C22 STORRS AGRICULTURAL EXPERIMENT STATION. 
At the close of this article will be found a series of tabular 
statements, giving the results in detail. In all cases, the yield 
of shelled corn per acre is reported on the basis of 11 per cent. 
water, and the stover on the basis of field weights. | 
EXPERIMENTS BY M. H. DEAN. 
The field upon which these experiments were located is in the 
Housatonic Valley. The soil is alluvial, light loam, with very 
little vegetable matter, and apparently worn down by previous ~ 
cropping without manure. 
Experiments similar to the one of 1893 were conducre by the 
Station on this field in 1889 and 1890, the order of plots and the 
kinds of fertilizers being the same each year. The quantities of 
fertilizers used in 1890 were double those used in 1889, for each 
plot. The most marked results of the earlier experiments were 
the large increase in yield from the use of potash and nitrogen, 
and the apparently injurious effects of phosphoric acid. In both 
the years 1889 and 1890 plot E, with nitrate of soda and muriate 
of potash, gave a larger yield than plot G with the same fertil- 
izers and dissolved bone-black in addition. In 1890, plot Ga was 
added in place of the plaster plot (H). This plot was similar to 
Gin the amount of nitrogen and potash used, but had a very 
large amount of phosphoric acid. The yield on Ga was some- 
what greater than on G, but was less than on E, where only 
potash and nitrogen were used. 
This led to the query as to whether the soluble phosphoric — 
acid, in the form of dissolved bone-black, did not prove injurious 
to the crop. The following was offered, at that time, as a pos- 
sible means of explaining the peculiar phenomenon: 
‘‘This apparently injurious effect of soluble phosphates is most frequent on 
sandy soils, naturally deficient in nitrogen. The most plausible explanation 
seems to be that the soluble phosphoric acid, in the absence of an abundant 
supply of available nitrogen, checks the growth and hastens maturity. The 
leaves turn yellow and the crop prematurely ripens, and a smaller yield results.”’ 
In 1891 an experiment in green manuring was undertaken on 
this field for the purpose of ascertaining if the absence of an 
available supply of nitrogen might account for the lighter yields 
of corn when soluble phosphates were present in excess. 
Cow peas were sown broadcast upon the entire field about 
June 1st, 1891, at the rate of one bushel per acre. A medium 
heavy growth was produced, and the crop was plowed under and 


