AGRICULTURAL RESEARCH IN NEW HAMPSHIRE 23 



J 942, "Fertilizer Needs of Dairy Farm Crops in the Connecticut Valley." 

 The objective of the present project is to determine the various levels of 

 potash in the soil and their relation to the persistence and longevity of 

 clovers in existing hay stands. This work adds continuity to previous 

 research inasmuch as clovers have persisted in all potash-treated plots re- 

 gardless of the application of other fertilizer elements. 



The field has been divided into two sections; the first contains plots 

 1 to 46 and the other contains plots 47 to 80. The former groups have 

 been plowed and reseeded with different levels of manure on certain 

 plots which \\ill also be top-dressed with varying amounts of potash. The 

 latter section, plots 47 to 80, was left in sod which was seeded in 1937 and 

 has been harvested for four consecutive years, 1938-1941. Some of these 

 plots exhibited a considerable amount of red clover particularly those 

 which had received an annual top-dressing of potash either alone or in 

 combinations with other fertilizer ingredients. In some instances treat- 

 ments have been modified on these plots to see if, by treating with potash, 

 clovers could be encouraged in the hay stands. Treatments on other 

 plots have been continued as in previous years and some of the check or 

 untreated plots were allowed to remain for contrast. These plots were 

 harvested once during the 1942 season. The average yields for the 

 various series follow: 



* Yields taken from Circular 61. 



Of these treatments, four were unchanged because the lime (L) 

 which appears in the hst of former treatments \\-as applied only once and 

 that in 1929. The yields as shown by the records indicate that those 

 plots receiving superphosphate and complete fertilizer held up very well 

 in 1942, clover still persisting in the stand. Potash alone (3) shows a gain 

 of about one-half ton of hay over the check plot average. Applying 

 potash to former check or lime treatments (2) did not stimulate yields as 

 much as did the annual application of potash, as in treatment 3. 



The most interesting changes are shown in treatments 5 and 6. In 5, 

 changing from a system of no top-dressing to one containing a complete 

 fertilizer with extra potash, the yield as shown by the four-year average. 

 2240 pounds, was increased to 4257 pounds in 1942. Potash alone in 

 treatment 2, used on similar plots, brought the yield only to 1682 pounds. 



