Sunday, October 26, 2014

No-till study illuminates part of the problem space

An extensive review article published on Nature's website, and described on the UC Davis news website, concludes that no-till farming only results in yield increases in dryland areas, and then only when combined with crop rotation and residue retention, and that it results in a yield reduction in moist climates.

While I have no reason to doubt the conclusions of the co-authors, as far as they go, I do have some concerns as to the scope of the comparisons they've made. However, not having read the full article, I can only pose questions and suggest considerations which may offset or even outweigh the modest yield reductions in moist climates, which they've noted.

It's hard to know where to start; this is such a complex subject. As practiced in western countries, no-till usually also means weed suppression by use of herbicides. It may or may not include residue retention, but if the residue is retained it is likely to be in rough form rather than finely chopped, or retained as the dung of the animals that grazed on it after harvest, never as well-distributed as the residue was in the first place. It may or may not include crop rotation, but almost certainly does not include polyculture (also called intercropping), which has become an all too rare practice.

Allow me to back up a bit, and consider an assumption, as expressed by one of the co-authors: "The big challenge for agriculture is that we need to further increase yields but greatly reduce our environmental impacts." Certainly we need to vastly reduce the environmental damage being done by modern agriculture, but just how much do we really need to increase yields. Population growth estimates not taking into account the predictable reduction in fecundity that accompanies prosperity will result in alarmism, but the reality is that what benefits the global economy has to offer the poorest are slowly finding their way to every corner of the planet, and it's reasonable to think that the world population will plateau, if not at ten billion, then perhaps at eleven or twelve billion. Of course, there is hunger now, even starvation, much of it happening in the dryland areas surrounding the Sahara. Yield increases in this region would be particularly helpful, but are complicated by competing uses, as fuel and as animal feed, for the residues which should be left in the fields. Realistically, the bottom line comes down to this: Can we afford to sacrifice long-term fertility for short-term gains in yield?

That question begs another, does the article published in Nature include any long-term studies, by which I mean at least twenty years, preferably longer? Not only does tillage gradually burn through (literally oxidize) soil organic matter, eventually effecting water absorption and retention and nutrient availability, and increasing the energy required for ongoing tillage as the soil becomes denser, but also it takes time for an ecosystem of animals and microbes to develop that can efficiently incorporate crop residues into the soil, particularly in fields that have a long history of routine tillage.

Were any options other than simply leaving residue in the field or grazing considered? Are there any cases of fine-chopping residue during harvest? What about initially removing everything but the stubble and returning it after processing it through animals (as feed), through anaerobic digestion (producing methane gas for fuel), and/or through composting?

Were the costs of production considered? No-till generally involves the cost of herbicide and its application, but tillage is an energy-intensive operation, and over the long term diesel will only become more expensive. If the fuel must be grown, shouldn't the percentage of the overall crop area required to grow it be deducted from the net yields? How does no-till look after performing that calculation?

Nor have we yet seen the full benefits of no-till, because we have yet to develop equipment appropriate to it. Western civilization is so accustomed to tillage that we tend to be blind to assumptions made stemming from a fundamental assumption that tillage is the foundation of agriculture. We see equipment built to perform tillage at work and don't think twice about it. There have been some adaptations – spraying equipment that is only as heavy at it needs to be for that purpose, and oversized tires for heavier equipment – but nearly all of the equipment in use, even in no-till operations, still deals with land as a bulk commodity, measured in acres per hour, rather than at the level of detail required to, for example, selectively harvest one crop while leaving several others, intermingled with it, undisturbed.

Until recently, this could only be accomplished by hand labor, but with the advent of computing using integrated circuits, and its combination with sensory hardware, sophisticated mechanisms, and software to match the problem space (together comprising the field of robotics), the question of whether such work can be mechanized has been transformed into one of how soon. A significant obstacle to this development is cultural, in that we've all but forgotten how to tend land in this manner, and may have to reinvent the practice in order to program the machines. Certainly many in our agricultural colleges and universities will require remedial education.

