Agriculture Reference
In-Depth Information
management time. Fernandez-Cornejo
et
al
. (2005) showed that the saved manage-
ment time for US soybean farmers
translated into higher of -farm incomes.
Moreover, farmers are heterogeneous; that
is, many adopters have benei tted in spite
of zero or negative mean proi t ef ects. h e
average farm-level proi ts seem to have
increased over time, due partly to seed
price adjustments and farmer learning
ef ects.
In South America, the average proi t
ef ects of HT crops, especially HT soybeans,
are larger. While the agronomic advantages
are similar to those in North America, the
fee charged on seeds is lower. h e reason for
this is that HT soybean technology is not
patented in most South American countries.
Many soybean farmers in Brazil and
Argentina use farm-saved GM seeds. Qaim
and Traxler (2005) showed for Argentina
that the average proi t gain through HT
soybean adoption was in a magnitude of
US$23/ha (see Table 14.1). h e technology
is so attractive for farmers that HT is now
used on almost 100% of the Argentine
soybean area. In Paraguay and Uruguay,
adoption rates of HT soybeans are similarly
high; in Brazil, this technology was adopted
on 88% of the national soybean area in 2012
(James, 2012).
While farmers in these middle-income
countries benei t signii cantly from HT
soybeans, most soybean growers operate
relatively large-scale and fully mechanized
farms. So far, HT crops have not been widely
adopted in the small farm sector of
developing countries. Smallholders often
weed manually, so that HT crops are
inappropriate, unless labour shortages or
weeds that are dii cult to control justify
conversion to chemical practices. In some
regions of Asia and Africa, smallholder
farmers have switched to the so-called
system of rice intensii cation (SRI), where
rice is grown with intermittent irrigation
under aerobic conditions. h is saves water
and is associated with less greenhouse gas
emissions, but problems with weeds tend to
increase. Under such conditions, HT rice
might be an interesting alternative.
Adoption of HT crops does not lead to
reductions in herbicide quantities in most
cases, but selective herbicides, which are
often relatively toxic to the environment,
are substituted by less toxic broad-spectrum
herbicides (see Table 14.1). Glyphosate, for
instance, has little residual activity and is
decomposed rapidly to organic components
by microorganisms in the soil. According to
the international classii cation of pesticides,
it belongs to toxicity class IV, the lowest
class for 'practically non-toxic' pesticides.
Also, the reduction in tillage operations and
the expansion of no-till practices through
HT technology adoption brings about
environ mental benei ts in terms of a reduc-
tion in soil erosion, fuel use and greenhouse
gas emissions (Brookes and Barfoot, 2012).
On the other hand, weed species might
develop resistance to glyphosate and other
broad-spectrum herbicides, which would
require increasing amounts of pesticides to
be applied. Glyphosate resistance in certain
weed species has already been reported in
some locations. Furthermore, the high
proi tability of HT soybeans has led many
farmers in Argentina and Brazil to convert
bush and grass land into soybean land and
cultivate the same crop year after year.
Although the soybean area in these countries
has been growing over the past 20 years,
growth has accelerated since the introduction
of HT technology. Area conversion and
soybean monocultures might contribute to
biodiversity loss and other environmental
problems. h ese are not technology-
inherent risks, as they would occur in any
situation where the proi tability of one
particular crop increases considerably. But
appropriate policies and regulations are
required to avoid negative environmental
ef ects.
Insect-resistant GM crops grown com-
mercially so far involve dif erent genes from
