178 FORAGE PLANTS AND THEIR CULTURE 



177. Climatic adaptations. While orchard-grass is 

 strictly a temperate grass, it will withstand a greater 

 quantity of heat than timothy, and is also more easily 

 injured by winter cold.. In the United States, it is culti- 

 vated more abundantly southward than northward. This 

 distribution is due partly to competition with timothy and 

 partly from the fact that fall-sown stands of orchard- 

 grass are uncertain. This uncertainty has been ascribed 

 to late frosts rather than winter cold, but the evidence 

 is not satisfactory. Orchard-grass begins its growth in 

 spring much earlier than most grasses, which is one reason 

 why the late spring frosts are injurious. 



At Copper Center, Alaska, it was entirely winter-killed, 

 while a considerable percentage of timothy survived. 



At Fort Vermilion, Alberta, orchard-grass planted in 

 spring was completely killed the succeeding winter when 

 the minimum reached was 23 below zero Fahrenheit. 



178. Soil preferences. While orchard-grass will grow 

 in all types of soils, it ordinarily does not succeed well in 

 sands or muck. It is best adapted to clays or clay loams. 

 It is not averse to wet soils, but prefers a moderate amount 

 of moisture. Fair success can be had when the rainfall 

 is rather scanty, as it is somewhat more resistant to drought 

 than is timothy. 



179. Adaptation to shade. Orchard-grass succeeds so 

 well in shady places that this peculiarity has given rise 

 to one of its common names. Its adaptation to shade has 

 been ascribed as due partly to its great leanness and partly 

 to its early growth before the trees become leafy. How- 

 ever, it succeeds apparently as well in the shade of ever- 

 greens as of deciduous trees. 



Stebler in Switzerland shaded artificially one portion of 

 a field sown to a mixture of grasses and determined each 



