PLANTS OF THE CLOVER FAMILY. 77 



especially where the soil contains much clay. The 

 winter rains cause it to "run together" in a way that 

 increases the labor of subsequent cultivation, and 

 that further imperils the abundant and vigorous 

 growth of the plants. Some soils are so friable that 

 they call for but little pulverization; other soils, as 

 clays, are oftentimes cloddy on the surface. It is 

 especially important that these shall be made fine by 

 the repeated use of the roller and harrow. Firmness 

 in the seed bed may be secured by plowing the land a 

 considerable time previous to the sowing of the seed, 

 or by using the roller freely on it. Autumn plowed 

 lands always furnish a seed bed more firm than those 

 that are spring plowed, a fact of much significance 

 in cultivating the soils of the northwestern prairies. 

 When firming some classes of these soils, by running 

 a heavy roller over them, it may be necessary to 

 follow the roller with a light harrow to prevent them 

 being more or less carried away by the wind. Deep 

 cultivation is secured, of course, by simply plowing 

 more deeply, and in some instances by subsoiling. 



In some sections of the prairie the growth of 

 clover is greatly promoted by plowing so deeply that 

 some of the firmer subsoil shall be brought to the 

 surface. But with nearly all classes of soils, if much 

 of the subsoil were brought to the surface at one 

 time the influence on plant growth at the first would 

 be harmful, because of the unameliorated condition 

 of such subsoils. The management that secures a 

 fine tilth and a firm seed bed will also tend to increase 

 the moisture in the land. When the clover seed is 

 sown early in the spring, a clean seed bed can only 

 be secured by cultivation given the previous season, 



