36 
ELEMENTS OF AGRICULTURE, 
combine with water; and the least heat causes it to los* 
the little moisture that it might possess. 
19. Sandy lands do not easily combine with manures, 
the soluble parts of which are either carried off by rains, 
or filtrate through the sub-soil. This renders it necessary 
to put on weak manures, and renew them frequently. 
20. Sandy lands, being very friable, do not require much 
work; for we would thereby increase a porosity already 
too great, and render the roots of the plants cultivated in 
them liable to exposure. To avoid this difficulty, these 
lands are often left in pasture for several years ; sometimes 
they are rolled, after being sown, to render them more 
compact; or sheep are penned upon them. In the latter 
case, the soil is improved in two ways; by the tramping 
of the sheep, and by their droppings. Sandy lands possess 
the advantage of clayey lands, in being at all times in a 
condition to work without injury. 
21. Sandy and gravelly soils differ in value, agreeably 
to the state of the silica, and the proportion in which it is 
combined with other elements. When they are composed 
of coarse sand and pure gravel, they are of little or no 
value ; for they will yield but poor crops, even with a great 
outlay in manure. Some writers have advised these lands 
to be converted into meadow; but this can only be done 
(if then at a profit) where they can be easilv irrigated; 
for without the necessary moisture, most of the natural 
meadow-grasses would speedily perish, in seasons of 
drought. 
22. Of the cereals, rye is almost the only grain that suc¬ 
ceeds well in sandy lands ; wheat, and even barley, do nc 
thrive on them. But Indian corn, buckwheat, and root 
crops, with plenty of manure, will do very well. Crops 
ripen earlier in these soils; but their early maturilv is 
sometimes at the expense of their quality. Root crew 
grown, upon them, if not so heavy, are more nutrition 
