I will speak of the four principal parts first, and then in detail of the eight subdivisions.
1° CONCERNING THE FARM ITSELF
How conformation of the land affects agriculture
VI. Four things must be considered in respect of the physical characteristics of the farm: its conformation, the quality of the soil, its extent, and whether it is naturally protected. The conformation is either natural, or artificial as the result of cultivation, and may be good or bad in either case. I will speak first of natural conformation, of which there are three kinds: plain, hill and mountain—although there is a fourth kind made up of a combination of any two or all three of those mentioned, as may be seen in many places. A different system of cultivation is required for each of these three kinds of farms, for without doubt that which is suited for the hot plain would not suit the windy mountain, while a hill farm enjoys a more temperate climate than either of the other two kinds and so demands its own system of cultivation. These distinctions are most apparent when the several characteristic conformations are of large extent, as for example the heat and the humidity are greater in a broad plain, like that of Apulia, while on a mountain like Vesuvius the climate is usually fresher and so more healthy. Those who cultivate the lowlands feel the effects of their climate most in summer, but they are able to do their planting earlier in the spring, while those who dwell in the mountains suffer most from their climate in winter, and both sow and reap at later seasons. Frequently the winter is more propitious to those who dwell in the plains because then the pastures are fresh there and the trees may be pruned more readily. On the other hand the summer is more kindly in the mountains for then the upland grass is rich when the pastures of the plains are burnt, and it is more comfortable to cultivate the trees in a keen air.
A lowland farm is best when it is gently sloping rather than absolutely flat, because on a flat farm water cannot run off and so forms swampy places. But it is a disadvantage to have the surface too rolling because that causes the water to collect and form ponds.
Certain trees, like the fir and the pine, flourish most in the mountains on account of the eager air, while in this region where it is more temperate the poplars and the willows thrive best. Again the arbute and the oak prefer the more fertile lands, while the almond and the fig trees love the lowlands.[61] The growth on the low hills takes on more of the character of the plains, on the high hills that of the mountains. For these reasons the kind of crops to be planted must be suited to the physical characteristics of the farm, as grain for the plains, vines for the hills and forests for the mountains.
All these considerations should be weighed separately with reference to each of the three kinds of conformation.
VII. "It seems to me," said Stolo, "that, so far as concerns the natural situation of a farm, Cato's opinion is just. He wrote, you will recall, that the best farm was one which lay at the foot of a mountain looking to the South."
Scrofa resumed: "So far as concerns the laying out of the farm, I maintain that the more appearances are considered the greater will be the profit, as, for instance, orchards should be planted in straight lines arranged in quincunxes and at a reasonable distance apart. It is a fact that, because of their unintelligent plan of planting, our ancestors made less wine and corn to the acre than we do. The point is that if each plant is set with due reference to the others they occupy less land and are less likely to screen from one another the influence of the sun and the moon and the air. This may be illustrated by an experiment: you can press a parcel of nuts with their shells on into a measure having only two thirds of the capacity of what is required to contain them after they have been cracked, because the shells keep them naturally compacted. When trees are planted in rows the sun and the moon have access to them equally from all sides, with the result that more raisins and olives are developed and then mature more quickly, a double result with the double consequence of a larger crop of must and oil and a greater profit."
How character of soil affects agriculture