34 



chemical manure used in the other methods gave the largest yield and 

 was profitable in all cases." 



Effect of the different forms of potash salts. — The jields with complete 

 fertilizers, containing potash in the form of sulphate, muriate, or kainit, 

 as tabnhited, show that in each case the muriate gave a slightly 

 increased yield (from 10 to 19 bushels per acre) over the sulphate. '-The 

 kainit was the least effective and in a few cases proved an injury." 



Effects of nitrate of soda. — Nitrate of soda, applied all at time of 

 planting or part at time of jilanting and the rest later, seems to have 

 been practically without elTect. "The reason for its failure to aid in 

 the production of the crop is nol clear, since the general experience of 

 both experimenters and practical fanners is that uiuforndy good results 

 have followed its use upon ]>otatoes." 



Chemical composition of the crop. — Analyses with reference to both 

 food and fertilizing ingi^nlieuts are given for samples of potatoes from 

 each plat in each of the three separate trials. 



Tlie results from all the experiiitents ajjree very closely with each other, though a 

 very niarkeil (lilVereiice ia noticed in the clVect of ihe ditVereiit f\>riii8 of potji.sh. It 

 has already heeu shown that iiiaiiiires, <»roiipi'd either aceonliii-j to the form of potash 

 or as a whole, did unfavorahly inlluenco the ]M'rcentaf;e of dry inatt«'r in the potato. 

 Of the three forms of jiotash used, the sulphate wiis the least mifavorahle, since it 

 reduced the dry matter in the average of all the experiments hut O.OH pound in 100 

 poun<ls of potatoes or '^.l percent; and the kainit was the most unfavorahle, and 

 on the same hasis reduced the dry matter hy 2..'"yj pounds or 11. S per cent; the eftect 

 of the muriate corresponded to tlie average general eftect. It is also shown that the 

 starch was atfected hy the different kinds of potash in the same relative jiroporlion 

 as the dry matter. 



The teachings of these experiments do, therefore, .accord with the oi)inions now 

 generally held, and liased upon previous experiments, namely, that potash does 

 intluence the composition of pot.atoes, and that of the dilferent commercial forms the 

 sn!|>hate is the most valnahle. 



The author states further, that in general, while the potatoes on the 

 plats receiving sulphate of potash were not as large, they were of more 

 uniform size and of smoother skin than those on the plats fertilized with 

 either muriate of potash, kainit, or baniyaid manure. When cooked, 

 the potatoes from the sulphate plats were believe«i to be of superior 

 quality. 



"As in the composition of food compounds, the variations in the 

 amounts of plant-food elements contained were not marked in the sam- 

 ples frojn different ])lats in each experiment." The amount of fertili- 

 zing ingredients removed by the crop on ea(!h farm and the amounts 

 left in the soil from the various ap[»lications, are calculated. 



The chief points brought out by the experiments of this year are sum- 

 marized as follows : 



(1) The best results were secured when chemical manures were used in connectioQ 

 with barnyard m.annre. 



(■J) Kainit was less effective than eitiier muriate or sulphate of pot.osh ; and sul- 

 jdiate of potash did not produce larger yields than muri.ito. 



(3) Nitrate of soda did not jirove a valuable fertilizer for potatoes. 



