Measure something
Almost every page on this site ends by telling you to keep a control strip and write down what happened. This page collects that advice in one place, because the evidence gap this library keeps hitting is the one your own field can close.
Why this page exists
Read enough of this library and one instruction repeats on page after page: keep a comparison, and write down what you saw. It is on the grazing page, the hydrogel page, the intercropping page, the pasture-cropping page and the water-retention page, in slightly different words each time. This page gathers it.
The reason it repeats is the same reason the costs page has such a long list of gaps. The measurements that would settle these questions for European farms mostly do not exist. Where a well-resourced search cannot find a number, a farmer with a notebook is not competing with better data — there is no better data.
The clearest illustration is on the water retention page. Europe's largest landscape-retention programme built roughly 100,000 structures, and its own case study says plainly that it "lacks sufficient funding for monitoring and gauging stations to evaluate the success of the catchment restorations." Its successor projects €408 million of spending and a list of benefits nobody will be able to verify. That page's last instruction is the honest conclusion: a staff gauge and a few dip readings put you ahead of a €408 million programme.
The control strip is the whole method
If you take one thing from this page, take this. Leave part of the field doing what it did before, and treat the rest as the trial.
Without it you cannot tell the practice from the weather, and every page here that grades a technique honestly says so in its own terms:
- Rotational grazing: "Keep a set-stocked comparison field at the same stocking rate." Its central caveat is that farms which change their grazing usually change their stock numbers too, so a gain credited to the method may be a gain from carrying fewer animals.
- Hydrogels: "use a control strip and measure yield, not soil moisture alone." A polymer that holds water a root cannot pull out changes your moisture reading and not your harvest.
- Intercropping: sow a sole-crop strip of each component, because that is the only way to work out your own land equivalent ratio rather than borrowing someone else's.
- Ley–arable and pasture cropping: trial the strict version "with a conventional strip beside it, and budget for half the grain."
The strip does not need to be fair to the practice. It needs to be the same field, the same year, the same weather. That is what nothing else can give you.
What to measure, cheapest first
Nothing here needs a subscription. The order is deliberate: each step costs more effort than the one above it, and the first two are nearly free.
| What | How | Why it earns its place |
|---|---|---|
| Rainfall | One gauge, read weekly, written down | Half this library turns on where you sit relative to roughly 700 mm a year. A regional average is not your farm |
| Soil moisture, by feel | A spade and your hand, same spots, same dates | Free, and it catches the thing a 5 km satellite pixel cannot: that pixel covers about 2,500 hectares |
| Pond or tank level | A painted staff gauge | Turns "the pond went down a lot" into a number you can compare between summers |
| Yield, by field or by strip | Whatever the combine or the buyer already tells you | The only measurement that settles whether a practice paid. Most of the arguments on this site are ultimately about this |
| Residual height and recovery days | A stick and a diary, if you graze | The rotational grazing page asks for exactly this, and for the plan to be written down |
| Soil moisture, by probe | Calibrated to your own soil | Last, not first. Precision irrigation warns that "a badly calibrated probe schedules worse than no probe at all" |
Reading what you wrote down
Look at the variance, not the average. This library's recurring finding is that the useful benefit of most of these practices is a smaller gap between a good year and a bad one, rather than a higher mean. A two-year record cannot show you that. A five-year record can.
Do not judge in year two. No-till is the clearest case: expect a dip in the first two years and parity somewhere between three and ten, so "judging it in year two guarantees the wrong answer." The same shape appears on compost, where soil carbon is a five-to-ten-year signal while the cost lands immediately.
Expect the ranking to move. Drought-tolerant varieties re-order from one dry year to the next, and the differences within a single campaign are mostly not statistically significant. One year tells you about that year.
Write down what else changed. Stock numbers, a new drill, a different variety, a wet spring. The confound is almost never the practice; it is everything that changed alongside it.
What this page will not do
It will not give you a cost. We have no European figures for a rain gauge, a staff gauge or a moisture probe, and the costs page explains why we would rather say so than publish American ones. These are all cheap; that is not the same as a price we can stand behind.
There is nowhere here to send your numbers. A public, anonymised record of what European farms actually measured is the obvious next step, and it is the same unbuilt thing as the submission channel on the costs page: it needs a place to put data and a policy about who can see it, which is the owner's decision and not a page's. If you keep records, keep them for yourself first. They are worth having whether or not anyone else ever reads them.