Short answers, pulled from the story.
Farms in Rome measured between 18 and 108 iugera, which equals about 0.65 acres or a quarter of a hectare. These early holdings were small and family owned before large estates emerged later.
Common wheat and durum wheat were introduced to Italy around 450 BC according to Varro. Durum hard wheat became the preferred grain because it baked into leavened bread and grew easier in the Mediterranean region than soft wheat.
David Mattingly and Gregory Aldrete calculated that 17 ships arrived daily from April to September covering four months totaling 100 days. Each ship carried products with an average load of 250 tonnes to feed the population of Rome estimated at one million people.
The most impressive remains occur at Barbegal in southern France near Arles where sixteen overshot water wheels arranged in two columns operated from the end of the 1st century AD until about the end of the 3rd century. Capacity of these mills has been estimated at 4.5 tons of flour per day sufficient for bread for 12,500 inhabitants occupying Arelate.
Main texts come mostly from Roman agronomists including Cato the Elder Columella Marcus Terentius Varro and Palladius. Cicero considered farming best of all Roman occupations declaring none more profitable or delightful than agriculture.