No. 4.] CATCH-CROPS. 321 



dant. To secure the development of a sufficient number of 

 them it is just as unnecessary to supply more seed as it is 

 to scatter seed of " pusley " in the garden to secure a crop 

 of that weed. It is only when a legume is new in a given 

 locality that it becomes necessary to consider the question 

 of supplying seed of its appropriate bacteria; for while some 

 of the bacteria .seed may be present, adhering to the seed of 

 the new crop in the form of dust, the quantity will be insuffi- 

 cient for the best results the first few years. 



To supply this deficiency the farmer of to-day may easily 

 purchase nUragin^ often spoken of as a germ fertilizer; or 

 he may secure soil from the locality where the new crop is 

 known to nourish. Nitragin is not expensive, and if used 

 according to directions accompanying it, it has often been 

 found beneficial. The quantity of earth needed is not large, 

 and if scattered and mixed with the soil, as fertilizer would 

 be, it will usually produce the desired effect. 



In one other important particular green-manuring has a 

 relation to the supply of nitrogen in the soil. This element 

 is rapidly converted into soluble forms during the summer, 

 and the soil has not the ability to retain these soluble com- 

 pounds. If the rainfall is heavy and water leaches through 

 the soil it will take these soluble nitrogen compounds with 

 it. This loss can be prevented by keeping the soil filled with 

 feeding rootlets of growing plants. The myriad hungry 

 rootlets will take up the soluble nitrogen and it becomes a 

 part of the plant. It is locked up, so to speak, in the vege- 

 table tissues, and will remain so locked up until these tissues 

 decay. 



As has been pointed out, the season when this loss is most 

 likely to take place is in the late autumn ; hence, to prevent 

 this loss, or for nitrogen conservation, those crops are most 

 valuable which are not affected by the autumn frosts and 

 which will continue to grow as late as possible. Measures 

 to insure nitrogen conservation are self-evidently most im- 

 portant upon the richer soils, which are light and porous in 

 character and which have open subsoils. 



Green-manuring cannot increase the store of either phos- 

 phoric acid, potash or lime, but it can be made to increase 

 the solubility and therefore the availability of these soil con- 



