66 



HORTICULTURE 



LECT. IV 



ing ample supplies of nitrogen, which originally comes 

 from the air, so that the only manures required by 

 such crops are potash and phosphoric acid as contained 

 in kainit and bone meal, or Thomas's phosphate 

 powder, nitrate of soda having little effect on them. 



FIG. 14.-*THE SMALL EFFECT OF NITROGEN ON BEANS. 



1. Receiving phosphoric acid and potash, no nitrogen. 2. Small increase 

 only through adding nitrate of soda. (Wagner.) 



Liquid Manure. It is hardly possible to deal 

 fully with manures in a single lecture, but liquid 

 manure must not be passed without some notice, how- 

 ever brief. For the villa and cottage garden, house- 

 hold sewage should always be turned to account for 

 growing crops in spring and summer, and for fruit 

 trees and bushes in autumn and winter. If only the 

 soil drainage is sound it may be poured over the sur- 

 face with certainty that good is being done. Waste 



