352 Report of Experiments on the Grotctk of Barley, 
— potass, and phosphoric acid, for example — are, at any rate in 
the case of the heavier soils, almost wholly retained by them 
within the range of the roots ; and they are found to be A ery 
lasting in their effects upon succeeding crops, provided there be 
a sufficient available supply of nitrogen within the soil. 
Section V. — Eesults obtained in other Fields, and under 
OTHER CONDITIONS AS TO CROPPING, MANURING, &C. 
Before attempting to give a general summary of the results of 
the experiments on the growth of barley for 20 years in succes- 
sion on the same land, or to draw any general or practical con- 
clusions from them, it will be well to call attention to some 
results obtained in other fields, and under different, and in some 
cases less artificial, conditions as to cropping, manuring, &c. By 
the aid of the comparisons thus afforded, some judgment may be 
formed as to whether any conclusions drawn from the results 
obtained under the unusual conditions of the experiments which 
have been detailed, may be trusted as a guide to the require- 
ments of the crop when grown on other land, or in the ordinary 
course of farming. 
Two sets of experiments will be noticed. In the first of these, 
barley was grown for 3 years in succession on a series of plots 
which had previously been differently manured, and grown 10 
crops of turnips in succession. In the other case, barley has been 
grown in four-course rotation, without manure, and with different 
descriptions of manure. 
1. Three Years of Barley after Ten Years of Turnips — 
Barn Field. 
The results of these experiments were considered in some 
detail in our former paper on the Growth of Barley (vol. xviii., 
Part II., 1858), and they will therefore be referred to less fully 
in this place. 
For the turnips, the area of from 7 to 8 acres was divided into 
numerous plots, differently manured ; and the object in view in 
afterwards taking 3 unmanured barley-crops from the land was to 
test the actual and comparative condition for corn-growing, in 
which the different plots had been left, and, as far as possible, to 
equalize their condition (especially so far as the nitrogen which 
had been supplied was concerned), before commencing a new 
series of turnip experiments. 
The turnips were grown in the 10 years 1843-1852 (Norfolk 
Whites 6 years, Swedes 4 years). In Table XLVllI. (p. 355) 
