Global agriculture could have reached limits, says University of Nebraska

PUBLISHED : Saturday, 21 December, 2013, 12:30am
UPDATED : Saturday, 21 December, 2013, 2:59am


Industrial agriculture could be at its limits in its capacity to produce enough to feed an expanding global population according to research published in Nature Communications.

The study by scientists at the University of Nebraska argues that there have been abrupt declines or plateaus in production of major crops which undermine optimistic projections of constantly increasing crop yields.

As much as "31 per cent of total global rice, wheat and maize production" has experienced "yield plateaus or abrupt decreases in yield gain, including rice in eastern Asia and wheat in northwest Europe".

The declines and plateaus in production have become prevalent despite increasing investment in agriculture, which could mean that maximum potential yields under the industrial model of agribusiness have already occurred. Crop yields in "major cereal-producing regions have not increased for long periods of time following an earlier period of steady linear increase".

The paper makes for ominous reading. Production levels have already flattened out with "no case of a return to the previous rising yield trend" for key regions amounting to "33 per cent of global rice and 27 per cent of global wheat production".

Although agricultural investment in China increased threefold from 1981 to 2000, the rate of increase in yields has remained constant for wheat, slowed by 64 per cent for maize and barely changed for rice. Similarly, the rate of maize yield is flat despite a 58 per cent investment increase over the same period.

Factors contributing to the declines or plateaus in production rates include land and soil degradation, climate change and weather patterns, use of fertilisers and pesticides, and inadequate or inappropriate investment.

The research raises critical questions about the capacity of traditional industrial agricultural methods to sustain global food production for a growing world population. Food production will need to increase by about 60 per cent by 2050 to meet demand.

A report from Rabobank in the Netherlands recommends cutting food waste by 10 per cent, as more than 1 billion tonnes, half of which is related to agriculture, ends up as waste.

More efficient use of water is necessary, the report says, such as micro-irrigation, to address a potential water supply deficit of 40 per cent by 2030. Agriculture accounts for 70 per cent of global water demand.

The report also seeks less dependence on fertilisers using "input optimisation" methods designed to reduce the amount of energy and water required.