the first Congress of the International Society of Soil Science (ISSS) in
1927, it was suggested that the world could feed at a maximum 15.9 billion
people although at that time 7.7 billion was considered a more likely
figure. The estimate was largely based on the climatic maps of the world
by Köppen as soil maps of the world were not available. The human
population in 1927 was 1.8 billion of which 72% lived in the temperate
zone. Soil science and food production became closely linked in the 1960s
and the motto for the Seventh International Congress of Soil Science in
1960 in Madison was “Alleviate Hunger, Promote Peace through Soil
In his presidential address R. Bradfield mentioned that he
could think of no single group of scientists who have more to contribute
to feed the world than this group. He also mentioned that agriculturists
including soil scientists have had more experience and in general more
success in increasing food production than population experts have had in
the Second World War when international organisations such as the United
Nations Food and Agricultural Organization (FAO) were established and many
countries were aiming at independence, the feeding of the growing
population became an important area of research. Increasing food
production was a concern in Western Europe because of the devastation
after the war and the baby boom. Fortunately, science came out of the war
with high status and was overall respected. There was great optimism and
positivism in the 1950s and agricultural research rapidly expanded. Most,
if not all, agricultural research was directed towards agricultural
production, which increased dramatically thanks to technological
developments and major investments in agricultural infrastructure. Even
though the term green revolution –
a term coined in 1968 for the agricultural changes that began to spread
through developing countries in the mid-1960s - is mostly being
reserved for agricultural production in developing countries, it could
apply as well to post-war agriculture in Western Europe. There is no doubt
that soil science played an important role in the increase of agricultural
productivity, and Malthus would have been correct predicting that
population growth would outstrip food supplies but for the discoveries of
soil scientists (according to Dennis Greenland).
feeding of the growing population is largely dependent on crop production.
Yields of most crops have increased dramatically in the past century. The
increase has been very rapid since the 1960s, and ever since that time the
rise in yields has taken over from extension of the cultivated area as the
major source of greater food production. The increase in crop yield has
mainly arisen from the fruits of the green revolution. Except for a
doubling or tripling of crop yields, these changes also resulted in less
yield variability. Coefficients of variation for world production of
wheat, rice and maize have fallen from 6-8% in the 1950s to 3-4% in the
1990s, indicating that the greater reliance on yield enhancement has not
increased the instability of food supplies at the global level.
increases in the developing regions have remained below the world average.
Worldwide between 1950 and 1995 yields have increased from 1.1 to 2.8 Mg
ha–1 but yields were lower in the developing regions of the
world. These yield increases were made possible by improved soil
conditions and the availability of crop varieties able to respond to the
better conditions. The improvements are the use of fertilisers and lime,
irrigation and drainage and the effects of these amendments outweighed
soil physical and chemical degradation.
is a decreasing trend in the growth rates of cereal production. The
question arises whether crops have reached their genetic plateau so that
further improvements in soil conditions have no more effect or whether the
stagnation and decline in growth rates is related to soil degradation.
Crop yield decline (or a negative growth rate) may be caused by a range of
factors, including: weed infestation, the invasion of pests and diseases,
genetic decline of the crop, or deterioration of soil chemical, biological
or physical properties. The factors may be interrelated. If crops grow
poorly because of a declining level in available P, weeds or striga may
grow more vigorously and the crop may have less resistance against
diseases, which can cause a decline in crop yields. There is much work
remaining for soil scientists throughout the world!
section is largely based on Chapter 2 from the book "Soil fertility
decline in the tropics, with case studies on plantations".)
Soil fertility decline in the tropics with case studies on
plantations. 360 pp. ISRIC-CABI, Wallingford. [with a
Foreword by Prof D.J. Greenland]. More info
Kauffman, J.H. & A.E.
Hartemink 2003 Soil potential and constraints
for increased agricultural production in the low yield areas of West
Africa. In: People matter: food security and soils. R. Lahmar, M. Held and
L. Montanarella (Eds). Torba, Montpellier pp. 32-43.
Bouma, J. & A.E. Hartemink 2002
Soil science and society in the Dutch
context. Netherlands Journal of Agricultural Science 50: 133-140.
A.E. 2002 Soil science in tropical and temperate regions – Some
differences and similarities. Advances in Agronomy 77: 269-292.
Baren, J.H.V. & A.E. Hartemink 2002 Soil science and the capacity to
feed the world – A historical overview. 17th World Congress of Soil
Science, Vol. II: 622. IUSS, Bangkok.