34 



bulletin no. 5, may, 1889. 



Grasses and clovers : effect of ripeness on yield and com- 

 position, Thomas F. Hunt, S. B. (pp. 141-164). 



Uxperimeiit Wo. 50. — " The investigations reported in this bulletin 

 were undertaken to ascertain the efltect of cutting certain grasses and 

 clovers at diiierent periods of growth upon the yield of hay and its com- 

 position. The results obtained by several others who have made inves- 

 tigations on the same lines are also given, and the whole is believed to 

 be a fairly comprehensive summary of the data so far accumulated upon 

 this subject in this country." 



This article contains explanations of technical terms used in state- 

 ments of chemical analyses of grasses and clovers, including the terms 

 co-efficient of digestion aud nutritive ratio. 



" Four grasses (timothy, Kentucky blue-grass, orchard grass, and 

 meadow fescue) and two clovers (medium red and mammoth red) were 

 used in the investigation. Incidentally there was some comparison of 

 the varieties." 



A record of the observations made during the season is summarized 

 in five tables, and there is also a discussion of the composition aud 

 yields of green crop and hay at the different times of cutting. 



YIELD OF GREEX CROP AND OF CURED HAY. 



The yield per acre of green substance varied in the grasses from 3^ to 4f tons, and 

 in the clovers from 4| to 7f tons. The grasses lost while curing from If to 2f tons. 



LOSS OF WATER IN CURING. 



With an ordinary yield the loss of water while curing in the field may he from 2 to 

 5 tons per acre. The loss is larger in the clovers than in the grasses. The loss in 

 weight by drying after storing may be from 200 to 400 pounds per ton. 



CHEMICAL COMPOSITION OF PRODUCTS. 



An analysis of the results embodied in the tables given shows that while there are 

 marked exceptions, there is, in general, a decrease in the per cent of water, crude ash, 

 crude fat, aud crude protein, and an increase in the per cent of crude fiber, aud nitro- 

 gen-free extract as the plant matures during that period within which it is at all 

 practicable to harvest the crop for hay. The increase of the non-nitrogenous over the 

 nitrogenous portions has such few exceptions that they may be attributed to acciden- 

 tal variations of sampling. The decrease in the per cent of fat is quite general, but 

 there are marked exceptions. The increase in the per cent of nitrogen-free extract 

 is fairly general. The decrease of the crude protein and the increase of the crude 

 fiber is more rapid in the clovers than in the grasses. 



YIELD OF ACTUAL NUTRIENTS 



The increase of yield of the grasses from the period of fall bloom until seeds are 

 formed is appreciable. There is an increase of all the food nutrients, but the in- 

 crease is most marked in the crude fiber and nitrogen-free extract. * « * With 

 the clovers there was a decrease of yield after the period of full bloom (when about 

 one-half the heads are in full bloom). There was a decrease in all the nutrients, 



