THE FOREST NURSERY 245 



When nurseries are maintained for a long period of time on the 

 same site, it is well worth while to give the most careful attention 

 to thorough soil preparation. An expenditure of $100 or even 

 $150 per acre should not be considered excessive where the surface 

 is uneven or where stones and roots must be removed and deep 

 working is required. 



Under special conditions, the shallow working of the soil, even 

 in permanent nurseries, is preferable. This is particularly true 

 of nurseries where only small and surface-rooted plants such as 

 spruce are grown. Deep working may be harmful on soils that 

 are naturally loose and open and where the fertility is chiefly in 

 the surface layer. It is rarely advantageous in temporary nurs- 

 eries. 



16. DRAINAGE AND IRRIGATION 



Surface drainage should be perfect. The slope of the land 

 should be sufficient to carry off all surface water but not enough 

 to cause erosion. The site should be brought to a uniform grade 

 when it is relatively flat but with minor unevenness, so that water 

 will not stand in pools in the depressions. Springy slopes and low 

 flats where the water is near the surface should be drained by 

 means of open ditches or covered drains. Such sites, however, 

 should be avoided whenever possible. 



Irrigation is necessary in the conduct of nursery operations ex- 

 cept in the most favored localities and under .exceptional con- 

 ditions. Although some species can be grown -without irrigation 

 in regions of adequate precipitation for farm crops, an ample 

 supply of water very greatly reduces the cost of the stock, ma- 

 terially increases the size and makes success more certain. It is 

 particularly important that coniferous seedbeds be irrigated the 

 first year. 



The facilities for irrigation should be fully considered in locating 

 the nursery. The water may be obtained from a near-by spring, 

 stream or pond or from a well. The source of the supply should 

 be at a higher elevation than the nursery in order that the water 

 may be distributed by gravity. When the source is at a lower 

 elevation, the water is elevated to a reservoir or tank located on 

 the highest ground in the nursery, from which it is distributed by 

 gravity as required. . In small temporary nurseries no special 

 provision is usually made for irrigation, but water is brought by 



