Feeding the 10 Billion Part 7

FEEDING THE TEN BILLION

PLANTS AND POPULATION GROWTH

L.T. EVANS

CAMBRIDGE UNIVERSITY PRESS                  1998

PART VII

Chapter 7: The Third Billion (1927-1960)

7.1 Introduction: Inputs and interactions

Adding the second billion to the population of the world had taken a century whereas the third billion took only a third as long. Nevertheless, those 33 years encompassed several major innovations and laid the foundations for a profound change in world agriculture.

• By far the most important source of the increase in food supply for the 50% increase in population was still the age-old one of increase in the area cleared for cultivation.
• Between 1927 and 1960 the global arable area was extended from about one billion hectares to 1.4 billion.
• To this increase of 40% we should add an amount for the land no longer used to grow food for draught animals, making the effective increase in arable land for the period about 53%.
• Since then the gains in arable area for been largely balanced by the losses, and the food requirements of the growing population have been met by rising world average yields.
• Reaching a population of three billion in 1960 was, therefore, a major watershed in world agriculture.
• The 1927-1960 period saw the establishment of the FAO and its annual publication of the agricultural statistics on which our global housekeeping can be more securely based.
• It also witnessed the Universal Declaration of Human Rights by the United Nations in 1948, including that to an adequate food supply.

This period is characterized by four other major transformations of agriculture. The first is the increasing dependence of off-farm inputs, still very small in 1927. Since then liquid fuel and electricity have largely replaced men and horses as the source of energy for farm operations as a result of mechanization. Nitrogenous and other fertilizers increasingly replaced farmyard manure. The revolutionary insecticides, fungicides and herbicides quickly came to be relied on for pest and weed control. Even for the seed they sowed, farmers began to look beyond the farm gate, as they had to do for hybrid maize.

Secondly, along with this change went an increasing ‘industrial appropriation of agricultural inputs’, as Goodman, Sorj and Wilkinson put it. They saw the uniqueness of earlier agriculture as having been its confrontation of capitalism with a natural production process to which there was no industrial alternative. However, the innovations discussed in this chapter, and others like them, have led to a flourishing of agribusiness. Mechanization, initially the outcome of ingenious inventions by many farmers, has been taken over by industry, as has the supply of fertilizers and other agrichemicals. The rapid adoption of hybrid maize hastened the industrial appropriation of seed supplies. At the same time, this penetration of agriculture also promoted industrial research for agriculture such as that which led to DDT and many other agrichemicals.

Thirdly, the development of cheap nitrogenous fertilizers for crops made it possible for farmers to abandon the mixed crop/animal husbandry systems which represented the earlier ideal of agriculture – such as the Norfolk four-course rotation – for more specialized crop production systems.

Fourthly, mechanization and the industrialization of agricultural inputs created a great divide in world agriculture between the more developed countries where rising crop yields meant that extension of the arable land could be limited, and the less developed ones still in their demographic transition and with rapidly increasing populations which needed continued land clearing to meet their requirements for food.

• Many kinds of research contribute to the improvement of agriculture. Advances in one sector often prove to be synergistic with those in others, as were mechanization, nitrogenous fertilizers, herbicides and the breeding of hybrid maize.
• Innovations like DDT, 2-4-D and cheap fertilizers which are seen initially as major advances can later become problematic as unforeseen side-effects are exposed.
• The answer is not to abandon agriculture, or fertilizers, or agrichemicals altogether, but to search for solutions, which may require the recognition of public responsibilities and legislative action.
• Finally, as in our earlier steps up the population ladder, famines were still not banished; witness Bengal in 1943 and China in 1959-61 when 30 million people are believed to have died of starvation.

 

7.2 Mechanization replaces men and horses

7.3 Cheaper nitrogenous fertilizers

7.4 Hybrid maize: society wedding or shotgun marriage?

7.5 A heritage of erosion, a hope of conservation

On May 12, 1934 the first dust cloud large enough to cross the USA intact from the parched fields of Kansas, Texas and Oklahoma passed over New York and Washington and swept out to sea. The darkened skies shocked people on the eastern seaboard with the realization that something had gone wrong with the land to the west. In fact, about one third of the arable land of the USA was under threat of erosion at the time.

