CHAP, v.] RIPENING ACTION OF PHOSPHORIC ACID 137 



which show the results of certain determinations made 

 upon barley cut at regular intervals during the develop- 

 ment of the grain from some of the Rothamsted barley 

 plots in 1904. 



The two lower curves show the rate of the formation 

 of the grain week by week, calculated as percentages of 

 the weight of the whole plant, for the two plots which 

 receive phosphoric acid and for the corresponding plots 

 without, both series being similarly treated as regards 

 nitrogen and potash. It will be seen that the formation 

 of grain begins earlier where phosphatic fertilisers have 

 been used, and even at the end is more complete. 

 Similarly, the two upper curves show the migration of 

 the nitrogen to the grain, again calculated as percent- 

 ages of the nitrogen of the whole plant, and, as before, 

 the movement of nitrogen begins at an earlier date, and 

 is more completely carried out when there is plenty of 

 phosphoric acid. 



Table XXXIV.— Effect of Phosphoric Acid and Potash upon 

 Barley at Rothamsted. Wet and Dry Year compared. 



As might be expected, this ripening effect of phos- 

 phoric acid will be particularly seen in a wet year when 

 the crop is late to harvest. Table XXXIV. will illus- 

 trate the point : it gives the yield and other particulars 



