NITROGEN GATNKI) oi: I.osT I'li 



amount of nitrogen for the l.ind wliidi wf havr im humus 

 of calculating, but which we know is sulHciciit to lH>ii.'fii ilu- 

 succeeding crops for at least three years. r.il.lc l,XXI\'. 

 shows the removal of nitrogen per acre pci- .iiiiiiiiii mi the 

 plots growing beans and (^lover wlicre tlic root croii i-^ com- 

 pletely carted away. 



Table LXXIV. — Nitrogen removed hi/ Crops (iruwn in rotation, A;fd>ll 

 Field. Avercuje of eight Cowr.sfs, 1852-1883 RooU varfal. 



On the plot receiving mineral but no nitrogenous manure 

 the removal of nitrogen is now nearly 40 lb. per acre i»er 

 annum ; but if we exclude the clover or l)ean crop as proM'ding 

 its own nitrogen, the loss is only a little over '1'.) II ». pci- aci<' 

 per annum, some of which is undoul)tedly replaceil by iIh* 

 nitrogen drawn from the atmosphere and left in the roots and 

 stubble of the clover. With the nitrogenous manuring for tlie 

 Swedes the annual removal of nitrogen amounts to nearly «)4 lb. 

 per acre per annum, or again excluding the amount contaiinMl 

 in the clover or beans, to about 41 lb., of which the nitroumous 

 manm'c used for the Swedes provides IJo lb., reducing the net 

 loss to the soil to about G lb. of nitrogen per acre jx-r .•innuni. 

 This is easily compensated for by the amount of nitrogrn intm- 

 <luced by the clover crop, and there is every indication that the 



fertility of this plot, so far from fallin-- oil', has I n increased 



somewhaD by each completed rotation. Ilciicc wc can con- 

 clude that fairly strong land, such as wc arc dcalim: with, 



