoal would loosen he 

 soil to the extent that it would dry easily if used in large 

 quantities, but the opposite condition occurs. In dry periods 

 the power of the soil to retain water is increased, and in wet 

 seasons the soil drains quickly with a consequent prevention 

 of fungus that always follows a wet season in a coniferous 

 nursery. The clay beds, by reason of their caking habit in 

 dry weather, and poor drainage in wet weather, exerted the 

 opposite effects and the loss was much more marked. In 

 some cases it was complete. Again charcoal beds are much 

 warmer, because of the darker color imparted to the soil. 

 This is . of the greatest importance in the spring, when the 

 ground has a tendency to be cold. Germination is almost 

 entirely dependent on the warmth present and is consequent- 

 ly greatly helped by the darker color of the soil. Since the 

 darker colored soil does not radiate any more rapidly at 

 night, this heating effect is carried forward into the night 

 and lessens the liability of damage from frost. In gardens 

 and hot beds, this is of considerable importance. This in- 

 creased heat is of value in another direction. The aeration 

 of the soil depends upon the heating and it will be greater 

 in the soil which becomes warmer during the day. 



Thus we find that the action of charcoal in the soil is ex- 

 erted along the lines where the most can be accomplished. 

 The physical conditions of the soil are so improved that the 

 air, heat, and moisture coming to the crop is regulated in the 

 most advantageous manner, and, mechanical analyses of the 

 sub-soil have shown that the charcoal exerts a beneficial ac- 

 tion at a considerable depth, twelve to eighteen inches below 

 the surface. The sub-soil beneath charcoal beds is of a bet- 

 ter color and better physical structure than soil from the sur- 

 face of untreated beds. This means an increase in the water 

 holding power, and a breaking up of unavailable compounds 

 into available plant food. 



8 



