612 The Lois Weedon Plan of Grorcing Wheat. 



their respective subsoils, the Rothamsted subsoil absorbed and 

 retained more ammonia than its surface soil ; and conformably 

 with the gfreater power in this respect of the subsoil, we find the 

 trenched land at Rothamsted absorbed and retained rather more 

 ammonia than the one which had not had any of its subsoil inter- 

 mixed with it. 



In fact the results of this second series of absorption experi- 

 ments confirm so entirely the bearings of the former one on all 

 essential points, that the arguments and conclusions already re- 

 corded do not require any modification or correction from this 

 additional evidence. 



The result of the comparative examination in the laboratory 

 of the Lois Weedon and the Rothamsted soils clearly brings out 

 the fact, that of the former, the heavy one at least, both contained 

 more nitrogen in some form, and had the power of absorbing 

 more ammonia under equal circumstances, than the latter ; 

 whilst the experiments in the field have shown, that a much 

 greater porosity, and consequently a gi'cater amount of surface 

 for atmospheric influences, is attained in this more highly nitro- 

 genous, and more powerfully absorbent heavy soil at Lois 

 Weedon, than, by an equal expenditure of mechanical means, 

 could be attained in the one at Rothamsted. The Lois Weedon 

 light land too, certainly contained more nitrogen than the 

 Rothamsted soil in its natural state ; and, as we have seen, 

 would in that same state, in all probability, acquire more under 

 equal climatic circumstances, and yield up more in a given time 

 to the growing crop. 



It would be taking a very narrow view of the case to suppose, 

 that no other circumstances than an increased supply of nitrogen 

 within the soil have had their share in the success of the wheat 

 crop at Lois Weedon. There is no doubt that the methods there 

 adopted are well fitted to develop to the highest degree the 

 healthy distribution of both the underground and above-ground 

 feeders of the plant. Those methods favour also the liberation, 

 the elaboration, and the distribution throughout the root-searching 

 area of the plant, of the mineral food of the crop, in a manner 

 that it would be impossible to emulate in the application of 

 direct manures. This system moreover, independently of the 

 mere amount of available nitrogen provided within the soil by 

 its means, secures also, better than any other means could do, the 

 perfect distribution of the assimilable nitrogenous, wherever 

 there is a liberal supply of the assimilable mineral food. It so 

 happens too, that it is just those soils which are known to pos- 

 sess generally the greatest absorptive and retentive powers, that 

 have generally also tlie greatest stores of most of the necessary 



