of a nitrogenous manure may be fairly credited to the 

 manuring. To illustrate the effects of nitrogen on ordinary 

 farm crops grown in rotation, the results obtained in experi- 

 ments carried out in the year 1886 by the Norfolk Chamber 

 of Agriculture, in conjunction with the Royal Agricultural 

 Society* may be taken as fairly representative. They are 

 as follows : 



TABLE II. 



Crop. 



Phosphates, Potash, and 

 Phosphates and Nitrogen. 



Potash. Average of Various 



Dressings. 



Corn. Straw. Corn. Straw. 



Bush. Cwt. Qrs. Lbs. Bush. Cwt. Qrs. Lbs. 



Barley after swedes . . . . 44-5 25 1 26 53'93 28 22 



Barley after wheat . . . . 34-8 18 1 17 38-59 22 2 25 



Tons. Cwt. Qrs. Lbs. Tons. Cwt. Qrs. Lbs. 

 Swedes (average of three 



farms) 15 4 1 3 18 5 2 6 



Mangels 17 5 3 20 21 12 23 



In every case, a larger crop was grown where nitrogen 

 was supplied in addition to phosphates and potash, though, 

 as might be expected, the difference was not so great in pro- 

 portion as in the Rothamsted experiments, where cropping 

 and manuring were continually the same year after year. 



In the Norfolk experiments, no plots were dressed with 

 nitrogenous manure only. An experiment carried out at 

 Pontefract under the direction of the Agricultural Depart- 

 ment of the Yorkshire College in 1895 g ave typical results 

 as to the effect of nitrogenous manuring alone on swedes 

 on ordinary farm land. Phosphates and potash gave 

 1 8 tons 2 cwt. 1 6 Ibs. of roots per acre ; with nitrogen in 

 addition, 19 tons 12 cwt. 46 Ibs. ; but nitrogen alone gave 

 only 15 tons 8 cwt. 94 Ibs. the order of the produce of 

 different manurings being the same as that with swedes at 

 Rothamsted. Here, then, we see that nitrogenous manures 

 used by themselves are not to be relied on for crops gro\vn 

 in the ordinary course of farming, any more than under the 

 conditions of experiment at Rothamsted. We shall have 

 occasion to refer later to many other instances of the same 

 thing. 



Do NITROGENOUS MANURES IMPOVERISH THE LAND ? 



Something must be said on the common idea amongst 

 farmers that nitrogenous manures are exhausting to the 

 land. Obviously, if larger crops are grown by the use of 

 nitrogenous manures, and these crops therefore remove 



* "Journal of the RDyal Agricultural Society of England," Vol. XXIII., 

 S.S., Part 1. 



