We are what we crop? – Part 2

Jacob van Etten continues our coffee-table conversation about whether crops determine everything.

All of this started off with Wittfogel’s Oriental despotism and how crops (rice) and cropping technologies (irrigation) give shape to whole societies. Jeremy mentioned Malcolm Gladwell, who argues in Outliers that Asians are good in math because they grow rice. Crops determine everything?

Wittfogel first. Some more recent opinions nuance the point about hierarchical rice societies. Yes, irrigation tends to give rise to more hierarchical societies. Dorian Fuller and Ling Qin write that the rise of water management in China in archaeological times went hand in hand with the development of social hierarchies.1 But rice irrigation is not as hierarchical as if Henry Ford had organized it. A lot of ‘participation’ goes on, as most water management ultimately relies on the efforts of both big and small players. Francesca Bray writes:

One of the main arguments that underlies such theories is that only a highly centralised state can mobilise sufficient capital and technical and administrative expertise to construct and run huge irrigation systems. It is certainly true that both Hindu and, later, Buddhist monarchs all over Southeast Asia saw it as part of their kingly role, an act of the highest religious merit, to donate generously from the royal treasuries to provide the necessary materials and funding. But kings were not the only instigators of such works. Temples, dignitaries, or even rich villagers often gave endowments to construct or maintain irrigation works on different scales.

Malcolm Gladwell actually argues something similar:

By the 14th and 15th centuries, landlords in central and southern China had a nearly hands-off role with their tenants, collecting only a fixed amount and letting farmers keep whatever yields they had left over. Farmers had a stake in their harvest, leading to greater diligence and success.

Rice, of course, does shape particular societies, but hierarchy is not their only characteristic. Anthropologists who have studied rice farming also emphasize the technological skill that goes into it.2 Transplanting rice seedlings and seed selection in the field need trained hands and keen eyes. Agricultural development in rice-based agriculture therefore means that people get more skilled in the more intensive use of relatively small plots of land. That’s actually close to Malcolm Gladwell’s point about rice and math, so perhaps he isn’t far off. Rice isn’t grown in Asia only, though, and the ultimate test would be to see if West African rice growers, who have a long history of growing the crop, are also good at math.

Maize is completely different from rice in this respect. Sheldon Annis’ typification is very to the point.3 He writes that Mesoamerican maize farming is about making the best use of ‘marginal resources’, those moments or things that cannot be used in different ways: the scraps to fertilize the field, a Saturday afternoon to do some weeding (or perhaps it’s the only thing grandpa can still do). And the crop is robust enough to survive when these resources aren’t around and a round of weeding is skipped or fertilization has been somewhat less than generous. Expansion and contraction is possible and no tight organization of activities is needed to keep things going.

Certain skills are also less important in maize growing though. I went to study maize farming in Guatemala with the idea that maize seed selection would be very important, like it is in rice. But in maize, seed selection doesn’t have much to do with genetic improvement. Farmers select because they want seed of good physiological quality, but they have very few expectations about genetic change. Maize is an outbreeder and genetic change is so slow that much patience and observation are needed to track genetic change over time. That is why maize breeders needed to invent inbred-hybridization to start making some real progress on maize improvement. In favour of maize you could say that it is very robust. Populations are diverse enough to mold themselves to changing conditions, while rice needs constant attention of seed-selecting farmers to be adapted.

While rice farmers invest in laborious and sophisticated plant and water management techniques and maize farmers take a hands-off approach, wheat farmers take yet another road: let others do the work. Medieval inventions made it possible to make the animals do the plowing, until the tractor took over in the twentieth century. Now less than 5% of the European population works in agriculture.

So rice, maize and wheat shape very different societies. But all of this doesn’t depend on the crop itself perhaps? The Corn Belt shows that you can do the tractor thing without the wheat. But, interestingly enough, temperate maize is being reshaped into something ever more similar to wheat. A lot of breeding has made the crop more suitable for mechanical harvesting, like wheat. More dramatically from a biological point of view, maize has practically become an inbred crop. Since hybrid vigor is declining and the inbred lines catch up with the hybrids, Corn Belt farmers may one day end up growing purely inbred maize instead of hybrids. Just like wheat.

So we are what we crop, partly because we crop what we are.

  1. D.Q. Fuller & L. Qin. 2009. Water management and labour in the origins and dispersal of Asian rice. World Archaeology 41(1): 88-111. []
  2. F. Bray. 1986. The Rice Economies. P. Richards. 1996. “Agrarian creolization.” In: R. Ellen and K. Fukui, eds. Redefining nature. []
  3. A. Sheldon. 1987. God and Production in a Guatemalan Town. []

2 Replies to “We are what we crop? – Part 2”

  1. True. Farmers doing recurrent selection (after being taught to do so by extensionists) have been quite successful. But traditional maize farmers are not known to do this normally. This is because short term genetic changes are not readily observable to a farmer working under heterogeneous farming conditions. Work by Daniela Soleri and David Cleveland shows that traditional maize farmers have no strong concept of genetic change in maize.

    Inbred lines catching up with hybrid varieties in maize is based on my interpretation of statistics presented by the late Donald Duvick (page 6):

    Heterosis probably will contribute increasingly smaller proportions to total yield gains in years to come, because of proportionately higher rates of improvement in inbred yield.

    That we will be planting inbreds some day is a far stretch, but hey, we´re at the coffee table.

  2. I have to disagree with “genetic change is so slow [in maize]”. Maize can be improved very quickly with recurrent selection, depending on how much variability is present in the population you’re starting with. I have some populations that I’m working with that have shown statistically significant changes after just one 2 cycles of selection. You can even select on more than one trait at once. I’d also argue that maize isn’t necessarily an outbreeder. Much of the heavy pollen from a maize plant falls from a tassel right down on to it’s own ears. Finally, do you have any evidence of the decline of hybrid vigor? I haven’t heard anything like this. In fact, I’ve heard that maize breeders have been developing new heterotic groups based on tropical germplasm, so there may even be enhanced hybrid vigor. Hmmm.

Leave a Reply

Your email address will not be published. Required fields are marked *