328 FOE AGE PLANTS AND THEIR CULTURE 



region between the meridian of 98 and the Appalachian 

 Mountains ; five to fifteen pounds on unirrigated, semi- arid 

 lands, depending on the amount of rainfall ; fifteen pounds 

 on irrigated lands. 



Provided a good stand is secured, a low rate of seeding 

 is just as satisfactory as a high rate. At Lethbridge, 

 Alberta, alfalfa was seeded at the following rates on irri- 

 gated land : 5, 10, 15, 20, 25, 30 pounds an acre. The 

 average yields for 3 years were, respectively, 10,273, 11,333, 

 11,426, 11,220, 10,875 and 11,394 pounds an acre. 



392. Time of seeding. Alfalfa is sown either in the 

 spring or in late summer or early fall, depending on cli- 

 matic and other conditions. In the irrigated lands of the 

 West, spring seeding is most frequently practiced, but fall 

 seeding is just as successful. On unirrigated lands in the 

 West, the time is usually determined by the moisture 

 conditions of the soil. In the Great Plains region, this 

 is usually best in spring, while in the intermountain 

 region, spring seeding on fallow land is a common practice. 

 In states with very cold winters spring or early summer 

 seeding is necessary, as fall-sown stands are likely to be 

 winter-killed. Where the winters are not severe, and mois- 

 ture conditions permit, late summer or early fall sowing 

 is preferable. The sowing should be early enough to 

 permit the alfalfa plants to become well rooted by winter ; 

 otherwise, serious losses may result from heaving; and 

 late enough so that summer weeds especially, crab- 

 grass and pigeon-grass will - not seriously affect the 

 stand. In the Northern States, winter-killing is the most 

 serious difficulty in securing a stand of alfalfa, while south- 

 ward, weeds become the principal factor. From an 

 economic standpoint, fall sowing in the East is also prefer- 

 able, as a good crop is secured the next season, while with 



