The Best Australian Science Writing 2014 (7 page)

Organic agriculture hasn't found a way around the problem: farm animal waste only spreads so far. ‘But what that creates, in my mind, is a niche where those animal wastes are recycled, because if they aren't brought back into agriculture then they are a huge environmental waste problem,' Adamchak says. ‘So organic is a relatively small part of the whole, but it is an important part.'

In the developed world, only around 65 per cent of manure is currently reused to fertilise croplands, says CSIRO chief research scientist Mario Herrero, a livestock expert who has studied agricultural nitrogen flows. In the developing world, where a subsistence farmer might have a couple of cows, all the manure will be used on his or her crops, although it will only supply about half of the nitrogen the crops ideally need, notes Herrero. The challenge to using more of it on the large, industrialised farms of the developed world is getting it to where it is needed. Manure is heavy, bulky stuff, expensive to store and transport. ‘In the developing world it is a precious resource but in the developed world it is seen as a waste product.'

* * * * *

It would be easy to dismiss organic food production as insignificant, especially at a time when the population is rocketing and climate change is adding to the challenge. Yields drop when switching to organic, and there isn't enough organic fertiliser to go around anyway. But dig a little deeper and it seems that organic farming's roots have been spreading.

Navin Ramankutty at McGill University in Canada co-authored the 2012
Nature
paper comparing organic yields with conventional. Although the headline finding was that organic crop yields were 25 per cent lower than conventional yields, for some crops there was almost no gap. ‘Organic seems to work very well for legumes, and for perennials – tree crops, things like apples,' he says.

Why do legumes and tree crops do so well under organic cultivation? Legumes fix their own nitrogen from the soil, and tree crops can spread their deep roots wide in search of water and nutrients. If organic can play a limited role in global food production, these are the crops that we should focus organic production on, Ramankutty says. ‘It makes sense to use organic where it works best.'

Ramankutty comes at the question of sustainably feeding the growing population by stepping back and looking at the global picture. In terms of its environmental impact, agriculture is the match of any heavy industry, he says. It has a large carbon footprint, is the biggest driver of biodiversity loss, the biggest user of water, and the biggest polluter of water – just to name a few of its consequences. ‘I work on two main thrusts,' he explains. ‘One, simply to characterise agricultural practices globally, and then using these data to help answer the question of how we can do agriculture better.'

Organic agriculture isn't necessarily agriculture done better, he adds. ‘I'm not convinced yet that organic is a more sustainable way to farm.' Water pollution is a particular concern, due to the
run-off from manure, which is more easily leached from the soil than pellets of synthetic fertiliser. But then, much conventional agriculture still leaves a lot to be desired, particularly because of fertiliser overuse. ‘We are not doing conventional agriculture in a smart way right now, doing monoculture with intensive chemical inputs,' he says. ‘I think the philosophy behind organic offers lessons that conventional agriculture could benefit from.'

Ramankutty is not alone in this vision for a form of agriculture that looks strikingly like organic food production, but with the addition of careful chemical inputs and the inclusion of GM crops. Another proponent is Richard Roush, dean of the School of Land and Environment at the University of Melbourne. Roush was recruited to the cause of agriculture after reading Rachel Carson's 1962 book,
Silent Spring
, which rang alarm bells over the impact of insecticides such as DDT on birds and the environment at large. He trained as an entomologist to find more environmentally friendly ways of combatting insect pests.

For several years in the mid-2000s, he led the team responsible for promoting organic agriculture and other sustainable agriculture programs at the University of California. These days, based in Melbourne, Roush is a regular media commentator. He's earned a reputation as ‘pro-GM', although that's not an accurate portrayal, he tells me. ‘There's just so much crap spoken about GM that I can't restrain myself from correcting the facts on it from time to time.'

His time in California is certainly evidence of an open mind. ‘I didn't find that to be a challenge to my psyche in any way,' he says. ‘The conclusion I came to was that organic should be congratulated for a kind of bioprospecting – looking for new ways to address issues in agriculture, and coming up with a lot.' Legume cover crops are a great example, he says. Grown either in fallow seasons or as an understorey to food crops, they protect soil from being blown or washed
away while supressing weeds and pests and adding nitrogen.

But, like Ramankutty, Roush is keen to give examples of organic practice where he believes synthetic chemicals would be better. While he was working in the US, there was growing evidence that farm workers in organic vineyards were developing respiratory problems because of the amount of sulphur – a ‘natural' chemical allowed under organic production standards – being used to protect the grapes against powdered mildew fungus, he says. ‘I came to the view that this was more dangerous to farm workers than a bit of use of the modern fungicides called ergosterol biosynthesis inhibitors, which have extremely low mammalian toxicity.

‘I think the future of agriculture will be to pick the eyes out of the best techniques used by organic growers, but allow ourselves the opportunity to use synthetic inputs where they are reasonably safe,' he adds. ‘The enormous challenges we have in growing crops are such that you wouldn't want to arbitrarily tie one or both arms behind your back.'

By the time I talk to renowned food sustainability and ecology expert Rudy Rabbinge at the University of Wageningen in the Netherlands, the message is becoming familiar. ‘Organic farming is based on bans on fertilisers, pesticides and GMOs,' he tells me. ‘I'm not saying that you should promote use of these things, but to eliminate them completely is in my opinion stupid.'

By using them with care and a sound understanding of their effects, he says, ‘you see high productivity, very low environmental impact, and systems contributing to human health.'

