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indirectly as a manure and serves merely as a whip to make the dormant matter active, thus placing 
nutritive matter at the disposal of the plant. Where there is no dormant matter in the soil there 
can be no beneficial action. The effect is most marked on fertile soils, in moist, warm weather on 
as there is then sufficient water to dissolve the gypsum. One part of gypsum requires 400 parts of 
water to dissolve it, clearly there can be little or no action in dry ground. Mayer commenced experi- 
ments with it in the Palatinate as early as 1765. Since his time numerous experiments have been 
made to determine its action, but these may be passed over. 
At times, an application of wood-ashes gives good results. Schwerz relates that the village of Kriegs- 
feld in the Palatinate, which had been devastated in the war and almost abandoned by its inhabitants, 
was restored to prosperity through an excellent crop of clover, produced by means of an application of 
the ashes left from burning the village. Chili sallpetre has very rarely been successfully used as a 
lop-dressing. Sulphate ammonia also rarely gives remunerative returns. In fact red clover seldom 
responds to any application of nitrogenous manure; it obtains the large amount of nitrogen il requires 
from other sources than those available to the grasses, probably from the subsoil, possibly from the air. 
At the end of autumn a covering of undecomposed farmyard manure prevents the uprooting of 
the plants by alternate freezing and thawing, 
This clover ought not to be cultivated on irrigated land. Meadows intended for irrigation usually 
receive no water for the first two years, then of course red clover can be grown, but after irrigation 
the land is unsuitable. 
Growth, yield, nutritive value. The first leaf produced by red clover is not ternate 
like the succeeding leaves, but simple and rounded. At first the tap-root penetrates the 
soil with comparative rapidity while the parts above ground grow much more slowly. In 
the axils of the radical leaves buds soon make their appearance. ‘The lowest grow out 
and become secondary branches; these in turn may again branch. If sown in spring with 
a cereal, by midsummer the branches in the air and the roots in the ground are almost 
equally developed. 
The tap-root penetrates deep into the ground and produces numerous lateral roots 
which again branch abundantly. These lateral roots penetrate the ground in all directions 
and extract mineral matter and water from it. Peculiar wartlike growths containing 
albumin and bacteria develope on the rootlets; the physiological meaning of these growths 
is not year clear. Similar warts occur on must leguminous plants. After a time, the roots 
begin to shorten and the basal parts of the plant and radical leaves are pulled downward 
into the ground. This change protects the lower buds from the scythe, gives the plant 
a firmer hold of the ground, and prevents uprooting during winter. Similar root- 
contraction is very conspicuous in carrots. In summer the carrot-top is above ground, in 
autumn below. The experiments of Hugo de Vries*) shew that a tap-root of red-clover, 
9 im. thick, became 10°/o shorter in six weeks, by root-contraction. After cutting, the 
whole stem dies down, except the short, bud-bearing internodes at the base; these buds 
soon develope and become new branches. When clover is cut for seed, the whole stem 
usually dies and becomes rotten and hollow. For this reason there is little produce after 
a seed-crop has been taken. 
*) H. de Vries, Wachsthumsgeschichte des rothen Klees. Landwirthschaftliche Jahrbiicher von Nathusius & Thiel. 
Bd, VI. Berlin, 1877. 
Growth. 
i 
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