1917.] PUBLIC DOCUMENT — No. 31. 51a 



While the yield obtained (being about 3 tons per acre of hay 

 and rowen) must be considered quite satisfactory, it will be 

 noticed that there is not a great difference in yield on the 

 different plots. This lack of variation is explained largely by 

 the fact that there was very little clover on any of the plots 

 this year. In former years, when the crop has been mixed 

 grass and clover, the noticeable difference in the yields on the 

 different plots has been due largely to the fact that the clover 

 seemed to do better on plots where high-grade and low-grade 

 sulfate of potash were used. 



Considering the whole period covered by the experiment we 

 find that high-grade sulfate of potash has proved the best 

 source of potash for legumes; that no benefit has been derived 

 from the use of feldspar, either in large or small quantities; 

 that kainit and muriate have given fully as good results as the 

 other potash salts when the crop was timothy and red top; 

 and that when potatoes have been grown the no-potash plots 

 proved less resistant to blight than the other plots. 



North Corn Acre. 

 The object and purpose of this experiment is quoted from 

 last year's report: — 



For twenty-six years there have been under comparison on this field 

 two fertilizer mixtures. In one, the percentage of potash is high and 

 that of phosphoric acid low; in the other (which represents about the 

 average analysis of the commercial corn fertilizers offered on our markets) 

 the percentage of phosphoric acid is high and that of potash low. For 

 twenty years the rotation on this field has been two years grass and two 

 years corn. The seed (a mixture of timothy, red top and clover) has 

 usually been sowti in the standing corn the latter part of July. The soil 

 has not had the benefit of a green manure crop nor an appUcation of 

 manure during the twenty-six years of the experiment. The turf and 

 corn stubble which have been plowed under have been the only source 

 of humus. 



The combination of chemicals rich in phosphoric acid was ap- 

 plied the same as in previous years, taking the average analysis 

 of corn fertilizers previous to the reduction in the percentage of 

 potash. The crop this year was corn, and the yield of crib- 

 dried corn obtained was at the rate of 45.9 bushels per acre, and 



