In some places the corn is beaten out by machines[593] upon the threshing-floor, in others by the feet of mares, and in others with flails. The later wheat is cut, the more prolific[594] it is; but if it is got in early, the grain is finer and stronger. The best rule is to cut it before the grain hardens, and just as it is changing colour:[595] though the oracles on husbandry say that it is better to begin the harvest two days too soon than two days too late. Winter and other wheat must be treated exactly the same way both on the threshing-floor and in the granary. Spelt, as it is difficult to be threshed, should be stored with the chaff on, being only disengaged of the straw and the beard.
Many countries make use of chaff[596] for hay; the smoother and thinner it is, and the more nearly resembling dust, the better; hence it is that the chaff[597] of millet is considered the best, that of barley being the next best, and that of wheat the worst of all, except for beasts that are hard worked. In stony places they break the haulms, when dry, with staves, for the cattle to lie upon: if there is a deficiency of chaff, the straw as well is ground for food. The following is the method employed in preparing it: it is cut early and sprinkled with bay salt,[598] after which it is dried and rolled up in trusses, and given to the oxen as wanted, instead of hay. Some persons set fire to the stubble in the fields, a plan that has been greatly extolled by Virgil:[599] the chief merit of it is that the seed of the weeds is effectually destroyed. The diversity of the methods employed in harvesting mainly depends upon the extent of the crops and the price of labour.
Connected with this branch of our subject is the method of storing corn. Some persons recommend that granaries should be built for the purpose at considerable expense, the walls being made of brick, and not less than three[600] feet thick; the corn, they say, should be let in from above, the air being carefully excluded, and no windows allowed. Others, again, say that the granary should have an aspect in no direction but the north-east or north, and that the walls should be built without lime, that substance being extremely injurious[601] to corn; as to what we find recommended in reference to amurca of olives, we have already mentioned it on a former[602] occasion. In some places they build their granaries of wood, and upon pillars,[603] thinking it the best plan to leave access for the air on every side, and from below even. Some persons think, however, that the grain diminishes in bulk if laid on a floor above the level of the ground, and that it is liable to ferment beneath a roof of tiles. Many persons say, too, that the grain should never be stirred up to air[604] it, as the weevil is never known to penetrate beyond four fingers in depth; consequently, beyond that depth there is no danger. According to Columella,[605] the west wind is beneficial to grain, a thing that surprises me, as that wind is generally a very parching[606] one. Some persons recommend that, before housing the corn, a bramble-frog should be hung up by one of the hind legs at the threshold of the granary. To me it appears that the most important precaution of all is to house the grain at the proper time; for if it is unripe when cut, and not sufficiently firm, or if it is got in in a heated state, it follows of necessity that noxious insects will breed in it.