FARM EXPERIMENTS. 

 ECONOMICAL USE OF COSTLY NITKOaENOtTS MANURES. 



455 



Eugiisb eAperiuieutalists have found that in general not one-half of 

 tliQ nitrogen of such manures as guano, animonia salts, and nitrate of 

 soda, is recovered in the increase of the crop to which they are applied. 

 As to the residue, a portion may remain comparatively inactive in the 

 soil, and a considerable portion may, under conditions favorable to drain- 

 age, be carried away and lost. AVith a view to these points, experi- 

 ments were commenced at Eothamsted, England, in 1871, to determine 

 whether any economical advantage can be gained by applying such 

 manures in comparatively small quantities near the seed, Instead of 

 larger amounts broadcast and harrowed in. In the following tabulated 

 experiment with wheat, the plots measured one-quarter of an acre each, 

 and the amount of seed in each case was one bushel per acre. The 

 fertilizers in this and the barley experiment were intimately mixed with 

 ashes of burned clay before application. The 14G pounds sulphate of 

 ammonia applied on plot 2 contained nitrogen equal to that contained 

 in 15 bushels of wheat, with straw in proportion, and the imperfect re- 

 covery of the nitrogen is indicated by the fact that the yield on this plot 

 was only 7f bushels per acre in excess of that of the unmanured plot. 

 That the soil cannot be expected to return any large additional percent- 

 age of the nitrogen in seasons subsequent to that of the application has 

 been already shown by experiments at Eothamsted. In his report for 

 1861, Mr. Lawes says that the unexhausted residue of nitrogen supplied 

 in ammonia salts was but very partially and very slowly recovered in 

 increase of crop in succeeding years, even with liberal applications of 

 such mineral manures as were very effective when used in conjunction 

 with newly-applied ammonia salts. 



The subjoined is a tabulation of experiments on barley. The plots 

 were one-half of an acre each ; amount of seed, 3 bushels per acre, ex- 

 cept on plot 5, which received 1^- bushels of seed per acre. 



