I 88 CLOVERS 



where water is excessive, in a climate which in win- 

 ter or spring is characterized by alternations of 

 freezing and thawing, the plants will either have the 

 roots snapped asunder, or they will be gradually 

 raised out of the ground. This will only happen 

 in soil with a subsoil more retentive than is com- 

 patible with well-doing of the highest order in the 

 plants. The danger from this source is greatest 

 during the first winter after sowing the plants, as 

 then the roots are not really established. The only 

 remedy for such a contingency is the draining of 

 the land. 



Some reference has also been made to injury 

 done through ice, where it collects in low places in 

 land. The destructiveness of the ice depends on 

 its thickness and its nearness to the ground. When 

 it rests upon the ground for any considerable time 

 the plants die. If, however, water intervenes, the 

 plants may live when the submergence is for a lim- 

 ited time. One instance is on record in Onondaga 

 County in New York State, in which alfalfa sur- 

 vived submergence for a considerable period under 

 a thin sheet of water covered by three inches of 

 ice, but when growth came it was for a time less 

 vigorous than normal. 



Floods in warm weather are greatly injurious to 

 alfalfa. The extent of the injury done increases 

 with increase of depth in the waters of submergence, 

 increase in stagnation in the waters, and increase 

 in the duration of the period of overflow. Stag- 

 nant water sooner loses its dissolved nitrogen; 

 hence, the plants cannot breathe normally. The 



