GRASS AND HAY 73 



great many different causes of clover failure. In Europe this term 

 is used to designate the condition of the land when it fails to grow 

 continuous crops of clover but which will again grow successful 

 crops after an interval of five to eight years. Such a condition would 

 appear to be due either to the exhaustion of some particular element 

 of fertility required by the clover, which would again become grad- 

 ually stored up in the soil during the years when no clover was 

 grown, or to the presence of some deleterious substance left in the 

 soil by the clover plants, which is gradually eliminated from the 

 surface layers of the soil. 



Many sections in this country no longer grow clover as easily 

 as it was formerly grown. Observations indicate that this failure 

 to produce successful stands of clover is not due to any one particular 

 cause but rather to a number of different causes, any one or any com- 

 bination of which may react very unfavorably on the stand of clover. 

 In some sections the cause of the frequently noted failures with 

 clover has been specially determined. In Tennessee the presence 

 of the clover anthracnose disease appears to be the principal feature 

 in working against the production of this crop. In Illinois the lack 

 of phosphorus and lime in the soil (often in connection with lack 

 of proper drainage) has been pointed out as a predisposing cause 

 of failure to get stands of red clover. In West Virginia the presence 

 of nematodes on the roots has been observed to react unfavorably 

 on the stands. In other sections failures have been shown to be due 

 to lack of sufficient quantities of lime in the soil. (Farmers' Bulle- 

 tin 455, 1911.) 



Varieties of Red Clover Ordinary. There are a number of 

 varieties of red clover, each more or less adapted to some special 

 purpose or to certain sections. Red clover (Trifolium pratense) is 

 the most important member of the group of true clovers, although 

 there are other important varieties and species. Under conditions 

 where red clover succeeds it is the best general-purpose clover. It 

 will usually produce both a crop of hay and a succeeding crop of 

 seed in the same season. It has the furtner advantage of succeeding 

 under ordinary conditions when seeded in connection with a grain 

 crop, thus calling for very little extra labor when it is desired to 

 establish a stand on the farm. 



Mammoth Clover. Mammoth clover, also known as Sapling 

 clover, Pea Vine clover, Bull clover, and Perennial clover, is only 

 a form of the ordinary red clover and is not sufficiently distinct 

 botanically from Trijolium pratense, the ordinary red clover, to 

 receive a botanical varietal name. It is not the "zigzag clover" of 

 northern Europe, known as Trijolium, medium, which latter name 

 has often been misapplied to Mammoth clover. Mammoth clover 

 is about two weeks later in maturing than the ordinary red, and it 

 is partly owing to this fact that it is impracticable to harvest both a 

 hay crop and a seed crop the same season. Mammoth clover is 

 useful in seeding with timothy for hay, because it and the timothy 

 bloom at the same time, whereas ordinary red clover blooms too 

 early for the best results in cutting the timothy. The large size 



