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The plant is the scorecard

Growers come to Steve and say, “I’ve been concentrating on my soil and getting my soil healthy.” “What’s a healthy soil?” he asks, and they tell him what they’re putting on it: “Oh, I’ve got to put this mineral in there.” “No, no, no,” he says. “You’re just balancing the chemistry. That’s not health.”

Then he asks the question that counts: whose point of view are you judging health from, yours or the plant’s? The scorecard for health is your plant. It’s what gives you the yield, and it will tell you how things are going if you ask it the right question: how is it communicating with you?

Balancing isn’t the same as health

A soil test estimates what the soil has on offer. It can’t tell you what the plant actually takes up. Putting a mineral on to balance a soil test is, in Steve’s words, balancing the chemistry. That has its place: structure and chemistry matter, and a very low pH is hard going for any crop. But on its own, it isn’t health.

What happens around the root

“Remember, the most important factor is not the soil itself,” Steve reminds growers. It’s what’s right around the root.

That thin layer, a millimetre or two out from the root, is where the plant and the life in the soil trade. The root pays out sugar. Bacteria and fungi live on it, and hand minerals back, and in most crops the fungi’s fine threads reach far past where the roots can go.

A young root growing down through moist soil, magnified: pale and slightly translucent, fuzzed with fine root hairs, with a smooth rounded tip, among soft red-brown soil crumbs. — The trade happens in the thin layer around the root: sugar out, minerals back. An illustration, simplified.

What you put on changes that layer too. “If you’re going to put nitrates in, you’re going to get hydroxyls out,” Steve says. The root gives them off, the pH right around it goes up, and the trace minerals you’ve just applied don’t release. It’s not about what’s in the soil. It’s what happens around the root. As Steve says, all nitrogen is not equal.

Put a plant in there

If you want your soil to change, Steve says, you’ve got to put a plant in there to change it. “Understand plant health from the plant’s perspective,” as he puts it. “That will drive soil health, because that’s what gives a yield.”

Living roots feed the soil life. A cover crop keeps that going between cash crops, and the next crop’s roots move into the channels and the life the cover crop left behind.

The same ground with young oats and vetch growing through the stubble, fine white roots all through the soil, white fungal threads and small pink nodules on the vetch roots. — If you want your soil to change, put a plant in there to change it. Living roots feed the soil’s life, a cover crop keeps that going between cash crops, and the next crop’s roots move into the channels and the life the cover left behind. An illustration, simplified.

The same ground weeks later: the cover cut and lying as a brown mulch, young beans coming up through it, and their white roots running down beside the cover's old roots. — If you want your soil to change, put a plant in there to change it. Living roots feed the soil’s life, a cover crop keeps that going between cash crops, and the next crop’s roots move into the channels and the life the cover left behind. An illustration, simplified.

Reading it from the plant

Dig up a plant while the crop is growing. Look for plenty of fine roots with clean white tips, and soil that clings to them. Judge it against a good plant of the same crop in the same soil.
Look at the crop itself: its colour, its vigour, how it handles a hot week.
Sap test through the season. The leaves show what the plant is holding, not just what’s in the soil.
Keep your soil tests, and read them alongside the plant.

Soil that clings to the roots is a good sign. It’s held there by the root’s fine hairs and the sugar it pays out, and by the life that feeds on it. A plant that’s struggling often shows it here: few fine roots, tips gone brown, and soil that falls away as you lift it.

A young wheat plant, dug up: green tillers above, and a big mass of fine white roots with soil clinging all along them. — Dig up a plant and read its roots. Plenty of fine roots with clean white tips, and soil that clings to them, is a good sign. A plant that’s struggling often shows few roots, brown tips and soil that falls away. An illustration, simplified.

Another young wheat plant, dug up: thin, pale leaves, and a few short, brown-tipped roots almost bare of soil. — Dig up a plant and read its roots. Plenty of fine roots with clean white tips, and soil that clings to them, is a good sign. A plant that’s struggling often shows few roots, brown tips and soil that falls away. An illustration, simplified.

“The scorecard for health is your plant.”

— Steve, on soil health