Experimental Croj)s at Rotliamstcd. 
117 
so may the development of root be tlie more encouraged under 
the inlluence of the nitrate ; and so, proportionately, will the 
plant gain greater possession of the soil, and consequently be 
able to avail itself of a wider range of both food and moisture 
within a given time. Further, from the results which have been 
recorded on the point in the foregoing pages, it would seem that 
when the nitrate is applied year after year on the same plot for 
many years in succession, the action on the soil and subsoil of its 
solution, or of that of the products of its decomposition, tends to 
increased disintegration, and to increased power of retention 
of moisture, and thus, again, to encourage a greater extension of 
root, 
Kesults relating to the Growth op Barley. 
Our next and last illustrations have reference to the growth of 
barley. This crop has been grown at Rothamsted for nineteen 
years in succession on the same land, Avithout manure, with farm- 
yard manure, and with numerous artificial mixtures each year. 
The fluctuations in the amount of produce dependent on season, 
manure, and the continued growth of the crop, being greater 
than in the case of wheat, it would occupy too much space to 
follow up the same line of illustration as that adopted in regard 
to that crop ; and it is the less necessary or desirable to do so, 
as we hope to report the whole of the results after the twentieth 
crop in succession has been harvested. 
Referring to the influence of the variation of rainfall from 
year to year, it will suffice to say here that extremely low produce 
of barley was obtained with both a great excess and a great 
deficiency of rain during the months of active vegetation. The 
bad result with excess of rain was coincident with unusually 
low, or unusually high temperatures ; and that with deficiency 
of rain with high temperatures. On the other hand, the 
highest amounts of produce were obtained with only moderate 
amounts of rain during the growing period, provided there were 
a favourable distribution of it, and a favourable adaptation of 
temperature. And whilst an excess of rain, during the growing 
months, is adverse to the favourable growth of both wheat and 
barley, a great deficiency of rain during that period is found to 
be, as would be anticipated, more adverse to the spring-sown 
barley than to the winter-sown wheat. 
In the experiments on barley, equivalent amounts of nitrogen, 
as ammonia-salts and nitrate of soda respectively, have not been 
employed in conjunction with mineral manures from the com- 
mencement ; but where they have been employed, each separately, 
without such admixture, a similar result is observed as with both 
