NURSERY PRACTICE ON THE NATIONAL FORESTS. 3 
When the spray falls in a 10-foot radius, this equals from 1.3 to 1.9 
inches of rainfall per hour. It may occasionally be necessary to use 
10 or 12 sprinklers at one time, which means that there must be avail- 
able at least from 40 to 75 gallons of water per minute. 
SOIL. 
In choosing the location for a nursery, soil possessing the best 
chemical and physical properties should be selected. Forest Service 
experience has not indicated that it should resemble the soil of the 
planting site, especially where that is poor. Plants grown in poor 
soil, particularly dry soil, are forced to extend their roots in search 
of moisture ; and when such plants are removed from the nursey the 
fine feeding roots are almost certain to be cut off and the stock ren- 
dered less fit for field planting. Thrifty plants with a normal root 
development grown on good soil generally offer the best chance for 
success. 
The soil should be sufficiently fertile ; but desirable physical quali- 
ties, such as moderate freshness, friability, and depth, are of more 
importance than chemical ones, since the latter may be more easily 
changed through the use of fertilizers than the former. 
A soil with a sandy foundation, particularly a sandy loam, is 
better suited for nursery operations than one with a clay or limo 
foundation (see PI. I). The latter dries out and warms up slowly 
in the spring, delaying nursery operations and retarding the growth 
of the plants; it freezes and heaves much more decidedly than the 
former; it is more difficult to work in plowing, cultivating, and 
transplanting operations; the roots skin more when the trees are 
dug; it forms a hard surface and cracks upon drying; seedlings 
sometimes have difficulty in pushing through it ; the development of 
the fine, lateral roots is not so good as in lighter soils; and weeds 
obtain a much firmer foothold. On the other hand, a soil extremely 
light, sandy, or loose should be avoided because of the rapidity with 
which it dries out, the too extensive and undesirable root development 
which it fosters, and the danger of general unthriftiness of the 
plants. 
If the surface soil is a good, fairly moist, retentive, sandy loam, 
the deeper it is the better. Where it is deep there will be an abundant 
supply of fertility upon which to draw, the infertile subsoil will not 
be disturbed by plowing and mixed with the other soil, and the soil 
conditions will be ideal for the development of excellent stock. A 
very desirable combination is good, porous surface soil from 3 to 4 
feet in depth, underlaid by a more retentive subsoil. Such a sur- 
face soil is of sufficient depth to allow the necessary drainage; and 
as moisture is needed it can be drawn from the retentive subsoil 
