Agricultural Research in New Hampshire 25 



Plots treated with annual applications of all three elements outyielded 

 the untreated comparable checks 1.41 tons per acre each year. Individual 

 increases for the three elements applied separately when added together 

 total 1.31 tons per acre each year. The returns for the complete applica- 

 tion amount to $2.48 for each dollar invested in fertilizers. 



Two tons of ground limestone applied in 1926 and an additional ton 

 spread in 1933 have proved to be as effective in producing alfalfa as four 

 tons applied in 1926. 



In a five-year trial with alfalfa on unmanured land nitrogen in the 

 amount of 30 pounds of elemental nitrogen per acre paid good returns. 



It was also found with one set of plots that 750 pounds of a 4-16-16 

 or even an 8-16-16 fertilizer equivalent could profitably be applied. While 

 th's amount of fertilizer may prove to be more than the average farmer 

 would risk, it does nevertheless show the possibilities that might be ob- 

 tained by liberal fertilizer use on the alfalfa crop. 



Applying all the phosphoric acid and potash prior to seeding proved 

 to be slightly superior to applying the same quantity of these materials 

 in equal annual top-dressings. This project has temporarily been dis- 

 continued. (F. S. Prince, P. T. Blood, T. G. Phillips, G. P. Percival) 



A Fertilizer Experiment with Dairy 

 Farm Crops in the Connecticut Valley 



Two circulars have been published on this experiment in past years. 

 Upon the revision of the experiment, a rotation of crops was instituted 

 on the field and the data that have accumulated on corn and hay crops 

 since 1936 have been prepared for publication. Excerpts from the con- 

 clusions that are presented in the manuscript are here submitted. 



An experiment involving a rotation of corn followed by a hay seed- 

 ing which was harvested four seasons is discussed in this circular. The 

 soil had previously exhibited a strong response to potash when applied to 

 alfalfa and clovers. 



In contrast to legumes, silage corn on these plots was much more 

 responsive to phosphorus than to potash. The largest yields of silage 

 corn were obtained from plots on which manure and superphosphate 

 w ere used together. 



In the mixed clover and timothy seeding which followed the silage 

 corn potash proved to give the greatest stimulation to yields of any single 

 substance. The response from potash was due more to the clover which 

 persisted on all treatments receiving this element than to any other factor. 

 The timothy on these plots, however, made a larger growth either because 

 of potash stimulation or secondary stimulation from its association with 

 the clover. 



Used alone as a top dressing superphosphate failed to increase yields 

 to -a significant extent. Used in conjunction with potash, however, the 

 increase in yield was more than doubled over the increase caused by 

 potash alone. 



Of the fertilizer variations tried, potash alone gave the greatest re- 

 turn on the bas : s of the money invested, but the superphosphate-potash 

 and complete fertilizer treatments gave the highest return per acre. 



From this experiment, it would seem that if red clover does not 

 persist in the hay stand the farmer has not kept his available potash at a 



