NURSERY PRACTICE FOR PRAIRIE-PLAINS, PLANTING 



17 



The pulp and light seed will be brought to the surface and spill over the 

 edge of the tub as the water overflows. With some experience, this 

 simple technique is quite effective. 



SEED DRIER 



A rotary seed drier developed by the Forest Service is a convenient 

 aid in drying seed following extraction, especially during winter 

 months, when outside air drying is not feasible and inside drying space 

 is limited. The drier (fig. 7) consists of a screen-wire cylinder 32 



Figure 7. — Rotary seed drier with power hook-up. 



inches in diameter and 32 inches long with wooden ends of Vinch 

 lumber. The three 1- by 3-inch baffle boards, equally spaced within 

 the periphery of the cylinder, pick up the seed as the drum revolves 

 and slowly spill it in a thin stream as each baffle reaches the highest 

 point. Warm air from a heater, forced through the revolving cylinder 

 by an electric fan. hastens the evaporation of moisture from the seed. 

 The optimum speed for the cylinder is 12 to 15 r. p. m. 



This machine dried 20 pounds of redcedar seed in one hour's opera- 

 tion, whereas the seed of the same quality placed on screen wire trays 

 dried only slightly after a week's exposure in the same room. There 

 is danger, however, in too rapid or excessive drying. This is brought 

 out in connection with dry storage. 



EXTRACTION FACTOR 



Considerable loss in weight generally occurs from drying and from 

 the removal of pulp, pods, twigs, and other debris. Very seldom will 

 the extracted weight of good seed approach the collecting weight. 



29787! 



