35 



WHEAT. 



Like all other plants of the natural order Gramineae 

 that is the cereals and grasses wheat benefits to an ex- 

 ceptional extent from the judicious application of nitro- 

 genous manures. This is not due to any special require- 

 ment of nitrogen on the part of the members of this order, 

 but probably to the comparative difficulty they have in 

 obtaining it owing perhaps to their habit of root develop- 

 ment, or in many cases to the season of the year when their 

 most active growth takes place. Both corn and straw are 

 largely increased by nitrogenous manuring. 



SULPHATE FOR CONTINUOUS WHEAT GROWING. 

 Experiments in continuous cropping and manuring are 

 important as indicating with far greater certainty than- 

 rotation experiments the characteristic results of applying^ 

 particular manures to particular crops. In the experi- 

 ments on continuous wheat growing at Rothamsted, the- 

 following results per acre per annum have been obtained,, 

 on the average of forty years, 1852 to 1891 inclusive : 



TABLE XIV. 



* Nitrate of soda = 43 Ibs. of nitrogen only, applied in last seven years. 



These figures are a good example of the usual relative 

 increase yielded under the different systems of manuring. 

 Mineral manures alone (sulphates of potash, soda, and 

 magnesia, and superphosphate of lime) gave little increase 

 compared to the unmanured plot ; and the plots receiving 

 nitrogenous manures only, though producing more than 

 that receiving minerals only, were yet far behind those 

 manured with both minerals and nitrogen. Another im- 

 portant point is that with nitrogenous manures only that 

 is, when the soil was well supplied with nitrogen, but was 

 deficient in the other constituents of plant food the 

 weight per bushel of corn was diminished. This almost 

 certainly implies that the quality and value of the corn 

 was less than on the unmanured plot. As a matter of fact, 

 the average weight per bushel on the two plots manured 

 with nitrogen only was lower than under any other system 



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