Saturday, October 18, 2014

Sunday, October 12, 2014

James Gosling of Liquid Robotics at CMU

James Gosling, famed software developer who has spent his last several years working at Liquid Robotics, was recently the featured speaker at a CMU Robotics Institute seminar. My purpose here is not to discuss that talk as a whole, but to focus in on particular issues he discussed which are more generally applicable.

At 52:10, he begins the discussion of fault management, describing, among other things, how LR relies heavily upon features of Java that support continuous operation in the face of problems that would cause software to stop abruptly in other environments.

At 54:30, he discusses communication modes and data prioritization, which is an issue for LR because real-time transmission can cost them as much as $1/kilobyte, for a data rate of ~50 baud.

At 57:46, he briefly discusses security issues, which he says he could have talked about at much greater length.

At 58:43, he mentions Java's write once run anywhere advantage, and how LR makes good use of it in writing and debugging their software.

At 1:05:17, he responds to a comment from the audience regarding inclusion of a basic feature, camera panning, the consequences of various approaches to crafting hardware to support it, and how LR has worked around the problem.

At 1:07:59 he launches into the topic of parts availability, or lack thereof, noting that chips LR would like to acquire are only available as part of circuit boards, or in large lots, which constrains their choices in hardware design.

This last item, the lack of availability of what are, in a volume context, standard parts, is my main motivation for going to the trouble of posting this. It holds back not only the development of robotics, but electronics startups of all sorts, and, to a lesser extent, hobbyists (because in most cases those complete boards are what they need).

Sunday, April 20, 2014

Why robots, revisited

The list of problems is uncomfortably long, and all too familiar...

  • interruption of cycling of biological materials back to land
  • routine tillage accelerating loss of soil carbon
  • soil loss to wind and water
  • reduced ability of remaining soil to absorb and retain water
  • rapid runoff and increased flooding downstream
  • diminished soil fertility and overuse of fertilizers
  • silting and nutrient loading of streams and estuaries
  • overuse of pesticides, herbicides, and fungicides
  • loss of diversity of native flora and fauna
  • loss of diversity in crop species
  • dietary diversity only maintained by long-distance shipping
  • pressure to produce more irrespective of long-term consequences

Most of these problems are addressable by means of better practices...

  • cover crops and mulching
  • crop rotation, polyculture, and perennials
  • recycling of biological materials back to the land
  • maintenance and continual improvement of local crop varieties
  • biological pest controls (free-range chickens, parasitic wasps, etc.)
  • biological and mechanical weed controls
  • minimal cultivation, and that on the contour
  • controlling runoff near the source with terraces and small dams
  • recovering silt from above dams and returning it to the land
  • scaling livestock operations to what available land can provide and absorb
  • hedges, shelter belts, and native-flora waterways
  • providing food and habitat for wildlife

The problem with this set of practices is that, for the most part, they require more attention to detail and don't scale as easily as conventional practice, so they are hard to justify in terms of the farmer's bottom line.

Automation in the form of small robots, operating without constant supervision, and capable of going about farming the right way, could close that gap.

Unfortunately, for most of us, this is a collection of technologies that largely have yet to be created.

On the other hand, the sooner we make it a priority, the sooner it will happen, and the sooner we can get on with the job of healing the planet.

Wednesday, January 22, 2014

stemming the slide of soil degradation

While, in the long run, we should seek to optimize agricultural practice for the improvement of soil health, along with other considerations, in the near term we should be glad for any improvement at all, since the default to be expected from ‘modern’ agriculture is some degree of lost fertility with each passing season.

Traditional practices, like crop rotations including deep-rooted plants like clover, alfalfa, and buckwheat, and like allowing livestock into fields after harvest to browse on the debris left behind, can be enough to tip the scale from degradation to marginal improvement, and can be applied now, without any change in the machinery in use.

We should do what is a matter of differing management choices now, while continuing to work on the technology that will eventually make radically improved techniques possible.

Friday, December 20, 2013

FRE2014 to be held in conjunction with DLG Field Days

Hosted at least in part by the University of Hohenheim, the 2014 Field Robot Event will take place in conjunction with DLG Field Days (brochure, fact sheet), June 17-19, in Strenzfeld, just outside of Bernburg, Germany.