Yields and interventions

Expand your understanding of yield

Extending the season of use

Minimum intervention


EXPAND YOUR UNDERSTANDING OF YIELD The harvest from a field of cereals or vegetables is measured by weighing the crop. Thus a hectare of farmland (2.5 acres) can produce 6 tons of wheat or 30 tons of potatoes or 10 tons of lettuce. This is also how we measure our success. High crop yields give us more income and if the cost of growing those crops hasnít also gone up (because of more pesticides, fertilizers or machinery) then the farmer makes a profit. Consider this - what if the farmer is made ill by the constant pressure to produce, the need to maximise profit so that loans can be paid off; what if the soil is losing heart from the constant extraction and the effects of heavy machinery so that the farmer has to work harder, put more in to get the same amount of crop back; and if the wildlife is beginning to disappear as the fields are unsafe for it, disturbed by the noise and activity of farm machinery or through the lack of food because there are no wildflowers or insects; and then suddenly no one wants to buy the produce as the bottom has fallen out of the market for that crop? A gloomy exaggeration perhaps? But it goes to show the pressures and dangers of thinking of yield as our measure of success when it is solely the amount of crop we can harvest. To give you another example Ė will the league tables for schools based on national testing tell you anything other than that the children can sit tests? Does it tell you anything about whether the school is producing well-rounded happy people who can start their adult life reasonably confident in their social and lifeskills and equipped to seek self-education for all of their lives?

Letís go back to the example of farming. There are many more yields to be had and appreciated if we can look to the benefits that are all around us. For instance, shouldnít we appreciate the yield provided by hedgerows around a field? They can positively contribute to the yield of crops grown in the field by harbouring pest predators beneficial to the crop and they can reduce the need for pesticides. They may also have food-for-free in things like blackberries and crab apples. The trees in those hedgerows also have a yield Ė their roots improve water infiltration into the soil and prevent erosion, their leaves can manure the ground with minerals brought up from the subsoil, they act as windbreaks protecting crop growth, and livestock can browse the leaves as an addition to their diet.

 We should also think of a beautiful view as a yield, as well as the scents, colours and shapes that give most of us a liking for the natural world. And if it is people, we should not just define them by the job that they do when instead we should be discovering what other skills they may have, or just appreciating them as good company. The point is that all systems have many yields and we should be alive to these and build on them. We should take our yield in many different ways because there will then be a greater interconnectedness, more satisfaction and less exploitation. Thus we set out to optimise our systems for a range of yields rather than maximise it for one.

EXTENDING THE SEASON OF USE To be able to harvest a crop in one go, farming has driven plant selection to the point where vegetables mature all at the same time rather than naturally being spread out over a useful period. This has carried over into varieties for home growing, causing gluts and then famines. Some people freeze their surpluses, spreading it out over time in that way. But is this a good use of energy? Wouldnít it be better to have something fresh to pick at more times of the year? First, we can make a number of sowings over the season (a succession) so that we have crop maturing at different times. This would work well with salad crops. Then with vegetables like peas, carrots, cabbages or potatoes, we can choose to grow early, mid and late season varieties, which again give us a range of cropping times. We can also spread the season by growing a diversity of product. Donít just grow onions - grow some leeks, shallots, and garlic as well. Also grow some perennial onions such chives, welsh and tree onions. And, as a general rule, a bad year for one crop is quite often a good year for another Ė thus a cold wet spring is bad for pears but is often good for raspberries. Thus not only does diversity spread our season, it also gives us security of yield. Crops can be stored to increase their season of use. Root crops were traditionally stored in clamps under straw and earth, or in cool root stores on the north sides of houses. These root crops, potatoes, carrots, swedes, onions, all have a period of dormancy before they sweep back into growth the next year. So if we keep them in the right conditions, we can use them from store over the winter, keeping them fresh and unspoilt by the harshness of cold and rain. Bottling and preserving can spread yield as well, as can simple methods of drying. These examples of extending yields are based on food, but the ideas can be applied to all the resources we can harvest Ė think of rainwater.


MINIMUM INTERVENTION Why try and fix something if it isnít broken? We sometimes have this irresistible urge to take things apart, or completely clear away or demolish things just to give us a clean sheet to work with. Is it worth the effort to level off your garden when the mounds and troughs might make interesting changes of level and planting habitat? Would we drain a marsh or bog when we can now see some advantage in maintaining the species that thrive in that habitat?

We must avoid falling down the spiral of intervention or even starting at the bottom because we can cause more damage than the good that we set out to do. And, like the example of the farmer above, we might find ourselves in the downward spiral of putting in more and more while only getting back the same or a reducing yield.

Mark Fisher - Permaculture Design course handout notes

www.self-willed-land.org.uk   mark.fisher@self-willed-land.org.uk