968 EXPERIMENT STATION RECORD. 



Attention is called to the fact that not all the nitrogen of the crop is assimilated 

 from the atmosphere, but that some of it, and probably in some cases most of it, is 

 taken from the supply already in the soil and therefore represents no gain in nitro- 

 gen fertilizer. This is most likely the case where crimson clover takes up most of 

 its nitrogen in the early period of growth. 



Of the nitrogen in the tops about 0.4 is in the stems, 0.3 in the leaf blades, and 

 the rest in the blossoms. After full bloom the blossom became richer in nitrogen 

 than any other part of the plant. The quantity of potash in the crop ranged from 

 63 to 185 lbs., and in an exceptional case, to 255 lbs. per acre. During the last 30 

 days before full bloom the quantity usually increases and the percentage in the tops 

 is always greater than in the roots, which contain from 4 to 27 per cent, or an aver- 

 age of about 17 per cent of the total potash in the plant. The yield of phosphoric 

 acid from the entire plant ranged from 11 to 38 lbs. per acre. The percentage of 

 phosphoric acid was rather uniform. It is estimated that during the 30 days pre- 

 ceding full bloom the crop gained in the money value of nitrogen from $0.94 to 

 $9.07 per acre, and the total money value of nitrogen in the matured crop ranged 

 from $16.72 to $22.54, and that of the 3 essential elements together, from $20.57 to 

 $32.84 per acre. 



The growth of crimson clover (Trifolium incarnatum), C. L. Penny (Dela- 

 ware Sla. Bid. 07, abridged ed., pp. 24, dgms. 2). — This bulletin is an abridged edition 

 of Bulletin 67, noted above. 



Experiments in grass culture, H. J. Wheeler and G. E. Adams (Rhode Island 

 Sta. Bui. 103, pp. 17-45, pis. 2). — Experiments were conducted to determine the most 

 economical quantities of acid phosphate, nitrate of soda, and muriate of potash to be 

 used annually on grass land where commercial fertilizers only are applied. The 

 land under experiment was seeded to barley, common red clover, timothy, and redtop 

 in 1898, and has now been in grass for 6 years. The details of earlier years of the 

 experiment have been previously noted (E. S. R., 15, p. 32). 



The first 2 years the full application of nitrogen consisted of 450 lbs. of nitrate 

 of soda and in subsequent years of 400 lbs., furnishing 71 lbs. and 63 lbs. of nitrogen 

 per acre, respectively. The nitrogen was applied with sufficient phosphoric acid and 

 potash. The results for the 6 years show that without nitrogen an average of 1.76 

 tons, with one-third the full application 2.51 tons, and with the full application 4.03 

 tons of field-cured hay was secured per acre. The best stand of timothy during the 

 6 years and the highest market grade of hay was obtained where the full ration of 

 nitrate of soda was used. Determinations of the shrinkage in barn-curing the hay 

 showed that it ranged from about 13 to 19 per cent. It was found that where the 

 full application of nitrate of soda was used a ton of field-cured hay removed from the 

 soil 13.1 lbs. of nitrogen, 32 lbs. of potash, and 6.5 lbs. of phosphoric acid. In each 

 of the 3 years in which the determination was made more nitrogen was supplied in 

 the full ration than was removed by the crop. With potash and phosphoric acid 

 alone the value of the crop per acre exceeded the cost of the fertilizers on an average 

 per year by $8.40, with one-third the full nitrogen application by $15.88, and with 

 the full application by $30.27. 



For 3 years an experiment was conducted on 2 plats to determine the best applica- 

 tion of phosphoric acid per acre. An average annual yield of 4.16 tons of barn-cured 

 hay per acre was obtained where 40 lbs. of phosphoric acid was supplied, and 4.54 

 tons of field-cured hay where 60 lbs. per acre was used. The yields per acre from 

 the entire test ranged from 3.5 to 5.01 tons of field-cured hay. The heavier applica- 

 tion of phosphoric acid proved most profitable. 



The potash test was conducted on the same plan as the experiment with phosphoric 

 acid. The annual application consisted of 150 lbs. of potash per acre on the one plat 

 and 200 lbs. on the other. The average annual yield of field-cured hay where 150 



