Crop Yields: The Green Revolution

The agricultural advancements initiated by Norman Borlaug in Mexico in 1943 were deemed a success, leading the Rockefeller Foundation to extend these methods to other nations. Mexico's Office of Special Studies evolved into an informal international research centre in 1959, and by 1963, it was formally established as CIMMYT (International Maize and Wheat Improvement Centre).

In 1961, India was on the brink of a severe famine. M. S. Swaminathan, an adviser to India’s Minister of Agriculture, invited Borlaug to help. Despite bureaucratic challenges posed by India’s grain monopolies, the Ford Foundation and Indian government worked together to import wheat seeds from CIMMYT. Punjab, chosen for its dependable water supply and agricultural success, became the first region to trial these new crops. India launched its own Green Revolution programme, focusing on plant breeding, irrigation development, and agrochemical financing.

India also adopted IR8, a semi-dwarf rice variety developed by the International Rice Research Institute (IRRI). In 1968, Indian agronomist S.K. De Datta discovered that IR8 produced five tonnes of rice per hectare without fertiliser and nearly 10 tonnes with optimal inputs—ten times the output of traditional rice. IR8, dubbed “Miracle Rice,” spread rapidly across Asia and eventually led to the creation of semi-dwarf IR36.

During the 1960s, rice yields in India averaged around two tonnes per hectare. By the mid-1990s, they had risen to six tonnes per hectare. The price of rice, which stood at about $550 per tonne in the 1970s, dropped to under $200 per tonne by 2001. By 2006, India had become one of the world's major rice exporters, shipping nearly 4.5 million tonnes globally.

Green revolution technologies

The Green Revolution promoted technologies that already existed but had not been widely adopted outside industrialised nations. These included pesticides, irrigation systems, synthetic nitrogen fertilisers, and improved crop varieties. One of the key innovations was the development of high-yielding varieties (HYVs) of maize, wheat, and rice. HYVs had a higher capacity to absorb nitrogen, but cereals that absorbed more nitrogen were prone to lodging (falling over before harvest). To address this, semi-dwarfing genes were bred into them. A Japanese dwarf wheat cultivar, sent to Washington, D.C. by Cecil Salmon, played a crucial role in the development of Green Revolution wheat.

Advances in molecular genetics identified the mutant genes responsible for reduced-height traits in wheat and rice, linked to gibberellin biosynthesis or signalling genes. Shorter plants, being mechanically more stable, diverted energy from stem growth to grain production, amplifying the impact of chemical fertilisers on yield.

However, HYVs only outperformed traditional varieties when sufficient irrigation, pesticides, and fertilisers were available. Without these inputs, traditional varieties could sometimes yield better results. Critics argue that the apparent superiority of HYVs is valid only in the context of monoculture, while traditional varieties thrive in more diverse, polycultural systems.

Impact on production

Between 1961 and 1985, cereal production more than doubled in developing countries, with steady increases in the yields of rice, maize, and wheat. These production gains are largely attributed to improvements in irrigation, fertilisers, and seed varieties, especially in Asian rice cultivation.

Despite the increase in agricultural output, the energy input required to produce crops also rose, reducing the efficiency of crop production relative to energy use. Green Revolution techniques rely heavily on chemical fertilisers, herbicides, and pesticides, many of which are derived from fossil fuels. Proponents of the Peak Oil theory fear that a future decline in oil production could lead to food shortages or even a Malthusian crisis.

Effects on food security

The impact of the Green Revolution on global food security is complex. The world’s population has increased by approximately four billion since the Revolution began, and many believe that without it, widespread famine and malnutrition would have been far worse. For example, India’s wheat production surged from 10 million tonnes in the 1960s to 73 million tonnes by 2006. Average daily caloric intake in developing nations has increased by roughly 25%, and between 1950 and 1984, global grain production more than doubled.

The Green Revolution is credited with preventing famine and feeding billions. However, some argue that it has reduced food security for many by shifting cropland from subsistence farming to the production of grains for export or animal feed. In India, for instance, land previously used to grow pulses, a dietary staple for peasants, was converted to wheat production, which was less integral to their diets.

Environmental Impact

Pesticides

Green Revolution farming depends heavily on the use of pesticides to protect crops from pests, which are common in monocropping—the practice of cultivating a single crop over large areas.

Water usage

High-yielding varieties are also extremely water-intensive. In the United States, agriculture accounts for 70% of fresh water consumption, and the Southwest region, which uses 36% of the nation’s water, receives only 6% of its rainfall. Irrigation relies partly on non-renewable underground aquifers, such as the Ogallala, which is being depleted faster than it can be replenished. Rivers like the Yellow River in China and the Ganges in India are also drying up due to agricultural demands, and the Aral Sea has lost much of its area and volume due to water diversion for cotton production.

Water quality

Water quality has suffered as well. Salinisation in the Aral Sea has wiped out native fish, leaving local economies more reliant on the very agricultural model that caused the problem. Nitrogen-intensive fertilisers also contribute to algae blooms that deplete oxygen in waterways, creating “dead zones” that kill fish and other aquatic life. Most incidents of water runoff are linked to small-scale family farms, often organic-based.

Biodiversity

The Green Revolution has significantly reduced agricultural biodiversity by focusing on a few high-yield crop varieties. This raises concerns about the vulnerability of crops to pests and diseases that cannot be controlled with agrochemicals, as well as the permanent loss of valuable genetic traits in traditional varieties. Seed banks, such as the International Plant Genetic Resources Institute, have been established to address these concerns and preserve genetic diversity.

Opinions are divided on the Green Revolution’s impact on wild biodiversity. Some argue that by increasing yields per unit of land, agricultural expansion into new areas has been limited. Others contend that it has led to deforestation and habitat loss, as land degradation and nutrient depletion have forced farmers to clear previously forested areas to maintain production. For example, the development of wheat varieties tolerant to acidic soils with high aluminium content has facilitated the spread of agriculture into the Brazilian Amazon.

Despite this, the international community has recognised the negative consequences of agricultural expansion. The 1992 Rio Treaty, signed by 189 nations, led to the creation of Biodiversity Action Plans, which highlight the role of agriculture in biodiversity loss.