Moisture in Turnip-Land. 
349 
that when no water runs from drains, and the soil becomes drier, 
all the rain which falls upon such land must evaporate. Indeed it 
has been found in many parts of England that about three-fourths 
of all the rain wliich falls throughout the year is evaporated, 
and thus only one-fourth part passes through the soil to drains. 
The evaporation from the earth's surface is greatest usually in 
March and April, from the circumstance of wind and sun 
together having a greater drying power than heat alone, which 
usually obtains in June and July. During the whole of the 
spring and summer, however, evaporation takes place with great 
rapidity, and it is important that dry turnip soils should be 
worked as little as possible during that period, or the chance of 
obtaining a crop is hazarded. 
Autumn or winter dunging of stubbles has been recommended 
as tending to retain moisture in soils. We believe from experi- 
ence that it has that effect, but on light soils, through which rain 
so readily filters in winter, much of the value of the manure is 
lost, and other means should be resorted to. On clay and loamy 
soils, when clean, winter dunging is the best course to pursue in 
almost every case, taking care, however, not to cart upon the land 
when wet. 
The comparative advantages of growing turnips on the Jlat 
and on ridges, have frequently been discussed ; and as the main 
sti'ength of the argument has generally consisted in show- 
ing that the flat system of growing roots was indebted for any 
superiority it might possess to its better retention of moisture 
in the soil, I make no apology for entering into the matter here. 
I have had nearly twenty years' experience in turnip growing, 
and sometimes it has seemed more advantageous to follow the 
flat system than the ridge, and vice versa. In moist climates 
ridges, when formed, leave a kind of watercourse or channel 
between the artificial heights, which acts most conveniently for 
carrying the superfluous moisture away, and not only that, but 
the ridges are left, in the intervals of dry weather, in a proper 
state for working the land, for horse or hand hoeing, as the case 
may be. Where, as in Ireland and Scotland, 40 inches of rain 
fall in a year, with a much less average temperature than in the 
south and east of England, ridges are decidedly preferable, as 
the flat surface would usually be a puddle ; but the case is com- 
pletely reversed in the dry districts of England, where little more 
than 20 inches of rain fall annually. The summer heat is also 
greater, and of course the evaporation is far more than in Scotland 
or Ireland. 
The ridge system of growing roots in any country has the 
merit of permitting of a better and cheaper cleaning of the land 
when foul than when roots are grown on the flat. 
VOL. XVI. 2 A 