Soil erosion is as old as agriculture itself, and its history is an integral part of the history of agriculture itself. We saw earlier that the Greeks recognized its causes and its effects, yet did little about it. In the USA William Byrd of Virginia had recorded the severe loss of soil from his tobacco fields as early as 1685. In 1907 when Gifford Pinchot initiated the movement for the conservation of natural resources, soils were among them. However, it was a soil survey in South Carolina in 1911 that provided the first compelling evidence of the extent of erosion on agricultural land.

In 1933 a Soil Erosion Service was established within the US Department of the Interior, but the great American crusader Hugh Hammond Bennett wanted a body that would survive the Depression and commit the federal government to a policy of long-term soil conservation. In early 1935, when he knew another dust storm was on he way, Hammond appeared before the Senate Public Lands Committee just as the dust from the plains arrived. The Senators suspended the hearing for a moment as the sky darkened, and moved to the windows to watch. Soil conservation was clearly a public responsibility. The preamble to the Soil Conservation Act of April 21, 1935 which ensued reads: ‘It is hereby recognized that the wastage of soil and moisture resources on farm, grazing, and forest lands of the Nation, resulting from soil erosion, is a menace to the national welfare and that it is hereby declared to be the policy of Congress to provide permanently for the control and prevention of soil erosion and thereby to preserve natural resources, control floods, prevent impairment of reservoirs … protect public health, public lands and relieve unemployment.’

• The establishment of the Soil Conservation Service under Bennett allowed a comprehensive approach to the problems of soil erosion. The States were encouraged to pass Soil Conservation District laws.

Many interlocking techniques were developed and promoted: contour ploughing, an old practice insisted on by Columbella and other Roman writers but weakened by the advent of the tractor; strip cropping; stubble mulching; wind breaks; subsurface tillage; and greater use of ‘permanent’ pastures. Consequently, when the drought returned in the 1950s, although there was some wind erosion, there were no black blizzards.

• Better rangeland management techniques were developed and the condition of the Dust Bowl rangelands improved.
• On cropped land, the improvements in equipment for cultivation and in techniques for crop residue management have had a major impact on soil conservation, particularly with the development of reduced tillage, ridge-till, strip-till, mulch-till and zero-till techniques.
• Wind erosion has been greatly reduced, but not entirely banished from the Great Plains, as the dust storm of 1989 indicated.

The area of arable land in the USA is 12% greater now than it was in 1930. Faulkner’s indictment of the Plowman’s Folly is occasionally merited when commodity price support programmes or high prices on the international markets tempt farmers to crop areas beyond the long term capacity of their land but, so far at least, The Grapes of Wrath have been avoided.

7.6 Hormones as herbicides: the discovery of 2,4-D

7.7 DDT: the insecticide revolution

7.8 Tissue culture: Trojan horse for things to come

• Gottlieb Haberlandt was the first to consider the purposes and potential of plant tissue culture, in Berlin in 1902, but failed in his own attempts to culture mature grass leaf tissue.
• It was not until 1934 that two rivals in the search, Philip White of the USA and Roger Gautheret of France, both succeeded in getting the survival of plant tissues in culture, using tomato roots and willow cambium respectively.

The next major discovery was of the plant growth substance kinetin, to which cell division is highly responsive. Its addition greatly improved growth media, and Skoog and Miller found in 1957 that callus cultures would form either roots or shoots depending on the auxin/kinetin ratio. The stage was set for controlled organ formation and the regeneration of whole plants from tissues. This was first achieved with carrots in 1958, but it took much longer with many cereals and legumes. The regeneration of whole plants from single cells was first achieved in 1965, with tobacco.

• In 1956 workers in Japan used tissue culture to rescue immature rice embryos.
• In 1960 Cocking, in England, succeeded in removing cell walls in tomato roots with cellulase to isolate naked but viable protoplasts.
• The 1960s also saw the introduction of another culture by Guha and Maheshwari of India.
• During the 1970s the ability to store plant tissue cultures by freeze preservation was developed.

But enough has surely been said to illustrate how one area of what was originally basic research has opened up a continuing stream of opportunities for crop improvement and agricultural benefit. These have evolved from experiments in many different countries, and the synergisms between their findings have led to frequently unforeseen benefits in many different contexts. Truly, as Mr Brooke claimed, science ‘leads to everything; you can let nothing alone.’

Chapter 8: The Fourth Billion (1960-1975)