June, 1940] AGRICULTURAL RESEARCH IN N. H. 19 



Agronomy 

 Legumes on Neglected Haylands 



This is the first year the Whenal alfalfa plot at Greenland has been 

 harvested under the present fertilizing scheme in which annual fer- 

 tilization is being compared with three times the annual amount ap- 

 plied just before the time of seeding. Units consist of 300 lbs. 20% 

 superphosphate and 100 lbs. 60% muriate of potash. 



The weather during the growing season was very dry all over 

 New Hampshire, especially after the first alfalfa harvest, and because 

 of this only one harvest was taken. While it would be unwdse as 

 yet to draw any conclusions, two things do stand out. One is that 

 potash causes greater stimulation to alfalfa than an equal amount of 

 phosphoric acid. This is in line with data previously obtained. The 

 other significant point is that thus far heavy initial applications of 

 both materials have caused higher yields than those in which the 

 amount of one or both materials was reduced to the amount used in 

 the annual application. Apparently the need of alfalfa for both 

 phosphoric acid and potash is greater than that which is supplied by 

 the annual a]iplication in the amount used. 



Alfalfa plots on the Ireland farm in Greenland were harvested once 

 in 1939 after having been top-dressed in the spring in accordance 

 A\ith the plan of the exi^eriment. Because much grass has crept in- 

 to the alfalfa stand on this field, it is quite possible that the effects of 

 nitrogen are exag'gerated and the stimulation from phosphoric acid 

 and potash is somewhat minimized. The experiment would appear to 

 indicate, if costs are considered, that the maximum top-dressing that 

 can be used with any profit ^vill approximate 300 pounds of 10-20-20 

 and 300 pounds of 0-20-20 fertilizer per acre annually. 



The effect of different rates of liming has also been studied. Plots 

 were sampled as usual in the fall of 1938 at two-inch levels down to 

 eight inches and analyses made for pH values. 



Oats were grown as a nurse crop this summer and were sampled 

 for analytical work. Because of the dry summer, the seeding of 

 clover failed and was replanted in September. This will be sampled 

 next summer. The phosphorus content of the first cutting of alfalfa 

 in 1935 showed an increase with increasing; rates of liming-, beingf 

 C.539 per cent for no lime and 0./77 per cent for the 8 ton application 

 on the moisture-free basis. 



The results on the soy-beans on an air-dry basis showed that both 

 nroteins and CaO content increased with larger applications of 

 lime. Protein increased from 12.52 to 16.43 per cent and the CaO 

 from 1.33 per cent to 2.66 per cent. 



Potatoes in a Three-Year Rotation 



The experiment at the Jackson farm in Colebrook has concerned 

 itself with a three-year rotation of potatoes, oats and hav in which 

 all the fertilizer is applied to the potato crop. The oats and hav 

 merely get any excess plant food not used by the potatoes. The 

 second crop of ha}^ is always turned under for the potatoes that are 

 to follow. Data over a period of six years show that phosphoric 



