sius says that the best manure is that of birds, except
swamp and sea birds,[89] but the best of all is, he claims, the manure
of pigeons because it is the hottest and causes the land to ferment.
This ought to be sown on the land like seed, not distributed in heaps
like the dung of cattle. I myself think the best manure is that from
aviaries in which thrushes and blackbirds are kept, because it is not
only good for the land but serves as a fattening food for cattle and
hogs: for which reason those who farm aviaries pay less rent when the
owner stipulates that the manure is to be used on the farm, than those
to whom it is a perquisite. Cassius advises that the manure next in
value to that of doves is human feces, and third that of goats and
sheep and asses. The manure of horses is of the least value on corn
land, but on meadows it is the best, because, like the manure of other
draught animals fed on barley, it brings a heavy stand of grass. The
manure pit should be near the barn in order that it may be available
with the least labour. If you plant a stake of oak wood in the manure
pit it will not harbour serpents.

2 deg. PLANTING TIME

_Of the four methods of propagating plants_

XXXIX. The second operation, namely that of propagating, must be
considered in relation to the proper time for sowing each kind of
seed, for this concerns the aspect of the field you are to sow and the
season fitting for what you are to plant. Do we not see some things
grow best in the spring, others in summer, some in autumn, and others
again in winter? For each plant is sowed or propagated or harvested in
season according to its nature: so while most trees are grafted most
successfully in spring, rather than the autumn, yet figs may be
grafted at the summer solstice, and cherries even in winter.

And since there are four methods of propagation of plants, by nature
and by the several processes of art, namely: transplanting from one
place to another, as is done in layering vines, what is called cuttage
or propagating quick sets cut from trees, and graftage, which consists
in transferring scions from one tree to another, let us consider at
what season and in what locality you should do each of these things.

_a. Seeding, and here of seed selection_

XL. In the first place, the seed, which is the principle of all
germination, is of two kinds, that which is not appreciable by
our senses and that which is. Seed is hidden from us whe