EXPERIMENTS WITH NITROGEN FERTILIZERS 



N — Nitrogen. P — Phosphoric acid. K — Potash. 



1883. Grass-land plowed and planted without fertilizer of any kind. 



1SS9. All plots fertilized with phosphoric acid and potash. 



Plots 1, 2, 3, 5, 6, 8, and 10 received nitrogen; Plots 4, 7, and 9 did not receive it. 



Plot received farm manure. 



added to nitrogen on Plot 3 did not improve the yield in the least. Nitrogen 

 added to potash on Plot 10 increased the yield a little when compared with the 

 previous year. 



In his report for 1887, Dr. Goessmann said: 



The beneficial influence of a potash supply on the yield of fodder, upon our experimental plats, 

 is in every instance unmistakable. 



The continuation of the experiment in a similar manner in 1888 brought 

 about a change. The continuous use of potash alone brought about a marked 

 deterioration in yield on Plot 9. Nitrogen was withheld on Plots 1 and 5, with 

 the result that potash alone did not maintain the yields obtained on these plots 

 the previous year. The withholding of phosphoric acid on Plot 7 produced a 

 similar result. 



Dr. Goessmann's report in 1888 contained the following statement: 



A manuring for three successive years with potash alone has sufficed in our case to terminate 

 its beneficial effect on the natural productiveness of the soil, as far as the corn crop is concerned. 

 More complete manures are required to restore a desirable degree of fertility of the soil. 



The application of nitrogen to Plots 2 and 8 resulted in a positive increase 

 over the preceding year; while the substitution of phosphoric acid for nitrogen 

 on Plot 10 did not maintain the yield of the previous year. 



The fertilizer plan was changed in 1889 with the object of studying the 

 influence of different kinds of nitrogen compounds as fertilizers when the soil 

 was supplied with ample quantities of available phosphoric acid and potash in 

 standard materials. 



Corn was again the crop and was handled as in the preceding years. Three 

 of the plots, (4, 7, and 9) did not receive any nitrogen and had not received any 



