Nitrogen Recovered, and not Recovered, in Wheat & Barley. 197 



time, and barley in like manner from 1852 up to the present 

 time. In the case of each crop, one plot has received 14 tons 

 of farmyard manure per acre per annum, and another a mixed 

 mineral manure, without nitrogen, every year. The results 

 shown in Table LI. were obtained from these plots. 



TABLE LI. NITROGEN SUPPLIED IN FARMYARD MANURE, RECOVERED, 



AND NOT RECOVERED, IN THE INCREASE OF PRODUCE OF WHEAT AND 



OF BARLEY. 



Nitrogen per Acre per Annum. 



For 100 Nitrogen 

 in Farmyard 



It will be seen that the figures in the fourth column are 

 got by deducting those in the second from those in the third. 



After making allowance for certain variations in the method 

 and duration of the experiments with wheat and barley, 

 on the one hand, and with the meadow herbage on the other* 

 the general result is that, according to the estimates, a higher 

 proportion of the supplied nitrogen was annually recovered 

 over the twenty years in the autumn-manured and autumn- 

 sown (and so longer grown) wheat, than in the spring- 

 manured and spring-sown barley ; and that about the same 

 proportion was recovered in the barley as over the eight years 

 in the grass. Obviously the estimate of the nitrogen in the 

 increase is likely to be nearer the truth in the case of the two 

 cereal crops than in that of the mixed herbage, the character 

 of which, and consequently the capability of collection from 

 normal sources, is so changed by manure. Any way, neither 

 with the wheat, the barley, nor the mixed herbage, was there 



