March, 1938] Agricultural Research in N. H, 19 



Soil Fertility Studies 



Soil fertility experiments carried on over a period of years include: 

 an experiment with hay on neglected hay lands, an experiment with 

 legumes on neglected hay lands, an experiment with potatoes in a three- 

 year rotation, a fertilizer experiment with legumes in the Connecticut 

 Valley and experiments with topdressing old pastures. The agronomic 

 work in the studies is conducted by F. S. Prince and P. T. Blood ; the 

 chemical phases by T. G. Phillips and G. P. Percival. 



Hay on Neglected Hay Lands 



Significant differences for the treatment are apparent over a three- 

 year period. As compared with no fertilizer, nitrogen at 200 lbs. per 

 acre gave an average increase of 1,462 lbs. per acre of cured hay ; 200 

 lbs. 16 per cent, superphosphate and 60 lbs. KCl gave 728 lbs. increase 

 and the nitrogen-phosphorus-potash plot yielded 2,159 lbs. increase. 

 The data indicate that nitrogen gives the greatest stimulation to yields 

 but that phosphorus and potash, either one or both, are likewise limit- 

 ing factors to the production of grass hay on this land. 



The data from this experimental work will be included in a forth- 

 coming Experiment Station publication, ' ' Experiments with Timothy. ' ' 



Legumes on Neglected Hay Lands 



The old Whenal alfalfa plots were so reduced in stand in 1936 that it 

 was decided to plow the land, cultivate it for one season and then seed 

 back to alfalfa. Accordingly, sweet corn was grown there in 1937. 

 Fertilizer was applied to all plots uniformly at the rate of 300 pounds 

 of 8-16-16 per acre so as not to change the variables for the alfalfa that 

 is to follow. No yield records on the sweet corn were taken. Alfalfa 

 will again be seeded on the land in 1938. 



Alfalfa is being grown on the Ireland farm as a sub-project in the 

 legume experiment. In this test no manure was used. Moderate to 

 heavy applications of fertilizer are annually applied to determine the 

 nutrient levels at which alfalfa does best under those conditions. A 

 test is included in which lime was applied at rates of from to 8 tons 

 per acre. These plots have been uniformly fertilized with 300 pounds 

 of 10-20-20 fertilizer or its equivalent. A two-year summary of both 

 cuttings showed significant decreases for the no-lime and one-ton series 

 as regards lime applications. The fertilizer plots indicate that it is 

 doubtful if an application of more than 30 pounds of nitrogen or more 

 than 120 pounds each of phosphoric acid and potash are justifiable 

 under actual farm conditions. The response for nitrogen in this field 

 is rather striking. Thirty pounds of elemental nitrogen gave an in- 

 crease of 1,028 lbs. hay in the first cutting. On the other hand, the 

 doubling of nitrogen did not result in a marked increase in yield in 

 either cutting. 



A Dairy Farm Rotation on Worn-out Hay Lands 



In this fertilizer ratio experiment on the potato crop at the Lane 

 Farm in Pittsfield, the potatoes are grown in a rotation of potatoes, 

 oats, and clover. All of the fertilizer is applied to the potatoes. The 



