GRASSES AND FORAGE PLANTS. 207 



&quot; Clover Sickness.&quot; When soils have for a series of years borne luxuriant crops 

 of clover, it sometimes happens that they seem suddenly to be unable to continue its produc 

 tion longer, which is evinced by the plant being found stunted in growth and scattered here 

 and there in small patches, surrounded by the bare soil. Sometimes the plant has a yellowish 

 tinge and is covered with brown spots, which are found to be a minute cryptogamic parasite. 

 AVhen these indications occur, the land is said to be &quot;clover sick.&quot; 



The cause of this disease is not fully understood, various opinions being entertained re 

 specting it. It is the general opinion, however, that one of the chief causes of the evil is the 

 exhaustion from the soil, by the continual growth of the clover crop, of some of the elements 

 which are essential to its growth. 



Dr. Grouven, after a careful study of this subject in Germany, arrived at the conclusion 

 that the chief cause of the clover disease is attributable to a change in the chemical composi 

 tion of the plant, which change is caused by an altered condition of the soil. The difference 

 between the composition of the ash of healthy and diseased clover is seen by the following 

 analysis, which shows in the latter a remarkable deficiency of potash and phosphoric acid: 



Health} clover. Diseased clover. 



Wolff. Grouven. 



Potash 35.5 3.22 



Soda ....... 0.7 0.87 



Lime 32.8 55.71 



Magnesia . . . . . . . 8.4 13.08 



Chlorine 3.5 2.76 



Sulphuric acid . . . . . . 3.3 13.46 



Phosphoric acid . . . . . . 8.4 5.99 



Silicic acid 7.0 4.88 



99.6 100.07 



Prof. Buckman refers, in connection with this subject, to the fact that our clover is a 

 derivative plant that has been forced in growth until it is now many times larger than the 

 wild plant from which it sprung, and that this growth demands the continuance of those ele 

 ments from the soil which were originally the cause of its enlarged growth ; hence the lack of 

 a sufficient supply of those elements may be one of the causes of the disease. Insects injurious 

 to clover are constantly increasing, and this may be one of the causes of the evil. It has been 

 found that one of the best remedies in this disease yet discovered is paring and burning the 

 surface of the soil, which destroy the eggs and larvae of insects injurious to it, and also all 

 the undecomposed vegetable matter that it may contain. A rotation with other crops, for a 

 sufficient length of time to change the properties of some of the constituents of the soil, will 

 also prove highly beneficial. 



Alsike Clover, (Trifolium hybridum.) This plant is a native of Sweden, and is often 

 known by the name of &quot;Swedish clover.&quot; It is said to have been brought from Sweden 

 to Scotland by a professional land-drainer of Edinburgh, Mr. George Stephens, and sown in 

 the Meadowbank nursery on the 17th of April. It blossomed on the 25th of August, and 

 the seeds ripened in the early part of the following October, when the plant was twenty-two 

 inches high. In the year 1835, the plants were in full flower on the 18th of June and ripened 

 their seed in the early part of August, when the plant was about two feet high. From 

 thence it spread gradually into England and was introduced into the United States about the 

 year 1855, where in some portions it became quite popular. It is a perennial, and endures 

 for a longer or shorter time, according to the character of the soil; on good soils it will do 

 well for four or five years. It is more like the white clover than the red, in its growth and 

 blossom, and is considered a valuable addition to the forage crops. The color of the flower 

 is white with pink markings when fresh blossomed, but which fade out to white before drop 

 ping. The general appearance of the stem is more smooth than that of the red clover. The 



