498 MISCELLANEOUS FARM SUBJECTS 



It is, of course, well known that other causes than the removal 

 of plant food may reduce the productivity of the soil. Such causes 

 as sour soil, the deleterious effect of one crop upon the succeeding 

 one, and poor tillage may and often do result in poor crops. These 

 causes are, however, largely within the control of the farmer and in 

 no way affect the general statements above made. 



The feeding of crops, taken as a whole, is necessarily limited 

 by the total demand for live stock. The total number of live stock 

 required to supply the market demands can furnish but a small pro- 

 portion of the manure needed. On this account the practical use of 

 barnyard manure is naturally limited to regions where animal hus- 

 bandry is prominent. Where stock raising is but little developed 

 recourse must be had to other fertilizers. It is primarily in such 

 regions that the use of green manures is necessitated. 



Orchard Cover Crops. The term "cover crops" was originally 

 used to include crops grown for various diverse purposes, such as to 

 prevent soil washing, to hold drifting snow, for keeping the soil 

 warm in winter, and to hasten the ripening of wood. As these crops 

 were used largely in orchards and as they were often legumes, so 

 that they might serve also as green manures, the term cover crop is 

 frequently used to include crops grown in orchards primarily for 

 green manure. 



The growing of leguminous crops in orchards is generally con- 

 sidered excellent practice, except in dry regions where irrigation is 

 impracticable. In the citrus orchards of southern California a num- 

 ber of different legumes are used as winter cover crops ; among them 

 Canada peas, common vetch, hairy vetch, and fenugreek. Besides 

 these, many others have been tried in an experimental way, such as 

 horse beans, scarlet vetch, black-purple vetch, lupines, sweet clover, 

 and berseem. The two first mentioned are most used at present, and 

 the general opinion is that the practice is decidedly profitable. There 

 is, however, a lack of accurate data on this point. Some orange 

 growers are also using cowpeas as a summer cover crop. 



In Delaware and other States" of the Atlantic Seaboard, crimson 

 clover is the most common legume used as a cover crop. To a less 

 extent common vetch and hairy vetch are employed. At the Ohio 

 Agricultural Experiment Station it was found that apple trees grew 

 more rapidly and yielded larger crops when the orchard was kept in 

 grass. After each mowing the straw was used as a mulch about the 

 trees. Where the trees were cultivated in a circle of 3 or 4 feet 

 about the base, the results were distinctly inferior. Clean summer 

 culture with a winter cover crop gave results intermediate between 

 the other two. 



It is probable that the best results in different portions of the 

 country will be obtained by different methods. There is much need 

 of determining accurately the results of different treatments as 

 shown both by the growth of the trees and the crop produced. 



Crops to Follow Green Manures. The plowing under of large 

 quantities of green herbage, especially when this is done during the 



