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the altering of the physical condition of the soil. The principal 

 fertilizer in this class is lime. Lime is really a stimulant instead 

 of a plant food, and its continued use may be harmful or ex- 

 hausting to the soil. Air, water and heat are more necessary for 

 plant growth than mineral food. Production depends upon the 

 proper aeration of the soil, the maintenance of a proper water 

 content and through these two, the raising of the temperature of 

 the soil. These conditions add plant food in that they render 

 available the material that is stored away in soil compounds. The 

 control of moisture in the soil lies in the physical state of the 

 soil. If it is loose, porous, small grained, it will raise moisture 

 freely from the sub-soil and hold it where it will be available for 

 the plants and retard evaporation. The soil may be kept in such 

 condition by proper tillage and by the addition of such materials 

 as will effect a loosening and breaking up of the soil particles. 



Green manure is valuable and barnyard manure and charcoal, 

 with constant tillage, are among the best known agents. In using 

 barnyard manure the best part of the manure is often lost. A 

 large part of the mineral content is washed out if the pile is ex- 

 posed and the liquid portions leak out or escape in gases. Many 

 different substances have been tried for the purpose of prevent- 

 ing this loss. One of the very best matrials which can be used 

 for this purpose is charcoal. This is true because of its excep- 

 tional power of absorption, it possessing the capacity of absorb- 

 ing many times its own weight in moisture and also because its 

 physical effect upon the soil and the sub-soil has been conclusively 

 demonstrated. Charcoal is already extensively used as a deodor- 

 izer or disinfectant, and the fact should not be lost sight of that 

 the ammonia gas, which is quite lost in the manure heap, would 

 be absorbed by the charcoal and made available for plant use. 



For many years the attempt to raise coniferous seedlings in 

 this nursery was a comparative failure because of the hard clay 

 soil, which greatly increased the loss from unfavorable moisture 

 and surface conditions. Among the agents tried for the relief of 

 this condition were green manures, fertilizers and charcoal, and 

 of these only the last has ])roved successful, as may be observed 

 by the size and weight of seedlings developed from clay beds, 

 fertilizer beds or charcoal beds. The seedlings are much larger 

 and heavier and of better color on the charcoal beds than on any 

 other. Some fertilizer beds show good seedling development, 

 but the beds were not as densely covered with little trees as on 

 the charcoal beds, notwithstanding that the charcoal beds were in 

 the worst section of the nursery, while the fertilizer beds which 

 show the best weights were in sections cultivated for a longer 

 period. The charcoal seedlings averaged a weight of 250 grams 

 for a bundle of 100 trees, as against 127 grams for a check bed in 

 the .same grade of soil. These trees were two years old. At one 

 year the differences are not so striking, but are strongly marked. 

 One hundred seedlings from a clay bed weighed 22 grams, while 



