I don’t know how often they did it, but the nasty Romans would salt the fields of their defeated enemies. Apparently crops could not grow on fields that were salted.
My question is, how is this done? How much salt is needed? How much time? Surely the rain would wash the salt away eventually. How many years until crops could grow again?
Also, the Netherlands drained shallow ocean areas to increase farmland. How did crops grow in these areas?
Thanks.
Bottom line, it was not used as a method of destroying cropland. When it was done, it was done as a sort of ritual curse. Note that while the Romans symbolically leveled Carthage after the Punic Wars, it was soon rebuilt and became an important roman province.
we’ve discussed the salting man times on this Board. I find it hard to believe that, if any salting was done, it was probably only over a small area, and mostly symbolic. Spreading salt to prevent plant growth requires a lot of salt – it’s worse than planting grass seed. And salt wasn’t cheap in most places (Read Mark Kurlansky’s book Salt sometime).
Even if they did it, it would be of questionable value. I don’t know how long it took reclaimed land in the Netherlands, but in the Salt Lake valley in Utah, which used to be the bottom of salty Lake Bonneville – saltier than the ocean – settlers had to cope with salt-infused soil. They were able to deal with it by hauling down unsalted "Sweet Soil’ from above the Benches (what used to be the beaches of Lake Bonneville) and watering a LOT.
Today, you would never guess that the Salt Lake City valley had been the bottom of a salt lake. It’s had the advantage of a century and a half of irrigation, and pretty intensive and constant irrigation over the past century.
Salt was a valuable commodity back in Roman Times, and it’s pretty unlikely that they would destroy equally valuable farmland by literally pouring money on it.
As for the Netherlands, it’s all dykes and windmills.
If you dig a ditch and allow water to drain into it, the drainage water will naturally have a much higher salinity content than the surrounding soil. The windmills then pump the water back to the sea.
Looks like it takes a heck of a lot of salt to have any effect. Cecil estimates you need 31 tons per acre to reduce yield by 75%.
Say you wanted to do this to a conquered city. Suppose the city is the size of Rome, and it will do to salt the city itself and not the outlying farmlands. Rome has an area of 496 square miles, according to Google. You’d need 9.8 million tons of salt to do the job, about 8.8 million tonnes, according to some quick calculations.
That’s a significant fraction of the current salt production of a major salt-producing country. The top salt producing country in the world today, China, produced 62 million tonnes of salt in 2012. You’d need one seventh of that to salt the city. And that’s the salt production of a large, modern country- I think it’s pretty safe to assume that Rome didn’t produce that much salt in a year. Where is all this salt coming from? How are you getting it all to your targeted city? And we’ve only salted the city itself- we haven’t gotten the outlying areas where a significant portion of the food is probably actually grown.
How long will the effects of this last? I suspect that, if your targeted city gets significant rainfall, not long. Otherwise we’d probably have problems in cities in the northeastern US where salt gets put on the roads several times every year.
At the height of the Roman empire, a huge percentage of their grain was grown in North Africa. So, suffice it to say that either the Romans didn’t salt much Carthaginian land or that salting the fields doesn’t render them infertile for very long.
They couldn’t possibly have salted much land. My calculation was for salting an area the size of the city of Rome. That’s not even a significant fraction of Italy, let alone of North Africa.
Although, why they’d want to is another question. Carthage’s strength was in its ships and trade and the Romans knew that.
No special expertise in this area, but wouldn’t the salting have been a short term thing to just drive the inhabitants of the area away? I mean, if you are a subsistence farmer, just one year of unworkable soil is enough to send you into famine or economic ruin and force you to seek “greener pastures” so to speak…
As far as Carthage is concerned, there doesn’t seem to be any mention of the salt thing in contemporary or close-to-contemporary sources, so I think the best bet is that the story was invented later. Or, at least, a ritual sprinkling of salt was blown up to “sowing fields with salt so that nothing would grow there again” proportions. Which also, as demonstrated by several posters above, makes by far the most sense in terms of logistics.
The story does have some truth to it in it terms of spirit, though, if not in fact: The Romans really, really didn’t like the Carthaginians.
I was taught in grade school that they planted celery to absorb the salt in the reclaimed soil.
If you trade for most of your food, though, that’s not going to work. They don’t grow crops in Venice, for example, but they’ve managed to keep the city a going concern for over a thousand years.
In fact, the standard theory about the origins of Venice is that refugees from Aquileia and neighboring cities set up shops on islands in the lagoon, for safety, to get away from Huns who were destroying their homes in the fifth century. So their priorities for what counted as “greener pastures” clearly didn’t include fields.
Given that you would need multiple tons of salt to affect even one acre of farmland, it would be a lot easier just to massacre everyone.