Food System Input-Output Dynamics

Developing a truly self-sustaining food system on any scale is a large and complicated task. Each food source has its own particular rhythm over the days and season, where the necessary inputs of attention, labour and materials must be provided and the corresponding requirements must be met for a yield to be successfully captured. In this late industrial age failure to complete a cycle is met with disappointment, but one can always head down to the shops to fill in any gaps in the diet. In a post-industrial future the stakes might be much higher, with failure to dance to the rhythm of a major crop leading to potential disaster.

Food sources can be classified by the dynamics of their inputs and outputs on a sliding scale that stretches from continuous to discrete. For example a breed of chickens that lays eggs reliably gives a more continuous output, with lesser variations in production spread across the annual cycle. At the other extreme a meat breed gives their yield all at once in a discrete amount of meat. Individual birds in a flock can be processed one at a time to give a more continuous output though, in contrast to a family that slaughters one cow a year which gives an even more concentrated yield output. These resources can also be classified on a scale that slides from optional to mandatory attention, depending on how flexible they are in their requirements. Resources that are produced continuously are more commonly at the mandatory end of the scale, with eggs needing to be harvested almost every day. Dairy production is even more mandatory, with animals risking illness or a persistent reduction in output if not milked daily. These type of resources demand an inflexible commitment of attention and labour by the farmer. At the other end the optional resources can be harvested at a time of the farmer’s choosing. For a meat chicken it doesn’t make much different if you process them today or next week, though there are usually slow changes in the size and quality of the yield over and extended time. A set of corresponding dynamics exist for the inputs demanded by a particular resource as well. Animals are often more dependent on continuous inputs than plants, with those that produce continuous outputs like laying hens and dairy animals being more sensitive to variations in input quality. Beef cows that can protect and water themselves can be left for weeks in a paddock with minimal attention.

Staple crops follow this classification as well. Grain crops often need to be sowed in a fairly narrow time window, all at once to ensure the crop ripens together for pollination and to make it more difficult for pests to make an impact, similar to how some nut trees mast, producing all their nuts at the same time to overwhelm animals who might eat them. As the grain matures it often needs to be harvested and processed in a very narrow time window, often of just a few days long. Too early and the grain will not filled out, too late and they may shatter or be damaged by moisture. By contrast most tuber staple crops have a longer window for harvest without major losses in crop quality. Some can even be safely stored in the ground to be gradually harvested over months as needed. Once staple crops are harvested though the dynamic reverses. Dried grains can be tapped into intermittently or all at once as needed and the time frame for doing so is fairly long (though not forever, depending on local conditions of temperature and humidity). Tuber crops by contrast tend to have shorter time lines for use after harvest if kept as a live tuber, with sweet potatoes declining significantly by three months and potatoes by six months under typical conditions. Staple crops can be processed into pure starch, which has even better storage properties than whole grains.

Vegetables fall into this classification system as well. Species and strains more suited for commercial production tend to produce all of their crop within a narrow time window, such as a head of broccoli or cabbage. This allows the most expensive input of human labour to be optimised since the whole crop is picked just once. By contrast vegetables more suited for home production tend to produce a more continuous output over a longer period of time, such as kale that can produce leaves for years in some strains. Some crops have very narrow windows for harvest, such as a broccoli head that will burst into inedible flowers if left a couple of days too long. Sturdy cabbage has a longer harvest window, with the lesser risk of splitting. Ripe fruit like tomatoes and immature fruit like eggplants and green beans also have a narrow harvest window for each fruit, demanding constant attention. Failure to pick results in rapid drops in quality plus diversion of the plants resources to resource demanding seeds. Indeterminate tomatoes produce fruit continuously until the plant is exhausted, while determinate types ripen all their fruit at once. If the fruit is intended for preservation then the determinate types are superior for the home garden since they produce enough perishable fruit at once to be worth processing a large batch all at once. Other fruit like capsicums have a longer harvest window since they can be picked at various stages of their lengthy green stage or left to ripen. The best fruit and nut trees that are locally adapted require virtually no inputs beyond establishment, a nice compensation for the ripe fruit usually needing to be harvested within a narrow time window. Often the limiting resource is the attention needed to check the tree at the right time.

