Experiments upon Swedes. 
85 
Plots 1 and 2, I think wo may safely draw tlio following conclu- 
sions from tlu! preceding experiments: — 
1. They indicate in the most decided manner the great supe- 
riority of pliosphatic matters as manuring constituents for root- 
crops. 
2. It would indeed appear that a sufficient quantity of soluble 
ph()S])hates renders other fertilizing matters superfluous on soils 
that have a constitution similar to that of the experimental 
field. 
3. Although ammoniacal salts have had some slight effect 
when a})j)licd alone, they did not appear to exercise any specific 
action on the turnip-crop. 
4. The exj)criments leave it undecided whether it is desirable 
to add ammoniacal salts or nitrates to superphosphate. At the 
same time they appear to favour the view that on clay soils 
nitrogenized matters do not increase the efficacy of soluble phos- 
phate in a turnip-manure, and to confirm my previous observa- 
tions extending over a number of years. 
5. In this series of experiments nitrate of soda had a decidedly 
beneficial effect on the turnips. 
In 18G0 precisely the same fertilizing matters were used on 
another field of our farm, and the experiments made in every 
respect in the same manner as in 1859. An unfavourable season, 
the turnip-fly, and other casualties, unfortunately spoiled my 
experiments. I am glad, therefore, that in place of experiments 
made by myself, I am in a position to communicate a series of 
experiments which I induced the late Mr. Campbell, of Craigie 
House, Ayr, to institute in 1860. Mr. J. Russell, steward to the 
late Mr. Campbell, kindly favoured me with the following 
tabular statement, showing the quantity and kind of manure 
employed per acre, its cost, and the produce in clean roots, 
topped and tailed. (See p. 86.) 
The experimental piece of ground, I am informed, appears to 
be of equal quality. The soil is considered a rich, light, sandy 
loam. Each plot was composed of 3 drills, and occupied 2 poles 
imperial measure. Distance from drill to drill 28 inches. The 
seed, Skirving's Improved Purple-top Swede, Avas sown on the 
18th of May, and the roots taken up on the 22nd of November. 
The roots grown on the central drill of each plot were carefully 
freed from dirt, topped and tailed, and weighed. The roots on 
Plots 1, 2, 3, 11, I am informed, were soon left behind. On 
Plots 1 arid 11, as will be seen, no manure was applied ; and on 
Plots 2 and 3 sulphate of ammonia only. The produce on one 
of the two unmanured portions of the land amounted to 1 ton 
more than on the other. 
