116 BULLETIN OF THE BUSSEY INSTITUTION. 
No. 7.— A Record of Trials of various Fertilizers upon the Plain- 
field of the Bussey Institution. By F. H. Storer. Third 
Report. Results obtained in 1873. With a Review of the Three 
Years Course of Hxperiments. 
Tue field experiments of 1873 were of two kinds or classes. Those 
of the one class were exact repetitions of the experiments of 1871 and 
1872, described in the preceding reports ; while the other class com- 
prised trials of a number of mixed fertilizers, which were compounded 
with the view of competing with farm-yard manure. For the sake of 
convenience, the experiments with mixtures will be described first. 
The argument on which the mixtures were based was as follows : — 
It appears from the best crops obtained in 1871, that as much as 
8.5 kilogrammes of barley grain and 23 kilogrammes of barley straw, 
10 kilogrammes of beans and 11 kilogrammes of bean straw, 81 kilo- 
grammes of ruta-bagas and 47 kilogrammes of ruta-baga leaves, may 
be harvested respectively from one of the 5 X 5 metre squares of the 
experimental field. But from Wolff’s table of the average composition 
of agricultural plants, as shown by analysis (cited in Johnson’s ‘‘ How 
Crops Grow,” New York, 1868, p. 376), we know that there is ordi- 
narily taken off the land in crops of these kinds and amounts the fol- 
lowing quantities of potash, phosphoric acid, and nitrogen, namely :— 
By 8.5 kilo- By 28 kilo- Hence each square 
grammes of grammes of Total. should receive 
barley grain. barley straw. about 
Grms. Grms. Grms. Grms. . 
Potash © ay 214 255 250 K,O. 
Phosphoric acid 61 42 103 100 P,O,. 
Nitrogen. . 128 110 238 200 N. 
By 10 kilo- By 11 kilo- Hence each square 
grammes of grammes of Total. should receive 
beans. bean straw. about 
Grms. Grimms. Grms. Grms. 
Potash . . 120 209 329 330 
Phosphoric acid 80 44 124 125 
Nitrogen . 400 ~ 176 576 200* 
* Only about one third of the amount of nitrogen in the maximum crop was 
taken, from fear that a large amount might do harm. The experiments of 1871 and 
1872 had shown conclusively that in presence of carbonate or sulphate of potash 
the bean crop could obtain a good deal of nitrogen from the humus in the soil. 
