roseweird posted:dank_xiaopeng posted:
really well-run aquaponics schemes have the fishtanks located indoors, which drain into greenhouses that are outside of the main building. free light and heat from the sun means low energy inputs and allows production almost year round for leaf/fruit crops. aquaponics has its downsides (space constraints, pretty tight limits on size of fishtank vs number of crops cultivated, energy costs for pumping) but in small to medium scale operations in dense urban areas they are a novel and useful source for produce. when compared with traditional agriculture, the slightly higher energy cost per unit of production is offset by the comparative proximity to markets.
do you know of any such well-run aquaponics schemes? i've looked up a few and they're Cool but i don't know if i really understand the benefits, other than the aesthetic, of growing seafood and vegetables together in this way. is it really more efficient than just processing waste from fish farms in a centralized fashion, then distributing it as fertilizer to farms and greenhouses? why integrate a fish farm and a greenhouse when you can just put them next to each other?
it's actually fairly energy-intensive to process the fish waste into a form that could be applied directly to conventional crops, moreso than is required to run an aquaponics system. you have to concentrate the wastewater by boiling or passive evaporation; if you just watered crops with the unconcentrated shitwater you'd drown the plants before you'd see much benefit. also, fishtank wastewater contains high levels of ammonia, which is toxic to plants and builds up in the soil if you don't remove it beforehand.
aquaponics systems have an intermediate biofilter between the fish tank and the plant beds that aerates the water and passes it through a substrate filled with alkaline-loving aquatic plants like duckweed, certain types of algae, and bacterial cultures. these plants and bacteria digest the ammonia into nitrite and then to nitrate, which actually increases its usefulness as a hydroponic growth medium.
aquaponics biofilter bed plants like duckweed can then be harvested and fed back to the tilapia, those fish will eat anything. the filtrate is then passed directly to hydroponic grow beds where almost all of the wastes are useable directly by the plants. it seems complicated, but these systems (when they work well) are great in that they really are (mostly) closed loops, other than the input of fish food, fresh water, and heat for the fish tanks in the winter.
the major downside to these systems is that they require a lot of expertise to run correctly, lots of factors need to be constantly fine-tuned and small variables can go out of whack and cause the whole system can fail quickly. that and they're a lot more expensive in terms of equipment investment than composting a bunch of poop and putting it on dirt. like i said, they work best in very dense spaces without access to areas suitable for traditional dirt agriculture. they should be viewed as one of many tools to increase agricultural production, but are by no means the only answer to our problems! revamping our food supply will require diverse techniques and aquaponics is only one of them.
roseweird posted:do you know of any such well-run aquaponics schemes? i've looked up a few and they're Cool but i don't know if i really understand the benefits, other than the aesthetic, of growing seafood and vegetables together in this way. is it really more efficient than just processing waste from fish farms in a centralized fashion, then distributing it as fertilizer to farms and greenhouses? why integrate a fish farm and a greenhouse when you can just put them next to each other?
because engines dont run on fish shit
orchards are one area of industrial agriculture that require a shitload of human labor and are really, really difficult to mechanize. almost all tree crops are pruned and picked by hand. this is a good thing for sustainability advocates, because reducing reliance on petrochemical inputs doesn't require major changes in equipment or infrastructure.
this orchard is bad
and this one is good
the second orchard might look weedy and gross, but it isn't! this orchard uses carefully-tended companion plants to provide nutrients, attract pollinators, and deter pests for the trees. the idea is to mimic natural systems found in forests to build soil fertility. deep-rooted perennial plants like comfreys (the scrubby flowering plant at the base of the tree in the foreground) mine the subsoil for trace elements and store them in their leaves. legumes like clovers, cowpea, or russian olive fix nitrogen in their roots and leaves. several times a year, these companion plants are mowed and used as compost/mulch around each tree. this deters grasses and other weeds that inhibit fruit tree growth.
at the end of the day, you get lots of good fungal and bacterial action in the rich topsoil that builds up around each tree and its companions. companion planting is a surefire way to get most farmers rolling their eyes, but for orchard keepers, they actually make good sense. conventional orchards require tons of petrochemical fertilizers and herbicides to keep trees healthy and weeds down. the resulting monocultures are sensitive to diseases like fungal blight, canker, and scald. these thick companion plantings provide a buffer that slows the spread of diseases, which can be treated individually, reducing reliance on broadcast application of fungicides. another bonus is that they're fairly easy to set up and can be installed in already-established conventional orchards.
daddyholes posted:how does mowing the companion plants and mulching them deter grass
farmer spotted
dank_xiaopeng posted:diseases like fungal blight, canker, and scald
pretty sure those are the headliners for Inferno Fest 2014 bro. some randy applefarmer is pullin yer leg
daddyholes posted:how does mowing the companion plants and mulching them deter grass
sorry, that may not have been clear: the companion plants are pruned down to 4 inches above the ground and the trimmings are layered around each fruit tree, where they are allowed to decompose. the plants are the mulch. they cover up the grass and keep it from spreading too close to the fruit tree the same way normal mulch does, but also makes good compost over time in the bargain. you re-chop the companions several times a year so there's a constant layer of fresher mulch covering the decomposing material below it