1908.] 



Farmyard Manure. 



167 



to some of the undigested residues which will remain for a 

 very long period in the soil before becoming available for the 

 plant. In consequence dung is a lasting manure, which 

 accumulates in the soil to build up what a farmer calls " high 

 condition," the state of affairs which prevails when the reserves 

 of manure in the soil are steadily and continuously passing 

 into the available condition in sufficient amount for the needs 

 of the crop and there is no necessity for freshly applied active 

 manure, a state of affairs which results in healthy growth 

 and good quality. But, however marked the farmers' preference 

 is for such lasting manures, the delay in realising the capital 

 they represent means a certain amount of loss, besides which 

 some of the constituents of farmyard manure are so slow 

 acting to be hardly recoverable during the lifetime of the 

 tenant. The imperfect recovery of the nitrogen from large 

 dressings of farmyard manure is illustrated in Table X, which 

 shows the nitrogen removed in the mangold crops at Rothamsted 

 when grown with farmyard manure and other sources of nitrogen. 



Table X. — Mangel Wurzel. Relation between the Nitrogen 

 Recovered in Crop and that Supplied in Manure. 



Plots. 



Manure. 



Average 

 Produce 

 per Acre 

 of 

 Roots. 



Nitrogen. 



Per Cent, 

 in 

 Fresh 

 Roots. 



Per Acre 

 per 

 Annum 



in 

 Roots. 



Supplied 

 in 



Manure 

 per Acre 



per 

 Annum; 



Recovered 

 in Roots 

 for 100 in 

 Manure. 



4 N 



4 A 



4 c 



1 0 



Tons. 



Nitrate of soda, 550 lb. ... 17*95 

 Ammonium salts, 400 lb. 15*12 

 Rape-cake, 2,000 lb. ... 20*95 

 Farmyard manure, 14 tons 17 '44 



1 



P" 164 

 o- 145 

 O" 148 

 O" 162 



Lb. 

 67 • 2 



49'3 

 69-4 



63-3 



Lb. 



86 

 86 

 98 

 200 



Per Cent. 

 7 8-i 



57'3 

 70*9 

 3i-6 



In this case 78 per cent, of the nitrogen applied as nitrate 

 of soda is recovered in the crop and 71 per cent, of that applied 

 as rape-cake, while only 32 per cent, of that which was estimated 

 to be included in the dung has come back in the crop. This low 

 figure is partly due to the fact that the dung was put on year 

 after year in considerable quantities (14 tons per acre) ; hence 

 all the wasteful processes are increased and there is also a 



