22 University of New Hampshire [Sta. Bui. 330 



applied just before the time of seeding. The annual units consisted 

 of 300 pounds of 20 per cent superphosphate and 100 pounds of 60 

 per cent muriate of potash. 



In contrast to the adverse 1939 hay season, 1940 was one of the 

 most favorable alfalfa years since 1925. Yield variations on the dif- 

 ferent types of fertilized plots tended to level off, perhaps because of 

 the ideal weather and because in another year all the plots will have 

 had exactly the same amounts of plant food over the three-year pe- 

 riod. While it is still early to draw conclusions from the experiment, 

 the combined data for the two years indicate that it is better to apply 

 heavy applications of plant food at seeding time rather than spread- 

 ing smaller applications annually. By the end of 1941, when all the 

 plots will have received the same amount of fertilizer, more definite 

 conclusions will be possible. 



The plots on the Ireland farm, Greenland, were seeded to pure 

 alfalfa in 1935, each plot receiving an annual top-dressing in accord- 

 ance with the fertilizing plan of the experiment. During the five- 

 year period grass has been replacing the alfalfa at an increasing rate, 

 until in 1940 the first cutting was probably one-half grass. It is sig- 

 nificant that the plots most heavily treated with fertilizers had more 

 alfalfa and less grass than the lightly treated plots. 



A combination of the five-year data shows that yields were in- 

 creased by additional increments of fertilizer up to the maximum 

 amount of 1500 pounds of 4-16-16 fertilizer per acre. However, the 

 increases were not sufficiently great to warrant the application of so 

 large an amount of fertilizer each year. The data further show that 

 nitrogen is necessary for good hay yields. An average increase of 

 904 pounds of hay per acre was obtained from plots treated with 

 750 pounds of 4-16-16 fertilizer per acre, as compared with the same 

 quantity of 0-16-16 fertilizer. However, yields were increased only 

 262 pounds by increasing the nitrogen content from 750 pounds of 

 4-16-16 fertilizer to 750 pounds of 8-16-16 fertilizer. 



Comparisons for phosphoric acid and potash show that the dif- 

 ference between 375 pounds of an 8-16-16 and 750 pounds of a 4-16-16 

 fertilizer (equal amounts of nitrogen and double amounts of phos- 

 phoric acid and potash) resulted in an average increase of 1134 

 pounds of hay, the additional hay being worth (at current prices) 

 about twice the additional cost of the fertilizer. However, increasing 

 the fertilizer application from 750 pounds of an 8-16-16 combination 

 to a 1500 pound application of 4-16-16 fertilizer (equal nitrogen) re- 

 sulted in an increase in hay worth only about one-third the cost of 

 the additional fertilizer. 



(Purnell Fund) 



Potatoes in a Dairy Farm Rotation (F. S. Prince, P. T. Blood, T. G. 

 Phillips, G. P. Percival, P. N. Scripture) 



This experiment, conducted at Colebrook, New Hampshire, is 

 laid out to test different plant food levels, different fertilizer ratios, 

 and different methods of fertilizer application, as well as different ro- 

 tation systems. Although the work has been carried on for 12 years, 



