May, 1938] 



Experiments With Grass Hay 



19 



' ' A difference of one month in time of cutting, as between June 20 and 

 July 20 under the conditions here reported, means a difference of at 

 least 50 per cent in digestible protein per acre in favor of the early cut 

 hay." (This latter statement was made as a result of feeding trials in 

 the nutrition laboratory of the N. H. Agricultural Experiment Station 

 by Prof. E. G. Ritzman and his associates.) 



The same plots were harvested in this test over a period of eight 

 years. Except for 1930 they were all top-dressed alike with a nitrogen 

 carrier containing 36 pounds of elemental nitrogen per acre, and in 1937 

 phosphoric acid and potash were added to the nitrogen application. 



Average yields declined to some extent during the eight-year period 

 and certain weeds, notably devil's paint brush, secured a foothold dur- 

 ing this time. This was due to the age of the stand and continued har- 

 vesting, but weeds appeared to be somewhat more noticeable on the series 

 cut June 20 and June 30 than on the plots cut at other dates. No ap- 

 preciable difference in this respect was noticed, however, until the sixth 

 year of the test so it seems to be of little practical import as most farm- 

 ers have or should have plowed their fields by this time in the rotation. 



The difference is reflected, however, in yield data presented in Table 

 XX, where the first cuttings are grouped into two four-year periods, 

 1930-33 and 1934-37 inclusive. According to these data, the yield was 

 more nearly maintained on the June 10 plots thaij on any other series, 

 while the June 30 plots show the greatest decrease when compared 

 with the average for the first four-year period. (The percentage re- 

 ported in Column 3, Table XX, was obtained by dividing the yield for 

 the second four-year period by the yield of the first four-year period 

 for the same date.) 



Table XX. Comparison of cutting dates at Weld farm. 



Table XXI gives the average yield of dry matter and protein per acre 

 and the percentage of protein in the hay cut at different dates for the 

 entire eight-year period. From the data it appears that the dry matter 

 per acre increases from the time timothy plants begin to head (June 10) 

 until they are almost ripe (July 30). Conversely there is a fairly 

 steady reduction in the amount of protein per acre, at least in that 

 portion of the hay which is normally harvested, and a steady and con- 

 sistent decrease in percentage of protein in the dry matter. 



From the practical viewpoint these facts have much significance since 

 New Hampshire and New England are in a protein deficient region, 

 high protein feeds representing the dairyman's biggest cash expense. 