Rabbinge's comments resonate with an old idea known as integrated pest management (IPM), the concept that liberally dousing croplands with chemicals is not the only – or the best – way to control weeds, crop diseases or troublesome insects. Some form of IPM is now practised in the majority of conventional farms, even if only in a form as basic as rotating crops, or spraying
with pesticide only when insect pest populations exceed a certain density.

For some pests, IPM has proven particularly effective. Take the diamondback moth, says Roush. This pest has spread around the world gorging on broccoli, cabbage and other ‘cruciferous' vegetable crops. It is particularly quick to evolve resistance to chemical pesticides.

‘What they are susceptible to, though, are natural enemies,' says Roush. Farmers have had good success by deploying these allies in their fields. Ladybirds love to eat their eggs and larvae, and the diamondback is especially vulnerable to certain parasitic wasps that lay their eggs inside the developing caterpillar, killing them. ‘These can keep the densities of the moth down to reasonable numbers,' says Roush.

The latest step, which Ramankutty and Rabbinge are promoting, is to expand this minimum-input approach to include fertilisers, too. Rabbinge is among the researchers who have been working to establish the benefits of careful nitrogen application. In 2013, for example, he co-authored a paper in the
Wageningen Journal of Life Sciences
reporting on results from a Netherlands mixed crop-livestock farm at Oostelijk Flevoland on land reclaimed from the sea in the 1950s. Best-practice techniques introduced at the farm included planting nitrogen-fixing cover crops in rotation with other crops and innovations such as giving the farm dairy herd a fibre-rich diet that improved herd health and milk output while also improving the quality of their manure for fertilising the fields. Nitrogen use efficiency on the farm rocketed to 73 per cent – far above the 15 per cent efficiency typical of Dutch dairy farms in the mid-1980s when synthetic fertiliser use was at its most lavish – while crop production equalled or exceeded the local average, and the output of the farm's milking cows increased.

And new technologies are now coming into play that will
enable farmers to cut chemical inputs still further. Why spray a whole field with pesticide when only one corner is infested with a pest? On the most forward-looking farms, unmanned aerial drones are already autonomously patrolling the fields, using UV cameras to scan for any small clusters of stressed crops in need of some chemical assistance. Other sensor technologies allow tractors to constantly tailor the amount of chemical sprayed based on plant need.

* * * * *

Stephen Powles is not just a researcher. Eight years ago he took the plunge and bought his own 650-hectare property at Quairading, a two-hour drive inland of Perth. He grows wheat, barley and canola.

As you might expect, Powles' farm does well. ‘We apply state of the art technology,' he says. It starts with the soil, which is never ploughed – a process that wrecks soil structure and releases precious moisture. Instead, satellite technology guides farm machinery to drive the same ‘tramlines' to and fro across the field, preventing heavy tractors and harvesters from compacting the strips of soil where crops grow. Not ploughing means using herbicides to help control weeds, so Powles includes GM herbicide-resistant canola in his crop rotation cycle, which he can spray with herbicide if necessary.

And of course there are the harvest weed control techniques that Powles has helped to pioneer. The fires burning on WA farms after recent harvests hint at a new kind of farming, in which judicious use of chemicals could be combined with organic practices to the benefit of all – better yields, more profitable farms, high quality produce, and the smallest possible environmental impact.

Progress is tangible. For the last few harvests, no springtime fires have been lit on Powles's farm, where they were damaging
his precious soils as well as the wider environment. Instead, his harvesters now funnel the weed seeds directly onto the compacted tramlines his satellite-guided vehicles always follow. Most weed seedlings simply don't survive along this hostile strip of ground.

Powles isn't done with work to improve yields still further. ‘I'm certain that in some cases there would be things that conventional farmers could learn from organic food production,' he says.

Planet of the vines

Massimo's genes

This. Here. Now. The climate catastrophe

John Cook

What climate scientists warned would happen is happening in Australia. Bushfire danger is increasing. Heatwaves are becoming hotter and longer. Sea levels are rising. The Great Barrier Reef is dying. Floods and droughts are intensifying. Human health, agriculture, property, infrastructure and our environment are at greater risk due to human-caused global warming.

Climate change impacts are experienced first through extreme events. Before we notice a gradual increase in average temperature, our attention is grabbed by more intense heatwaves. Before we undergo steadily rising sea levels, we're hit with damaging storm surges. Current extreme weather events are a window into how future climate change will affect us.

When bushfires raged across New South Wales in October 2013, Deputy Greens leader Adam Bandt voiced what climate scientists across the country were already thinking – climate change was increasing the risk of bushfires. Politicians and media figures hyperventilated, but Bandt was merely expressing what had already been established in the scientific literature.

Climate change is an issue that generates a great deal of noise, confusion and, yes, heat. There is little wonder that so much confusion exists among the Australian public since they
are all too often not receiving accurate information about what is happening. An analysis by the Australian Centre for Independent Journalism found that a third of recent Australian media articles covering climate change rejected or questioned the scientific consensus that human beings were causing global warming.

So it is necessary to go back to basics, to remind ourselves what the science tells us about climate change and its impacts on humanity. Will climate change affect us, and if so, how? Is it happening already? Most importantly, is there anything we can do about it?

* * * * *

First, the basic proposition: what is climate change and what causes it?

When we burn fossil fuels such as coal or oil, we emit greenhouse gases such as CO
₂
into the atmosphere. Greenhouse gases are transparent to sunlight. This means that sunlight passes through the atmosphere largely unhindered and warms the Earth. The Earth then attempts to radiate infrared heat back out to space but the greenhouse gases trap some of this heat. That is the dynamic of the greenhouse effect: greenhouse gases act like a one-way mirror, letting sunlight in but trapping heat on the way out.