86 FARil GRASSES OF THE UNITED STATES 



soils, might replace it altogether. They are also bet- 

 ter adapted to sowing with clover, since they mature 

 at the same time that clover does. Spring sowing is 

 particularly objedUonable in the South, and the farther 

 south the more undesirable it becomes. In the first 

 place, spring-sown grass is likely to be taken by weeds, 

 especially by crab-grass. It is also liable to be killed 

 by the summer heat. 



On the northwestern prairies the best pradtice is to 

 prepare land in fall and sow grass and clover in spring 

 without a nurse crop. There is usually not moisture 

 enough for both grain and grass, while fall-sown grass 

 would hardly stand the rigor of the first winter. The 

 same is generally true on the irrigated lands of 

 W5'oming and Montana. On the upland prairies of 

 eastern Washington, eastern Oregon, and northern 

 Idaho, spring sowing is necessary, for during the win- 

 ter there are liable to occur periods of clear weather 

 in which the ground freezes at night and thaws in day- 

 time, a condition quickh* fatal to young g^ass. But 

 in this se<5tion the land cannot be prepared in autumn 

 with safety for two reasons : first, the winter rains 

 would wash it, for the country is quite roUipg; 

 secondly, the dry winds of early spring would quickly 

 rob the bare soil of its moisture, while a covering of 

 wheat-stubble prevents this. The best plan is to plow 

 the land in earl}' spring, harrow it down, and sow the 

 seed at once. At low altitudes in this sedlion, as 

 around Walla Walla and Pendleton, fall sowing is 

 successful. In western Washington, western Oregon, 

 and northern California timothy' is nearly always sown 

 in the fall. On sandy land in that section clover may 