When assembling a food system the interplay of these dynamics need to be taken into account. Food resources that demand continuous inputs and produce continuous outputs with low tolerance for variations in each can be very rewarding but place significant demands on the limited time and attention of the farmer. Managing a small dairy herd is probably the most rewarding and demanding of these potential resources, with laying chickens not too far behind. I like to think of my daily routine like one of those old sliding tile puzzles. The more demands I put on my time, the more squares are added to the puzzle, making the job of sliding them to the right position more difficult. Eventually if there is no space left then everything gets stuck and it is impossible to work the puzzle, the point where all my time is taken by non-negotiable activities. My dairy goats are the centre of my time commitment puzzle. I haven’t missed milking them one day in five years and haven’t left the farm for more than a few hours as a result. I had a flock of laying chickens but got rid of them since when combined with the dairy goats there was too little time left in the day for other tasks. I plan to replace them with a small flock of Muscovy ducks for meat and seasonal eggs eventually. The geese need a very small amount of time each day to let them in and out, and if I forget or I am away at night they put themselves to bed, though they need a little more attention for a few weeks while goslings are hatching. At present considerable time is also taken up propagating and planting out trees, which also needs to happen in fairly narrow annual windows in late summer and autumn when soil moisture is high enough to work without irrigation, though if I plant them out today or next week in those seasons it doesn’t make much difference. As time spent establishing trees decreases more time will be spent on the hardy staple crop systems on the creek flats, with smaller amounts of grain crops demanding precise timing but the bulk being root crops with harvest windows stretching many weeks, ideally species that can be left to grow again for another season if I don’t harvest them this year. My vegetables are predominantly varieties that I can harvest when I want them, rather than letting them set my schedule around their needs. Most of the inputs are setting up the beds once a year, with intermittent light weeding when I have time. Fruit gets harvested when it is ripe, with attention being the more limiting resource since I need to see it is nearly ripe and remember to check it again.

Do any job for long enough, without the option of a break, and it will become a chore. The essential quality needed for any activity to be fun is the ever present option of saying no and doing something else instead. The seasonal nature of low input non-commercial food production means that every day is different and there is always time to stop and watch the clouds roll by.

Perishable ripe tomatoes must be picked regularly lest they get lost to rot. This variety is indeterminate, requiring many weeks of attention, so I grow a lot less of this than my all at once fruiting determinate variety used for making sauce.
My most continuous and mandatory food source, the humble dairy goat (snacking on a less time critical storage pumpkin, hence the orange muzzle)

12 thoughts on “Food System Input-Output Dynamics

  1. Another great article! I always enjoy these system focused ones.

    A question about tree cropping.

    “The best fruit and nut trees that are locally adapted require virtually no inputs beyond establishment”

    How do you feel about grafting, intensive pruning, and other forms of high labor input tree management?

    The obvious benefit would be you can produce a yield much earlier, but to me the drawbacks would seem to be 1) my time and effort and 2) the concern that this would make the tree less resilient further down the line. Specifically, pruning a tree to skip its long establishment phase and basically go straight to fruit production seems like it would have long term repercussions to me.

    Just curious if with your tree crops your approach is to just plant and forget or if you take a more active role. I accept that some management is necessary, such as removing lower limbs to inhibit disease spread (as deer and other herbivorous animals naturally would) and possibly pollarding the upper limbs (as the megafauna would have?).

    But provided that I focus on species that will fruit in 5-10 years if left to their own devices, this would seem to me to be just another way people have turned an originally low-input and low-labor system into one requiring large amounts of attention and effort.


    1. I think a chestnut tree is a good example of set and forget in a temperate climate atleast. No pruning or management required besides an initial planting into some sort of uneven ground that mimicks a forest floor. Only way they can die of disease is if you dont harvest all the nuts, which can be easily done by a community nearby if necessary.

      Liked by 1 person

      1. I agree- the best nut trees just require you to turn up and pick them up off the ground. Our huge bunya and black bean are even easier to find. Macadamia are a bit smaller so canopy management to keep undergrowth sparse helps. Chestnuts I grow seem to benefit from being smacked down with a bamboo pole so they don’t hang on the tree too long in the humidity (and so I can pick them up before the rats find them- though that might improve as the trees mature and the yields go up).


