GREEN-MANURES 



549 



Table CXXV 



infltjence op the time of tubning-undee of geeen-manttees 

 on the nitrate accumuiation in the soil.^ 





Parts Per Million of Nitrates 



Crop 



In April Just 



Before the 

 Spring Plowing 



In June, Soil 



Fallowed Since 



Plowing 



Eye, fall plowed 



Eye, spring plowed 



Oats, fall plowed 



58 

 53 



61 

 36 



79 

 41 



m 



43 



57 

 67 



42 



Oats, spring plowed 



Vetch, fall plowed 



50 



45 



Vetch, spring plowed 



Average, fall plowed 



Average, spring plowed. . . . 



67 



48 

 61 



It is apparent that the decay of the green-manuring crop 

 is hastened by fall plowing, as the nitrates in every ease are 

 higher in April on land so handled. In June, however, the 

 nitrate accnmnlation has passed its highest point in the fall- 

 plowed soil, leaving the spring-plowed plats, where the decay 

 was initiated later, in the ascendancy. The table also shows 

 the advantage that a legnme has over a non-legume in causing 

 nitrate accumulation. Oats fall-plowed appear about on an 

 equality with rye. Spring plowing, since the oats are then 

 dry and dead, gives the rye a marked advantage. All of the 

 points above noted have a very practical field application. 



In turning under green-manures, the furrow slice should 

 not be thrown over flat, since the green-crop is then deposited 

 as a continuous layer between the surface soil and the sub- 

 soil. Capillary movement is thus impeded until a more or 



^ Unpublislied data. Dept. Soils, Cornell TTniversity, 



