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ORCHAED GREEN-MANURE CROPS IN CALIFORNIA. 



during the cool weather of the winter, thus affording a heavier growth 

 to be turned under. This is an especially strong point where it is 

 desirable to turn the crop under as early as possible, as is the case in 

 the citrus orchards of southern California. The plants referred to 

 are the black-purple vetch, the black bitter vetch, the woolly-podded 

 vetch, the horse bean, and the Tangier pea. 



BLACK-PURPLE VETCH. 



The black-purple vetch (Vicia atrojmrjmrea) is one of the most 

 promising green-manure crops tested for California. Its general 



Fig. 7.— a field of black-purple vetch at Chico, Cal. 



appearance and habit of growth are about like those of the com- 

 mon vetch (fig. 7), although it is very distinct from that species. 

 The superior value of black-purple vetch when compared with com- 

 mon vetch lies in its ability to make a much stronger growth during 

 the cool weather of early winter. This, as noted elsewhere, is an 

 especially desirable quality in a green manure to be turned under in 

 February, 



The root system of black-purple vetch, which is similar to that of 

 common vetch, is well covered with medium large nodules. The 

 stems, aside from making a strong growth, are of such a texture as 



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