In the grain-growing area of north Africa, centered on the ancient city of
Carthage, a family of six people needed to cultivate 12
iugera/ 3
hectares of land to meet minimum food requirements (without animals). If a family owned animals to help cultivate land, then 20 iugera was needed. More land would be required to meet subsistence levels if the family farmed as
sharecroppers. In
Africa Proconsularis in the 2nd century AD, one-third of the total crop went to the landowner as rent For yields of wheat, the number varies depending on the ancient source. Varro mentions 10:1 seed-yield ratio for wheat as normal for wealthy landowners. In some areas of Etruria, yield may have been as high as 15:1. Cicero indicates
In Verrem a yield of 8:1 as normal, and 10:1 in exceptionally good harvest. Paul Erdkamp mentions in his book
The Grain Market in the Roman Empire, that Columella was probably biased when he mentions a much lower yield of 4:1. According to Erdkamp, Columella wanted to make the point that "grain offers little profit compared to wine. His argument induces him to exaggerate the profitability of vineyards and at the same time to diminish the yields that were obtained in grain cultivation. At best Columella provides a trustworthy figure for poor soils; at worst, his estimate is not reliable at all." Average wheat yields per year in the 3rd decade of the 20th century, sowing 135 kg/ha of seed, were around 1,200 kg/ha in Italy and Sicily, 1,710 kg/ha in Egypt, 269 kg/ha in
Cyrenaica, Tunisia at 400 kg/ha, and Algeria at 540 kg/ha, Greece at 620 kg/ha. This makes the Mediterranean very difficult to average overall. An agricultural unit was known as a
latus fundus mentioned by
Varro as a great estate, which can be interpreted as a
latifundia or at 500
iugera or around 125 hectares because this is the land limit imposed by
Tiberius Sempronius Gracchus as tribune in 133 BC. With the incorporation of
Egypt into the Roman empire and the rule of the emperor
Augustus (27 BC-14 AD),
Egypt became the main source of supply of grain for Rome. By the 70s AD, the historian
Josephus was claiming that Africa fed Rome for eight months of the year and Egypt only four. Although that statement may ignore grain from Sicily, and overestimate the importance of Africa, there is little doubt among historians that Africa and Egypt were the most important sources of grain for Rome. To help assure that the grain supply would be adequate for Rome, in the second century BC, Gracchus settled 6,000 colonists near Carthage, giving them about each to grow grain. Grain made into bread was, by far, the most important element in the Roman diet. Several scholars have attempted to compute the total amount of grain needed to supply the city of Rome. Rickman estimated that Rome needed 40 million
modii (200,000 tonnes) of grain per year to feed its population. Erdkamp estimated that the amount needed would be at least 150,000 tonnes, calculating that each resident of the city consumed of grain per year. The total population of Rome assumed in calculating these estimates was between 750,000 and one million people. David Mattingly and Gregory Aldrete estimated the amount of imported grain at 237,000 tonnes for 1 million inhabitants; This amount of grain would provide 2,326 calories daily per person not including other foods such as meats, seafood, fruit, legumes, vegetable and dairy. In the Historia Augusta, it is stated Severus left 27 million modii in storage - considered to be a figure for the canon at the end of the 4th century and enough for 800,000 inhabitants at 500 lbs of bread per person per annum
Pliny the Younger painted a picture that Rome was able to survive without Egyptian wheat in his speech the
Panegyricus in 100 AD. In 99 there was an Egyptian crisis due to inadequate flooding. Pliny the Younger stated that for "long it was generally believed that Rome could only be fed and maintained with Egyptian aid". However, he argued that "Now [that] we have returned the Nile its riches... her business is not to allow us food but to pay a proper tribute. ==Mechanization==