LEGUMINOUS CROPS IN NORTH CAROLINA 



By T. B. Parker. 



The aggressive campaign that has been waged for the past few years 

 in the interest of better farming by the use of legumes has not been 

 without its reward. As farmers have become better acquainted with 

 these crops and as they have more fully understood their economy in 

 crop production, the greater has grown the demand for information 

 about them. Nor is this surprising, for when we recognize the value 

 of cover crops, and the advantage of legumes as cover crops, as pre- 

 venters of erosions, conservers of plant food which might otherwise be 

 leached out of the soil; and, also their power to add to the supply ot 

 plant food, deepen the soil and add to its supply of humus; to improve 

 its physical condition, and, in addition, their value as hay and grazing 

 crops, to the progressive farmer they become very interesting. But to 

 properly perform the functions of a winter cover crop, those adapted to 

 that purpose should be sowed sufficiently early to so cover the soil 

 before their growth is stopped by cold weather as to protect \t from 

 erosion. But when they are sowed even too late for that, their root 

 system may make enough growth to stop a large part of the waste of 

 plant food that would be leached out of a bare soil. Then it is a well 

 known fact that of the three essential elements in plant food, nitrogen, 

 phosphorus, and potassium, one or more of them is deficient in most of 

 our cultivated soils. Of these, nitrogen is the most important, and, 

 from recent investigations, has proven to be the most elusive. Also it 

 has been shown by experiments in Germany and also in this country 

 (see New Jersey "Bulletins, Nos. 221, 224) that only from 40% to 

 about 65% of the nitrogen applied to crops is recovered or taken up 

 by the crops. This makes the subject still more interesting. 



Importance of Nitrogen. 



We pay about five times as much per pound for nitrogen, when pur- 

 chased in fertilizers, as we do for either phosphoric acid or potash. _ If 

 then the crop recovers only from 40% to 65% of the nitrogen applied,. 

 that taken up by the crop becomes very expensive. To lessen this ex- 

 pense we need to procure our nitrogen as cheaply as possible. 



Bacteria. 



It is an established fact that all legumes have the power of securing 

 free nitrogen from the air through the agency of bacteria peculiar to 

 the particular kind of legume grown. For instance, the cowpea will 

 thrive only when the bacteria peculiar to the cowpea is present ; the soy 

 bean requires the presence of bacteria adapted to that plant; crimson 

 clover will thrive only when the bacteria peculiar to that plant is 

 present; and so on throughout the entire list, with certain exceptions. 

 Those now known are: garden or English peas, and the vetches can 