    2. I have made a deliberate decision to not pursue grafting as a technique. I did start practicing it and had success but I think the benefits don’t outweigh the drawbacks. Grafted trees do bear earlier, and have more uniform fruit quality, but those are mostly concerns of commercial producers. Ungrafted trees usually live a lot longer than grafts at the other end of the spectrum. And for the scale I am establishing trees on my own grafting simply isnt practical, especially when I just plonk seedlings out and let them live or die with no support. I couldnt justify that harsh treatment for a plant I spent so much time carefully grafting. The only place it might come in would be my establishing persimmon orchard. Ideally I will be culling unproductive trees and replanting seed from the better ones. This produces a mixed age orchard so they dont all reach the end of their life at the same time. The alternative would be grafting the more productive trees onto the rootstocks of the unproductive ones, but then I am signing up for an eternity of managing rootstock regrowth.

      Fukuoka was pretty clear with his experience in pruning fruit trees. Once the trees have been shaped they cannot be let regrow or will become a choking tangle that dies, but seedling trees that are never pruned grow a proper form. I believe a similar thing happens underground to the root system, which once it gets distorted by a pot never quite recovers. I would rather invest in some really good quality mobile ladders, or fruit picking poles, or simply only harvest the fruit from the lower branches. I will probably try pollarding as well on the persimmons as an experiment. With decent genetic diversity in a fruit tree species I might have a chance to select out more naturally dwarf lines as well. For my main production species (persimmon and jaboticaba) I am growing them for vinegar feedstock, so if they get a little bruised on the way to processing it doesnt matter too much as well. With nut trees I will be harvesting varieties that drop onto the ground. The smaller, fiddlier macadamias are in a grove interplanted with Inga so I should be able to keep a closed canopy there, so the undergrowth will be pretty minimal making finding the nuts easier. Bunyas and black beans are so huge they are hard to lose.

      Thanks again for the interesting question!

      Liked by 1 person

      1. Thanks for the in-depth response, it’s appreciated as usual. I’m glad to stimulate discussion.

        It’s good to know that my concerns are valid and that leaving things to their natural state is a valid option. Like many things in modern permaculture, it’s hard to tell the newer suburban fluff from the reliable and time tested methods.


  2. A good article.

    What about planting grafted trees and then getting the seeds of those grafted trees..?

    If for example you have a persimmon orchard of 100 grafted trees. Once they bear fruits you gather the seeds and plant them in between the grafted persimmons. Then once the grafted trees start dying or slowing down in production you cut them down and use the wood as fertilizers (food for fungi) for the seeded trees wich by that time will have grown enough to start producing fruit.
    In this way you can have the quicker fruit production of grafted trees while waiting for the quality seeded trees to produce fruits.


    1. I have planted a fair number of grafted trees (including persimmons) and found them to be severely lacking in both vigor and production. I wanted to tap into some genetics of the old common grafted astringent lines. They were planted out at about 50-100 cm tall and have barely doubled in height in the last four years. A couple have produced one or two fruit (with no seeds, so poor pollination as well). By contrast the trees I grew from seed from local wild trees are now 3-4 m tall and heavy with fruit after 7 years of growth. Even if the grafted trees grew and produced well, they cost $50-70 each, so planting out 100 of them would be hugely expensive. By contrast the seed grown ones cost me less than $10 to plant out 30 trees, just by turning up to check the wild trees at the right time. I now have my own seed being produced from them, which makes planting the other 100 odd trees I want much easier, plus I can start selling seed and seedlings to other people at a very affordable price.


      1. I see, that’s interesting. That is really a significant difference between the grafted and seeded ones.

        I have planted one grafted mango wich was about 1 meter tall when I bought it. I also planted a mango from seed near it.
        The seeded mango is now taller than the grafted mango even tho its much younger.

        Here the avarage grafted fruit tree costs between 4 and 6 dollars so its not as expensive as there. Tho seeds are still slightly cheaper. I also want to plant more trees from seeds.


