SOILS AND FERTILIZERS 505 



In addition to its value as a green manure, crimson clover is 

 also important as a coyer crop, tending to prevent the leaching and 

 washing of soils, especially on hilly land. As a cover crop it is much 

 employed in orchards. For the improvement of poor lands in the 

 Middle Atlantic region there is no better plan than to use crimson 

 clover as a winter crop and cowpeas as a summer crop. 



Sweet Clover. This is a biennial plant, somewhat weedy in 

 character, which grows readily on almost all soils. It produces an 

 enormous root, and the tops often grow to a height of 4 or 5 feet. 

 Owing to the bitter character of the herbage it is not much liked by 

 stock, which have to learn to eat it. In a few sections of the country 

 it is grown as a hay crop. As a crop, sweet clover is most largely 

 grown in Alabama and Mississippi, where it is utilized both for hay 

 and for its improvement of the soil. It is considered at least equal 

 to red clover for the latter purpose. 



Owing to the ability of sweet clover to grow in the poorest of 

 soils, it will probably be found of high value in increasing their fer- 

 tility. The seed should be planted very early in the spring, using 

 about three-fourths of a bushel of the seed in the pod, the common 

 form in which it is found on the market. The greatest benefit will 

 be found in plowing it under the second season, before it blooms. 



In an experiment conducted at a German agricultural experi- 

 ment station sweet clover was sown in May with rye, seeding at the 

 rate of 21 pounds of hulled seed per acre. The following summer the 

 sweet clover was plowed under and followed with oats. The yield was 

 1,099 pounds per acre on plats where no sweet clover had been sown 

 and 1,645 pounds per acre where sweet clover had been used. 



Canada Peas. These are grown mainly in the northernmost 

 States and in Canada. As a winter green-manure crop in orchards 

 they have been used considerably of late years in California. Very 

 few accurate experiments have been conducted to determine the ef- 

 fect of Canada peas upon succeeding crops. In one such experiment 

 conducted at the Ontario Agricultural College wheat was grown on 

 three different plats on which peas, rape, and buckwheat, respectively, 

 had been plowed under. The yield of w T heat following Canada peas 

 was 36 1/10 bushels; following rape, 30 2/5 bushels; following buck- 

 wheat 26 3/5 bushels. There is here a clear gain shown in favor of 

 the Canada peas. The impression prevails among farmers in the 

 Canada pea belt of Michigan that oats following Canada peas yield 

 an increase of from 5 to 10 bushels per acre, but there are no ac- 

 curate experiments to substantiate this. At the Maine Agricultural 

 Experiment Station oats were sown on some plats following Canada 

 peas and on others following barley. On three out of four plats the 

 yield of oats was larger following barley than following the peas, 

 and the total of all the plats was much in favor of those that had 

 been in barley the previous year. No mention is made as to whether 

 the peas were tubercled or not. 



In a series of rotation tests at the South Dakota Agricultural 

 Experiment Station, extending over seven years, the effect of Canada 

 peas on the wheat was to increase slightly the yield of straw without 



