12 New HAMPSHIRE EXPERIMENT STATION [Bulletin 271 



these were top-dressed annually with 100 pounds of nitrate of soda per 

 acre, while the remainder have been left untreated. 



In the spring of 1926 nitrate of soda at the rate of 100 pounds per 

 acre and 16 per cent, superphosphate at the rate of 250 pounds per 

 acre were applied as top-dressings to certain specified plots. This has 

 been continued annually during the period studied. 



An explanation of the treatments used in this experiment follows: 



Unplowed: Ch — Untreated. Td — Top-dressed annually with 100 

 pounds nitrate of soda per acre. 



Plowed and reseeded : No treatment — No manure or fertilizer. M — 

 10 tons manure applied in 1925. MP — 10 tons manure applied in 1925 

 plus 250 pounds 16 per cent, superphosphate annually. MNP — 10 

 tons manure applied in 1925 plus 250 pounds 16 per cent, superphos- 

 phate and 100 pounds nitrate of soda*, annually. 



P — 250 pounds 16 per cent, superphosphate annually. N — 100 

 pounds nitrate of soda annually. NP — 100 pounds nitrate of soda and 

 250 pounds 16 per cent, superphosphate annually. No Lime — Two tiers 

 of plots left unlimed, but treated as outlined above. 2 T. Lime — Two 

 tons of ground limestone per Acre applied on two tiers of plots in 1925 

 as cross treatment. 4 T. Lime — Four tons of ground limestone per 

 Acre applied on two tiers of plots in 1925 as cross treatment. 



The autumn of 1925 was very dry. The seeding made September 8 

 of that year was successful only on those plots which had been treated 

 with manure. The plots were top-dressed in the spring of 1926 ac- 

 cording to the plan of the experiment, but no harvest was obtained 

 from those that had been plowed and reseeded without manure. 



In August 1926 the unmanured plots were disked and seeded again. 

 On the plots which were to receive nitrogen, nitrate of soda was ap- 

 plied September 2 at the rate of 100 pounds per acre. The grass on 

 these plots started off better than on those that were untreated. The 

 plots that had an application of superphosphate the preceding spring, 

 also made a better start. 



In the spring of 1927, it appeared that a fairly good stand of grass 

 was present on all the newly seeded plots. Top-dressing with nitrate 

 and superphosphate was again done in April 1927 on all plots receiving 

 these materials, except the ones to which nitrate of soda had been ap- 

 plied in September 1926. Since 1927, top-dressing has been practiced 

 annually about April 15 in this experiment. 



One harvest has been made each year on all these plots from 1927 to 

 1931, inclusive. The hay was cut about the last week of June, cured 

 in the field, and weighed there, an effort always being made to have the 

 hay from the plots uniformly dry. 



In Table VI the total yield for the five-year period from the un- 

 plowed plots is reported, together with the probable error, and the dif- 

 ference between the two series with its probable error. 



*Nitrate of soda was used in this experiment largely because it seemed 

 to be the most common nitrogen carrier at the time the experiment was 

 started. There appears to be no reason why calcium nitrate, sulphate of 

 ammonia, cyanamid or other nitrogen carrier could not be used just as well 

 in actual farming. 



