202 Agricultural Education and Forestry Exhibition , 1906. 
Diagram 1 showed the effect of increasing amounts of nitrogen applied as 
salts of ammonia ; the amount of grain increased with each addition of nitrogen, 
but the straw received still greater benefit. 
Diagram 2 showed a comparison between equal amounts of nitrogen applied 
as nitrate of soda or ammonia salts ; the nitrate of soda is the more effective 
manure for wheat at Eothamsted, especially as regards the straw. 
Diagram 3 illustrated the law of diminishing returns, and showed that with 
increasing amounts of manure a point is reached when the extra yield ceases 
to be profitable ; and that this point is sooner reached when the prices for the 
grain and straw are low than when they are high. 
Diagram 4 illustrated the results of applying salts of ammonia in autumn 
instead of in spring, or in alternate years instead of every year. There is 
always some loss with the autumn application, and in the second year the 
wheat receives no benefit from ammonia salts applied in the previous season. 
Diagram 5 showed that the benefit of a summer fallowing on the succeeding 
wheat crop is lost if a wet autumn and early winter follow the fallowing. 
2. Three diagrams illustrating the continuous growth of 
barley for fifty-one years, 1851-1902 : — 
Diagram 6 showed the relative effects of quantities of nitrogen applied as 
ammonium salts, nitrate of soda, or rape cake, all of which gave the same 
returns when accompanied by phosphates and potash. 
Diagram 7 showed that after farmyard manure had been applied for twenty 
years and then discontinued, a very large residue of fertility was left behind, 
which is still having an effect upon the crop, thirty-two years since the last 
application. 
Diagram 8 showed the effect of different mineral manures upon barley, and 
illustrated the great value of phosphoric acid to this crop. 
3. Experiments upon mangels at Rotliamsted, twenty- 
seven years, 1876-1902 : — 
Diagram 9 illustrated the dependence of the mangel crop upon nitrogenous 
manures, the yield increasing with each application of nitrogen. 
Diagram 10 showed that of the mineral manures phosphates have but little 
effect, but. that the crop required very large quantities of potash. 
4. Experiments on crops grown in rotation at Rotlia ru- 
sted : — 
Diagram 11 showed the effect of different manures when the land is 
thoroughly impoverished by cropping without manure. The swedes are reduced 
to a minimum, as also is the clover. The yield of wheat is, however, fairly well 
maintained ; as much as 19 '6 bushels per acre were obtained in 1903, after 
fifty-six years without manure. It also shows that with mineral manures alone 
the yield of swedes and of clover was very greatly increased ; the wheat and 
barley not at all. 
Diagram 12 illustrated the value of the clover crop in rotation as compared 
with a bare fallow. The yield of wheat is increased by 12 per cent., and the 
barley (three years after the clover) by 28 per cent. 
Diagram 13 illustrated the benefit to succeeding crops of feeding swedes 
on the land instead of carting them away. 
5. Four diagrams, illustrating tlie results of the Rotliamsted 
Experiments on the Feeding of Cattle, Sheep, and Pigs : — 
Diagrams 14 and 15 showed the amount of food (nitrogenous and non- 
nitrogenous) required per 100 lb. live-weight, and to produce 100 lb. increase 
in live-weight. 
Diagrams 16 and 17 showed the percentage composition of the whole 
carcasses of animals in a store and fat condition, and also the composition of 
the increase during fattening. 
