1/16/19 Smil first half of ch. 3
the history of agricultural technology is a
history of finding ways to increase land productivity to support
larger populations
bit theme: increased energy returns (for a given amount of human
energy how much do you get) as a result of technological
advances
but it is more complicated eg. different forms of energy aren't
easily interchangeable
grains are energy-dense and easy to store
people don't necessarily choose to adopt new methods of
farming--they have other choices
getting more productivity from the same land usually means using
more energy (in this chapter human or animal)
why might you improve your farming technology beyond what is
currently working
- because population has
increased
- so you can sell it
- buy more fertilizer or
technology to grow even more
- buy things
- it makes your work easier
pem photo from Cuba
Is simple agriculture sustainable?
- only if you don't deplete the soil of its nutrients
- is there enough water or are you using up groundwater
- are you building up salt in the soil
the steps of traditional farming:
- plowing with oxen video
- harrowing
- seeding
- cultivating to remove weeds
- harvesting with a sickle
or scythe
- threshing and winnowing to separate the grains
- milling grain into flour
- baking (or cooking grain into a porridge such
as modern hot cereals)
the importance of legumes (beans, peas and lentils)
- nitrogen fixing
- complementary amino acids to get complete proteins
Intensification
- animal labor
- harnessing
- how much feed does the animal need?
- irrigation: very labor intensive but can have
high return
- fertilization
- macronutrients: nitrogen, phosphorus,
potassium
- crop residues were often used for other
purposes
- manure was labor intensive--required over 10
tons per hectare (an acre is .4 hectare, a metric ton is 11%
more than a US ton)
- nitrogen-fixing crops (called green manure
if you just plow them under): peas, beans, lentils, clover,
alfalfa, vech, peanuts
- growing a wider variety of crops and crop
rotation