New York AGRICULTURAL EXPERIMENT STATION. 175 
HEAVING. 
Considerable damage is done by the so-called “ heaving” of the 
plants which is quite as common with alfalfa as with red clover and 
due to the same cause, alternate freezing and thawing when the 
surface layer of the soil is filled with water.® Newly seeded fields 
suffer most, but fields of any age may be affected. This trouble 
was unusually common and severe in New York in the spring of 
1904. Prof. Stone’ says: ‘‘ About the first day of May [1904] 
the writer’ saw fields of alfalfa of the previous spring’s seeding 
where three-fourths of the plants were thrown out upon the sur- 
face of the soil so completely that they could be gathered up by 
handfuls like so much straw.” 
The effects of heaving are best observed during the latter part 
of April. It is most severe in the wetter portions of the field. 
Sometimes nearly all the plants are killed out over large areas the 
boundaries of which are fairly well defined, but the trouble is more 
likely to take the form of thin spots of irregular shape and indefi- 
nite outline. In mild cases, when only a few affected plants are 
scattered here and there each spring, the trouble may pass unnoticed 
until in the course of a few years the alfalfa becomes “ run out.” 
The plants may be lifted completely out of the ground and left lying 
on the surface or they may remain standing with one to four 
inches of the tap-root exposed. If the plants are lifted as much as 
four inches death usually results; in less severe cases recovery is 
frequent although the plants never regain their normal position and 
the foliage. 
Thorough drainage is the approved remedy for heaving. How- 
ever, there are instances in which the drainage is apparently good 
yet the land heaves. Such a case is mentioned by Watson.® 
HARDPAN. 
Most writers on alfalfa regard the character of the subsoil as 
very important. Miller® says that “the subsoil seems to be the 
controlling factor in the successful growing of alfalfa in Missouri.” 
Where the subsoil is of the hard, impervious kind known as hard- 
pan, alfalfa is not likely to succeed unless the land is very thor- 
oughly underdrained and other conditions are favorable. Doubtless, 
°A discussion of heaving is given by Sorauer (97, 1:65). 
™Stone (99, p. 6). 
*Watson (106). ; 
*Miller (66, p. 13). ; 
