Brenchley . — The Development of the Grain of Barley . 915 
the nitrogen is in the plant by a much earlier date, by the sixth period 
(rather before the critical date for the plot), after which a gradual decline in 
quantity is noticed. The depletion of the straw in favour of the grain 
is strongly marked during the long ripening period in barley, for the 
migration of nitrogen into the grain continues for at least a week after 
the plant has obtained its maximum supply. This is still more evident in 
plot C, in which the grain continues to gain in nitrogen even when the total 
nitrogen in the plant is on the downgrade. 
Wilfarth, Romer, and Wimmer 1 have demonstrated a great loss in 
the amount of nitrogen present in barley during the period of ripening, 
and these authors assume that this loss is due to part of the plant food 
being returned to the soil by a downward flow of the sap. Le Clerc 
and Brezeale 2 confirm this loss of nitrogen to some extent, but interpret 
it as the result of leaching by rain and dew. In the Rothamsted experi- 
ments the barley from plot C is the only one in which this loss of nitrogen 
is evident, and even there it is very slight, being much less than in the 
investigations of Wilfarth, Romer, and Wimmer, but approximating more 
closely to the results of Le Clerc and Brezeale. 
1 Landvv. Vers. Stat., Ixiii, 1905, p. 1. 
2 Plant Food removed from Growing Plants by Rain and Dew. Year-book Depart. Agric. 
Washington, 1908. 
3 0 2 
