178 BOARD OF AGRICULTURE. [Pub. Doc. 



merchantable size, to 382.3 bushels in 1902, of which less 

 than 10 per cent were under merchantable size ; leaving 350 

 bushels of large or merchantable tubers, as compared with 

 65.8 bushels in 1893. 



The complete data concerning this experiment have not 

 yet been prepared for publication ; but what has been given 

 above is enough to show that, whatever the faults in the 

 treatment of the land may have been at the outset, the 

 lessons that have been learned from the earlier failures and 

 from the recognition of the acidity of the soil and the need 

 of more nitrate of soda and nmriate of potash for the grass 

 crop are now bearing magnificent fruit, indicating that the 

 scheme of manuring, as now practised, though perhaps still 

 imperfect, is calculated to yield large profits. 



Special Experiments in Top-dressing Grass Land. 



The experiments in this line which are now in progress 

 are designed to cover the following points, viz. : — 



(1) To ascertain the minimum amount of nitrate of soda 

 which, in the presence of sufficient of the other essential 

 elements, will insure a crop of api)roximately 4 tons of hay 

 per acre annually for a series of years. 



(2) To ascertain the minimum amount of nmriate of 

 potash which, on a granitic soil, will insure a crop of 4 tons 

 of hay annuall}^ for several years, provided an abundance of 

 all the other necessary manures is furnished. 



(3) To ascertain the minimum amount of acid phosphate 

 necessary, under the conditions named in (1) and (2), to 

 secure crops of similar size. 



(4) To compare the grass crops produced under the Clark 

 S3^stem of surface preparation with those obtained by the 

 customary means. This involves using like amounts of lime 

 and other chemicals in each instance. 



(5) It is hoped the coming season to make comparisons 

 of the relative etfectivenoss of like amounts of phosphoric 

 acid, in one instance in acid phosphate, and in the other in 

 basic slag meal, in order to ascertain which will give the best 

 results in top-dressing grass lands, when the othi'r conditions 

 are identical. Only the first of these exi)eriments has as 



