1899.] PUBLIC DOCUMENT — No. 33. 47 



3. Tho problems suggested by the results of the year 

 must be regarded as tho most valuable product of this ex- 

 periment. These problems are not solved. Their solution 

 will throw important light upon methods to bo employed in 

 compounding and selecting fertilizers. 



2. Soil Test with Onions. Amherst. 

 This experiment occupied a field which has been employed 

 in work of this kind for nine years, the several plots hav- 

 ing been every year manured alike, as described under the 

 "Soil test with corn." Tho crops in the order of rotation 

 have been : potatoes, corn, soy beans, oats, grass and clover, 

 grass and clover, cabbages and rutabaga turnips, and pota- 

 toes. The land was ploughed in the fall of 1897, and sown 

 with winter rye as a cover crop. The rye was turned in 

 before it had made much of a spring growth, April 21. 

 Fertilizers were employed this year in double the usual 

 quantities; viz., nitrate of soda at the rate of 320 pounds; 

 dissolved bone-black, 640 pounds ; and muriate of potash, 

 320 pounds, per acre. These fertilizers are each used upon 

 one plot singly, in pairs, and upon one plot all three to- 

 gether. 



The seed was sown in the customary manner, but more 

 thickly, on May 9. Germination was prompt and perfect. 

 The development of the crop throughout the season was 

 most suggestive in problems for future solution. At the 

 start plants upon the four plots, potash alone, potash and 

 bone-black, potash and nitrate, and potash with both bone- 

 black and nitrate, were much ahead of those on the plots not 

 manured with potash. There was every indication that this 

 element would almost entirely control the crop, for there 

 was good growth wherever potash was applied, and but 

 feeble growth elsewhere. The potash plots, however, after 

 about four weeks, began to lose their superiority; and it 

 was not long ere many of the plants upon these plots be- 

 came manifestly very unthrifty, and before the end of the 

 season many of them had died. Meanwhile, the phosphoric 

 acid plots began to gain ; and the results show that this, 

 more than either the nitrogen or the potash supply, con- 



