Tuesday, May 10, 2016

Biological Agriculture for Roboticists, Part 2

Not every plant we cultivate for food grows from seed in soil. Some don't grow from seed, either naturally or by our choice, because we want to perpetuate the characteristics of a particularly useful genome.

Vegetative Reproduction
Any plant reproduction that doesn't involve the reshuffling of chromosomes which results from sexual reproduction. Wikipedia has an excellent article on this topic.

Plant Propagation
This is a more general term that includes both reproduction from seed and vegetative reproduction. Again, Wikipedia has this covered.

There are also some plants that naturally don't grow in soil, but here we're mostly interested in cultivation methods not involving soil, except perhaps as an inert granular medium used only for mechanical support.

Generally thought of as a way of producing fish, crustaceans (shrimp, lobsters, crayfish) or gastropods (snails, clams), aquaculture can also be a way of producing food those animals eat, or plant matter for other uses. Everything from suspended phytoplankton to vascular plants anchored on the bottom or floating on the surface can contribute to the biomass available to/from the system. Besides being productive in itself, aquaculture combines well with other practices, because, whether due to the presence of microorganisms or the waste products of animals, the water makes good fertilizer.

Hydroponics & Aeroponics
These are two variations on the theme of growing plants in a nutrient solution without soil, although, in the case of hydroponics, an inert granular medium may be used for mechanical support. Aeroponics is distinguished by the use of mist to keep the roots moist, rather than fluid water, obviating the need for supporting structures sufficiently strong to hold up the mass involved in using large amounts of water, and also avoiding the possibility of anaerobic conditions developing.

Aquaponics is the combination of aquaculture and either hydroponics or aeroponics, where water from aquaculture is used as a fertilizer, and perhaps also plants produced using that water are fed to animals in the aquaculture environment. This cycling of nutrients can result in a highly productive systems which make good use of both space and available light energy.

While aquaponic systems are very good at producing quick-growing leafy greens, like lettuce, and protein from aquatic animals, the cost of infrastructure makes the use of hydroponics or even aeroponics prohibitively expensive for the production of many crops, and for others, like potatoes and peanuts, they are simply unsuitable because the part of the plant we are interested in harvesting grows below the soil surface, or, like wheat, the plants need a dry environment for final ripening and are susceptible to fungal damage if the humidity is too high too late in the growing season. So, we'll be needing soil for awhile yet.

Either way, whether using soil or not, aquaculture can be an integral part of the system.

Also either way, whether using soil or not, whether outdoors, or in polytunnels or permanent greenhouses, or in racks under light from LEDs, or even growing mushrooms in the dark, there's a place for robots, lots of robots, maybe even billions of robots.

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