1909.] PUBLIC DOCUMENT — No. 31. 35 



the manure aud potash (4 cords of the former and 160 pounds 

 per acre of high-grade sulfate of potash) it was at the rate of 

 86.72 bushels of hard corn and 8,280 pounds of stover per acre. 

 This exj)eriraent has now continued for nineteen years, corn 

 and grass alternating during most of the time in periods of two 

 successive years each. The manure alone gives slightly larger 

 crops, but at a cost disproi^ortionally gTeater than that of the 

 product on the combination of manure and potash. 



V. The field used in experiments comjDaring different phos- 

 phates was planted to late cabbages during the past season. The 

 crop was a poor one on account of the prolonged drought. The 

 experimental result, however, was satisfactory, as it illustrated 

 as strikingly as in any previous year the marked dependence of 

 the cabbage upon a liberal supply of highly available phosphoric 

 acid. The average product of the three no-potash plots was at 

 the rate of only 2,573 pounds per acre, all heads, both hard 

 and soft, being included. The best results were obtained on 

 plots to which raw bone, dissolved bone black and basic slag 

 meal were applied, these being respectively at the following rates 

 per acre : — 



Pounds. 



Raw bone, 20,240 



Dissolved bone black, . . . . . . ' . 20,018 



Basic slag meal, ........ 19,120 



During the past year, therefore, we have on the best plots a 

 yield of cabbages eight times greater than was produced on the 

 no-phosphate plots. In 1908 these same no-phosphate plots gave 

 a yield of hay at the rate of about 4 tons to the acre, as com- 

 pared with a yield only 1,200 to 1,300 pounds per acre greater 

 on the jDlots to which the most soluble phosphates were applied. 

 These facts illustrate in a striking manner the remarkable dif- 

 ference in the degree of dependence of the two crops (mixed 

 grass and clover hay, and cabbages) upon the phosphoric acid 

 content of the soil. 



VI. The experiment on the nine-acre field in top-dressing 

 grass land with manure, fine ground bone and muriate of potash, 

 and wood ashes has been continued. The product this year of 

 the different materials was at the following rates per acre : — 



