402 THE MONTHLY BULLETIN. 



Our results show that from a twelve ton yield of Melilotus clover, 

 we have obtained an effect equal to that resulting from an application 

 of from five hundred to one thousand eight pounds of nitrate of soda 

 to the acre, costing from twelve dollars to thirty dollars. This fact 

 certainly warrants the careful consideration of the agriculturist, and 

 in particular he who is interested in citrus culture, where intensive 

 fertilization is so generally practiced. 



One other important item is covered by this experiment. That is in 

 regard to the comparative merits of the various legumes used. 



New Legumes. 



Several new legumes have lately been introduced by the Bureau of 

 Plant Industry of the Department of Agriculture, two of which are 

 very promising. These are the Tangier pea and the purple vetch. The 

 Tangier pea is of very vigorous growth and in the five years average 

 exceeds all others in tonnage of green tops produced. It has also given 

 marked increases in yield of field crop following incorporation of 

 tops with soil, and is in many ways a valuable acquisition to the green 

 jnanure crops. It has, however, one great fault. The seed is very 

 difficult to produce, as the pods burst and shatter the peas very badly 

 when ripe. Professor McKee of Chico, who has been working with 

 this variety for some time, believes the seed of this pea may never be 

 produced cheaply enough to be used as a covercrop in citrus orchards. 

 At present, the seed is not available in commercial quantities. The 

 other variety mentioned above, the purple vetch, had only been grown 

 by us for two years and but once in our regular plat experiment. It 

 has, however, yielded a wonderful tonnage of green tops per acre and 

 grows more rapidly in the fall than any other legume tried. It is 

 aphis resistant and so vigorous that weeds have absolutely no chance 

 to develop with this vetch. 



Professor ]\IcKee has been working on this vetch for several years 

 and has been able to establish the seed growing of this variety in 

 Oregon, and this year (1914) for the first time a limited quantity of 

 this seed will be available for commercial planting. 



The fact that we have not had a field nitrogen test of this crop makes 

 it impossible for us to say just how this crop will compare with the 

 others we have tried, but the features, such as aphis resistance, rapid 

 and early fall growth, and its weed proof nature, make it a plant 

 worthy of extended trial by citrus growers and all others interested 

 in green manure crops. 



Of those varieties which we have tested thoroughly, none gives such 

 promise as does the Melilotus or sour clover (Melilotus indica). This 

 variety has given the largest increase in the crop following and for 

 soil types similar to the decomposed granite soil of this station, we 

 believe it will be hard to equal. 



It grows very well on the heavy red soils of West Riverside and in 

 its wild state seems adapted to quite different soil types. For this reason 

 this clover is worthy of trial in all citrus sections. Sow about thirty- 

 five pounds of seed to the acre (acre solid land; reduce when trees 



