Writing in issue 2888 of New Scientist, James Mitchell Crow introduces us to the notion that robots will, sooner or later, be tending the crops we depend upon for food, and takes us on a whirlwind world tour of some of the people working to bring this about and some of the technologies that have already been developed.
He begins with Simon Blackmore, of Harper Adams University College, who tells us about robotic technologies that have already found their way into new tractors, implements, and combine harvesters. Blackmore also discusses the energetics of cultivation, saying “Why do we plough? Mainly to repair the damage that we have caused with big tractors. Up to 80 per cent of the energy going into cultivation is there to repair this damage.” He proposes an altogether different approach, using light-weight, autonomous machines. Crow summarizes the requirements list for these machines thusly: “These agribots need to have three key abilities: to navigate, to interpret the scene in front of them, and to be able to help the farmer, by blasting a weed, applying a chemical or harvesting the crop.”
Addressing the first of these requirements, navigation, Crow moves on to Germany, to mention Arno Ruckelshausen of the University of Applied Sciences in Osnabrück, who is developing RTK-GPS, a geolocation technology with a resolution of 2 cm, for BoniRob, a four-wheeled rover that also uses spectral imaging to distinguish green plants from brown soil, and which remembers the location of individual plants and returns repeatedly to each to monitor their growth. Ruckelshausen also intends to equip BoniRob with a precision chemical application system based on ink-jet printer technology, which would apply microdots of pesticide directly to the leaves of weeds. For those averse to using herbiicides in any amounts, Crow mentions flame guns and lasers as alternative methods of weed control. He also goes into the use of a similar approach for fertilizer, using sensors to gauge how much is needed by individual plants and supplying only that much.
The next stopping off point is Australia, where Salah Sukkarieh, of the Australian Centre for Field Robotics, makes the point that funding is relatively abundant for mining and defense projects, but relatively paltry for agricultural robotics, meaning that difficult problems like machine vision will have to be worked out first for other applications first and then reapplied to agriculture. Evenso, he predicts machine vision systems will be available in approximately three years.
Crow makes a quick side-trip back to Europe to mention the HortiBot, another four-wheeled field rover that already uses machine vision to identify weeds and apply chemicals to them.
Then on to Japan, a country with an aging population that currently only produces 40% of the food it consumes. Despite the shrinking labor pool, the government of Japan hopes to reduce their dependency on foreign imports by increasing the amount grown domestically to 50%. To accomplish this, the Ministry of Agriculture, Forestry and Fisheries has tapped Noboru Noguchi of Hokkaido University to lead a 5-year, $8 million effort to automate all aspects of the cultivation and harvesting of rice, wheat, and soya, and to bring this machinery to market by 2014.
Continuing with the theme of a shrinking labor pool, Crow quotes Eldert (E.J.) van Henten of Wageningen University, The Netherlands, as saying “Work in agriculture is not interesting, prestigious or usually very well paid. It is physically demanding and dirty. People prefer to go to the cities and work in factories or in office jobs. While the population is growing and needs to be fed, a rapidly shrinking number of people are willing to work in agriculture.”
I presume Henten was referring to hired farm laborers rather than to farmers, but even farmers may soon be in short supply. BBC Radio's Farming Today has recently conducted several interviews with people involved in various aspects of agriculture, in which the interviewees have expressed concern that they don't see a new generation of farmers ready to take the places of their elders.
Crow next dives into the economics, beginning with the California raisin industry, which, after being squeezed by a price-crash following a bumper harvest in 2000, began adopting a mechanical harvester adapted from a machine used to harvest ripe grapes for wine. By 2007 almost half of California's raisins were being harvested mechanically. Generally speaking, the use of robots can reduce costs for field operations such as weeding, even after factoring in the cost of machinery and maintenance. One Danish study of organic farming concluded that agribots could reduce the cost of weeding by half.
This article strikes me as being reasonably well-researched, if perhaps a bit simplistic. I see some familiar names. On the other hand, there is no mention of Integrated Pest Management, in which biological control methods are used to reduce the need for chemical pesticides, and for the practice of which autonomous machines could certainly provide assistance. There is also no mention of the significant advantage to be gained, for example in crop breeding, from the generation of detailed, plant-by-plant growth records, nor of the potential for making use of robots to replace monoculture with intense polycultures, including mixtures of deep-rooted perennials and annuals. But comprehensive or not, it's good to see such an article appearing in a publication like New Scientist Magazine, and I'm grateful to Mr. Crow for having gone to the trouble.
