EXPERIMENTS ON THE MIXED HERBAGE OF PERMANENT MEADOW. 359 
the whole the appearance of restricted growth from deficiency of nitrogenous supply ; 
much more so than is the case on plot 6, where the mixed mineral manures have for a 
longer period succeeded the ammonia-salts. 
So far, therefore, there is little indication that much of the nitrogen previously 
supplied in the nitrate, and not recovered in the crops grown in the years of its appli¬ 
cation, will be gathered up under the influence of the mineral manure and the more 
varied flora it induces. 
15. Equal Nitrogen, and equal Potass, in Nitrate of Soda and Sulphate of Potass, and 
in Nitrate of Potass; in each case with Superphosphate of Lime; Plots 19 and 20. 
The marked effects of nitrate of soda, and of sulphate of potass, pointed to the 
interest of determining whether nitrate of potass, or a mixture of nitrate of soda and 
sulphate of potass, containing the same amounts of nitrogen and of potass, would be 
the most effective? Accordingly, in 1872, two plots (19 and 20) were set apart foi 
experiments on the point. In each of the seven years, 1872-78 (and the experiment 
is still in progress), plot 19 has received 275 lbs. nitrate of soda, and plot 20, 327 lbs. 
nitrate of potass, both containing the same amount of nitrogen. Plot 19 has also 
received 290 lbs. sulphate of potass, containing the same amount of potass as the 
327 lbs. nitrate of potass. Each plot has also received annually 3| cwts. superphos¬ 
phate of lime. For comparison with the results so obtained there is also given, in the 
following table, the average produce over the same seven years, and also over the 
preceding 14 years, on plot 16, manured annually, during the whole period of 21 years, 
with 275 lbs. nitrate of soda, 300 lbs. sulphate of potass, 100 lbs. sulphate of soda, 
100 lbs. sulphate of magnesia, and 3| cwts. superphosphate of lime. 
