FOREST NURSERY PRACTICE 157 



If 

 tlon is variable, many seedlngs are of considerable heiglit before the last 



seeds germinate. If the mulch remains too long many seedlings are 



weakened and at times a considerable number are lost by being pulled 



when the mulch is removed. Ordinarily, the nurseryman must remove the 



mulch before the tardiest seed have germinated. 



Mulch is especially valuable in protecting seedlings from heaving 

 during winter and from drying out. As a soil cover it prevents as 

 serious freezing as would occur without it and especially assists in 

 controlling the alternate thawing and freezing that is so likely to cause 

 hoaxing. Mulch retards the growth in spring, for a period of 7 to 10 days, 

 but the seedlings are usually bleached to a slight extent. Many hay 

 mulches and possibly other muches are thought to increase the loss from 

 damping-off. 



In Colorado it was found that mulched seeds outside shade frames 

 germinate one to two days earlier than unmulched seed planted under 

 shade frames giving one-half shade. Mulching to uniform germination is 

 advised for very small seeds and for heeling in larger quantities. It is 

 thought that muching immediately after transplanting may have some 

 value in reducing loss. Leaf mulch is usually applied to a depth of two 

 inches, and is placed by hand, while straw is often applied to a depth of 

 four inches. 



Damping Ofif. 



Damping off has been especially bad on jack pine (pinus divaricatii) 

 in the nursery at Halsey but has also caused considerable damage with 

 other species and in other nurseries. It has not been infrequent to see 

 whole beds in which 90 per cent of the stand has been lost from this injury. 

 Spraying with Bordeau mixture, variations in watering, fertilizers and soil 

 covers have been tried without many conclusive results. Since last year 

 a forest pathologist has had charge of the experimentation at Halsey and 

 it is to be hoped that some satisfactory method of combatting this injury 

 may be devised. In Germany "schutte" has been largely limited by the 

 use of leguminous fertilizers. Numerous investigators have recommended 

 experiments in various degrees of light, degrees of air moisture, degrees 

 of soil moisture; fertilizers such as the legumes, commercial fertilizer 

 leaf mould, animal manures and ashes; and fungicides applied as sprays 

 nation is variable, many seedlings are of considerable height before the 

 could be accomplished without deterioration in other respects it would 

 be preferable to a method dealing only with the seedling. It is probbable 

 that there are several fungi which cause the damping off in which case 

 two or more remedies may be necessary in the same nursery. 



At Halsey, it was found that gravel spread over the bed after the 

 seeds were sown exerted a marked control. In beds where natural soil, 

 sand and gravel were used as surface layers the greatest damage 

 occurred in gravel. This was due to the gravel preventing an incrustation 

 of soil about the base of the seedling after rains or watering. However, 

 the remedy was not considered a good one becattse of the deterioration of 



