518 
Abstract Report of -Agricultural Discussions. 
sea-weed, which of course contains a considerable proportion of salt, 
is now extensively used, and the more its effects are seen, the greater 
is the demand for it. I do not think that salt should be run down as 
if it were a thing of no agricultural value ; for there are soils and 
climates where it is very beneficial when used judiciously. 
The Chairman having testified to the beneficial effects of salt in 
arresting the ravages of the turnip-fly, asked Mr. Hobbs whether he 
had known salt alone to be efficacious in destroying insects ? 
Mr. Fisher Hobbs said he had never found any active property of 
that kind in salt when applied by itself, but in combination with other 
manuring ingredients it had so operated. A more powerful agent 
than salt was required to destroy the fly ; and it should be applied 
when the plant was humid, for it would then act most beneficially 
upon the leaf. 
Mr. Dent, M.P., woufd like to know whether Mr. Lawes had made 
any experiments with salt on grass land. A notion had generally 
prevailed that the application of salt to land bearing rough or coarse 
grass had a tendency to produce a finer kind of herbage. He had always 
been in the habit of applying salt for mangold wurzel. For some 
years he grew very good crops, but he did not believe that for the last 
four years any one in Yorkshire had produced a satisfactory crop ; yet 
the crops there had, he believed, been grown vezy much in the same 
manner every year, and with the same proportion of salt. The use of 
salt had certainly, in Yorkshire, the effect of stopping the maggot, 
which was eating the leaf. 
Dr. Voelcker said, from what he had seen on a large scale in pass- 
ing through different counties of England, and from his inquiries into 
the circumstances under which salt had been used, he had come to the 
conclusion that in light and sandy soils salt was often, if not gene- 
rally, used with veiy great benefit ; while on heavy soils it was 
attended with either no advantage whatever, or decided disadvantage. 
Amongst the properties of salt there was one which belonged, he 
believed, to all very soluble saline matters, viz., that of retarding the 
growth of plants when applied in quantities of above 3 cwt. per acre. 
Salt certainly retarded the growth of plants, and for that very reason 
it was, he believed, that it was of such great utility on the lighter 
soils. It kept the plant for a longer time vegetating and in good 
growing condition, and the final result was a larger produce, especially 
in the case of mangolds. In the eastern counties the moderate use of 
salt had very materially increased the root-crop, and, as he believed, 
in virtue of its retarding the growth of the plant. In lighter soils, 
when dry weather set in, roots were very apt to dwindle away, or to 
yield only half crops ; but by applying salt in moderate quantities, 
provided the land were otherwise well manured, the life of the plant 
was prolonged, and a larger crop ultimately obtained. But the reverse 
of this was the case when salt was applied to heavy land. In some 
parts of Gloucestershire the crop was sometimes taken up before it 
was ripe, and the mangold was there less valued in consequence. The 
use of salt on stifl" clay soils, such as those referred to, would further 
retard the ripening. The use of manures like superphosphates* which 