  3. Problem with growing trees from seed though is the genetic variance in the output. I read recently one of the now common apple varieties was the single useful offspring of 10,000 crosses (think of growing 10,000 trees to maturity only to have one that is useful). Although that being said it is well established that the longer a plant has been grown in one environment (seeding being the purest way) the better its survivability/performance.

    I am curious about your goats as I have not seen an indicator of how large your yard is but gather from context it is on the urban side size wise.
    Are you currently just grazing your goats on pasture? Do you grow any fodder plants for them? I am new to your posts but if goats continually eat from pasture in the same yards they start to accumulate parasites. I am currently in the phase of planning my own farm out and am looking to plant out fodder strips through our pasture. Call it agroforestry or silvopasturing, but either way I think it more closely imitates a goats natural feed and is a much more stable method of feeding livestock.

    Trees shelter the animals and pasture, produce leaf litter which enriches the soil, and wood/woodchips and arent so water demanding as grasses. I am looking to do partially self serve, combined with coppicing/pollarding when they are large enough. Species so far – poplar, paulownia, willow, mulberry, local wattles, tagasaste, pidgeon pea and river tamarind. I hope to test all of these species for palatability, and although some have weedy tendancies, hopefully I can balance access to the goats free ranging on them without killing them or letting them run wild.


    1. I did a post on the economics and details of my goat herd a while back.

      I am definitely raising them on pasture, with virtually no inputs beyond a little mineral powder, licks and seaweed meal occasionally to compensate for our leached out soils. That issue should improve as I get more fodder trees and shrubs established for them. I recall doing an article on goat fodder shrubs as well I think (if not I will do one soon)

      People always bring up the example of how hard it is to produce a good apple variety from seed, but there is so much more to that particular story. Not that long ago apples were commonly produced from seed to plant out large orchards (ala Johnny Appleseed). The reason why this worked is because the apples were grown for pressing into cider, meaning apples with high levels of tannin, or small, or ugly, were fine, and variations in fruit quality averaged out over the orchard. The idea of dessert quality fruit being eaten straight from the tree is a relatively modern idea. And likewise the varieties of apples that have the unusual traits that can be eaten this way (plus are highly responsive to fertiliser/irrigation/hard pruning for rapid harvest/and on top of all that appeal to paying customers)….it is a very long shot. Many of these commercial industrial apple varieties are the lucky product of wide crosses between unrelated lines, which means their genetics is unstable and their own seedlings tend to be highly variable. If you want to breed a productive locally adapted crab apple for making cider or pies then anyone can do it in a single lifetime since those genetic lines are old and fairly stable (plus the tannins tend to make the ripe fruit more pest and disease proof as well). Someone in Tassie should probably be doing this rather than just trying to preserve the dwindling number of grafted heritage varieties.

      My persimmon orchards I am establishing mirror this pattern (no apples here since it is way too warm). I have been gathering seed from a few local wild trees of astringent asian persimmons that were fruiting well despite being completely neglected. The high tannin in the fruit protects them from pests until they are jelly ripe, with a window to harvest them just as they start to color with no netting or protection. I eat a few of the better looking ones when they are ripe, but I am planting them by the hundred for vinegar and alcohol production in the future. My first trial planting of about 30 seedlings just produced wheel barrows of fruit about 7 years from seed. About 1/3 of the trees produced most of the fruit, so as they mature a bit more I will cull out the unproductive ones and those with not so nice fruit. I am also planting an understory of jaboticaba here to fill in the persimmon gaps, also for fermenting, and perfectly productive from seed. Grafted astringent persimmons I planted about the same time at huge expense have born about 1-2 fruit each at 5 years after planting. They don’t even produce seed for increasing my genetic diversity.

      When you look to other species of fruit the issues of variability growing from seed are not as significant, especially if you dont have to meet the many requirements of industrial fruit production. Many citrus, mangos and a few other fruit set polyembryonic seed that are nearly clones of the parent. And less highly bred fruit varieties tend to come more true from seed. And if you are planting seedlings that cost a few cents each you can simply plant 2-4 times as many out as the space can hold mature trees, then cull out the poor performers as maturity arrives.


