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)