of people working in factories instead of in agricultural fields. Factors that
created the Second Agricultural Revolution included:
■ New crops came into Europe from trade with the Americas (e.g., corn and
potatoes).
■ The passage of England’s Enclosure Act encouraged the consolidation of
fields into large, single-owner holdings.
■ Methods of soil preparation, fertilization, crop care, and harvesting
improved.
■ There were advances in breeding livestock.
■ The invention of the seed drill allowed farmers to avoid wasting seeds and
to plant in rows.
■ Increased agricultural output made it possible to feed large, urban
populations.
■ Railroads allowed prairies in the United States to develop into individual
farms.
■ The invention of the tractor, combined with other farm machinery,
improved efficiency on the farms.
■ New banking and lending practices helped farmers afford new equipment
and seed.FIRST GREEN REVOLUTION (1950–1970)
The first “green revolution” occurred between 1950 and 1970. It involved
planting monocultures, using high applications of inorganic fertilizers and
pesticides, and the widespread use of artificial irrigation systems. Before the first
green revolution, crop production was correlated with an increase in acreage
under cultivation. After the first green revolution, crop acreage increased about
25%, but crop yields increased 200%. Crop yields then reached a plateau since it
was easier and more economical to increase crop production through various
agricultural techniques than to buy and clear new land.
SECOND GREEN REVOLUTION (1970–PRESENT)
The second “green revolution” began during the 1970s and is still continuing
today. It involves growing genetically engineered crops that produce the most
yields per acre. It is in contrast with past agricultural practices in which farmers
planted a variety of locally adapted strains. For example, of all wheat grown in
the United States today, 50% comes from 9 different genotypes.