      1. Yeah your probably not wrong and we have been messing with apple genetics for thousands of years now. That being said I feel too many permaculturalists plant foods that are marginally edible. I mean brag all you want about bumper kale harvests, but id barely wana feed it to the animals =P. Ill be looking at planting a variety of commercial strains of a large variety of fruit and nut trees as a polyculture to attempt to avoid disease which rampage through monocultures. The plan is then to interplant with nitrogen fixing shrubs, berries and other plants and run poultry and foul under some, and pigs under the rest. Ultimately im trying to replicate the natural environment (forest) for each animal domestically while producing more variety then shops offer =( also in this way I will get interesting crosses of high quality apples/other fruits, and excess can go to cider or animal fodder.

        I think that is another benefit to adding shrubs and trees to pastures for grazing, they take up minerals from deeper which poor cultivation techniques have usually robbed from the shallow root zone. With this i feel the animals get a better balance of minerals in their diet and so may require less supplements.

        In your other post you say your running them on 2, 5-arce yards. I always like to play devils advocate and conventional (not always right) wisdom says you should probably be running more numerous, smaller fields and rotating often. There are obviously heaps of successful methods of running goats. But it does appear from the photos shown that the goats have eaten the eyes out of your pastures and weedy pioneers are thriving. Just curious but is this planned? The goats seem to be pushing the yards towards a more bracken/bush filled environment, which may draw you the ire of neighbors and government alike.


  4. Permies who promote plants that are “edible” that they don’t actually eat is one of my bug-bears. A really great example is the malabar chestnut (Pachira species) which are pretty commonly grown in the area. The nuts are “edible” in that you can eat them (they taste like rubbery watery peanuts). Most people eat one or two, then at best simply give seedlings to the next person in the chain of chinese whispers. I did some cursory research into them and they are packed with toxins that damage multiple organ systems, with no way to process them away. In their native habitat they are only regarded as famine food. One day someone is going to eat a large amount of them and get into trouble. Lots of tropical vegetables that grow but don’t thrive here in our hot/humid but too brief late summers also fall into this category.

    Monocultures are great for creating pests and diseases, but once they become established they will cause just about as much trouble for polycultures as well in my experience. It might take a season or two for them to arrive but they turn up sooner or later and never leave. Species need to maintain their natural resistances, and the only way to do that over time is to co-exist with the pests and diseases. Even naturally resistant species often fail when grown outside of their preferred conditions.

    My pastures were once divided into smaller paddocks when I had cows and moved them every week. Cows eat everything down to the ground, and tend to pull out forbs by the roots, so moving them frequently is essential. I started the goats out in the same system but they are very different to cows. They never pull plants out, and only eat the best and most diverse material, and only eat down to about 15 cm from the soil unless starving (a way to avoid parasites). As such the small cells were more trouble than they were worth, especially since the lines needed to be a bit lower than for cows and the goats don’t eat the grass down under the lines like the cows did. Instead a small number of large cells, with understocking of animals, seems to work better. If I keep the numbers low enough I can establish a decent range of fodder shrubs and trees even with periodic direct grazing. In time it will transition to a shrub land then open forest, which suits the goats much better than open pasture, and should support a bigger herd. The current weedy state is just the transition state, also partly caused by a pasture dieback disease killing off most of our grasses a few years ago, and creating a gap mostly filled by shrubby cobblers peg for now. I am actually happy it happened like that since cobblers peg is better feed for the goats than the grasses were, and it much better for establishing trees into. The big goat cells go through an annual cycle as the cobblers pegs grow up to 2 m tall, leaf out and flower, then die back. In a brittle environment I would be in danger of stalling the biology without heavy animal impact like cows do, but in our humid climate the uneaten biomass all gets back into the soil during wet spells.

    I totally agree about mineral cycling from larger plants. I can see particular plants (often legumes) that will only grow close to a patch of gravel, concrete or fill brought in from elsewhere. Our rainy region mountain soils get rapidly depleted of minerals, and a generation of exporting dairy off this land has probably sucked much of the mineral wealth out of it. I also see pasture legumes only occuring downhill from large trees, and the goats get tree branches every day as well to help with their high mineral requirements. Once the property is mostly forested mineral availability should become less of an issue.


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