Agriculture generates 30% of global greenhouse gas emissions, more than all the world’s planes, trains and automobiles combined. With this in mind, Bill Meredith, head of agriculture at the University of Lincoln, describes how the industry is responding to environmental challenges.
How can mankind feed a rapidly growing population without destroying the planet? It is a question that tends to polarise the scientific community, with one camp favouring the intensification of agriculture and the other promoting low input systems such as organic farming.
There is a broad consensus, however, that we require a sustainable system that ensures the efficient use of key resources including fuel, fertiliser and water. Improvements in efficiency of resource use will not only conserve dwindling supplies, but will also reduce pollution and the degradation of rivers and lakes.
It’s hardly surprising that irrigation accounts for the biggest single use of water. The critical role of water in sustaining global food supplies should not be under estimated. Climate change is predicted not only to give rise to greater desertification globally, but also to cause an increase in the frequency of extreme weather events, including the occurrence of drought conditions in more temperate European climes.
In the UK, the Government’s Foresight report calls for “climate-smart” agriculture, which uses less fossil fuels and employs techniques that sequester carbon dioxide, such as growing plants with larger roots and creating a better balance between agriculture and forestry.
Farmers in Eastern England are coping with drought conditions for the second year running. Cropping plans and agronomic practices are being adapted to minimise moisture stress during the growing season.
More drought tolerant crops such as barley are being considered as alternatives to wheat. And where wheat must be grown, faster maturing varieties and those with longer straws, which are less susceptible to stress, are favoured.
Non-inversion cultivation systems are preferable to conventional ploughing systems in terms of retaining soil moisture, and earlier sowing tends to result in better rooted, more resilient crops. The use of organic manure and compost also improves moisture retention and soil structure.
Careful timing of fertilisers and fungicides will also improve drought tolerance. Some of the newer fungicides—the SDHIs and strobilurins—have been found to have physiological effects on crops; research by ADAS shows that treated crops use in the order of 25% less water to produce each tonne of grain.
Over recent decades, the amount of funding that has gone into agricultural research in the UK has declined, but this trend is now being reversed. The Biotechnology and Biological Sciences Research Council (BBSRC) is directing £100m into a food security programme that includes funding from the Department for Environment, Food and Rural Affairs (Defra) and other government departments.
The University of Lincoln is currently researching the use of silicon based products, specifically for improving the drought tolerance of wheat crops. Previous studies have suggested that silicon can alleviate drought stress damage and improve shoot growth. The Lincoln project will show whether improved growth translates into higher yields in drought conditions.
Plant breeding has always played an important role in improving agricultural productivity and there is currently a lot of interest in improving drought tolerance. The Food and Environment Research Agency have recently announced that it will be leading on ABSTRESS, a £2.5m European project designed to improve the way in which pea varieties are bred to resist moisture stress and disease.
The use of genetic modification (GM) to rapidly introduce desirable agronomic traits remains a contentious issue, particularly within Europe. UK scientists at Rothamsted Research, funded by the BBRSC, are currently trialling a GM wheat crop with a novel form of resistance to aphids. The wheat has been modified to produce a non-toxic odour which repels aphids, but attracts their native predators.
More efficient use of water through improved irrigation systems—reducing evaporation and run-off losses—is another priority.
Cranfield University is leading a DEFRA-funded benchmarking initiative to enable farmers to compare their individual field irrigation performance against others to improve efficiency. Improvements could include changing irrigation equipment, installing meters at key control points and better timing of water application.
UK farmers have been quick to embrace the latest technology to improve their productivity. The adoption of precision agriculture systems using GPS technology is a good example of how the industry is responding to the challenge of more efficient resource use by targeting inputs more accurately.
Whether advances in technology and the ‘sustainable intensification’ of agriculture will be sufficient to meet the looming food security crisis remains uncertain, but investing in climate-smart farming that uses resources more efficiently must be a step in the right direction.