Preparing for the Next Dry Summer: Janet Manning explains why a healthy soil is key to water storage
Far too wet in March… but too dry in the summer… How can anyone best manage the increasingly erratic rainfall we receive as our climate changes? That was the theme of the excellent March Re-B Zoom talk when Janet Manning – the first RHS Garden Water Scientist – shared her professional knowledge. A recording of Janet’s highly informative presentation is given below.
Far too wet in March… but too dry in the summer… How can anyone best manage the increasingly erratic rainfall we receive as our climate changes? That was the theme of the excellent March Re-B Zoom talk when Janet Manning – the first RHS Garden Water Scientist – shared her professional knowledge. A recording of Janet’s highly informative presentation is given below.
In a nutshell, Janet said: we talk a lot about saving water and I’m sure we can all find ways to do that better, but really it’s more about managing water than saving it. If we think about the way the climate is changing, we’re going to see more extremes; we’re going to see longer, hotter, dry spells, we’re also going to see longer spells of heavier rainfall that is going to cause flooding. More surface water too, which in itself can cause as many problems. We need to hang on to some of that excess water when it’s about and then use it during those dry spells.
The most instant and obvious thing that everybody thinks of to save rainfall is water butts. But the natural world doesn’t have water butts. What it has is deep organic, healthy soils. And that’s where we can store lots and lots of water. By adding organic matter to our soils, by not digging the soil and maintaining an open structure it helps the rain infiltrate the soil to recharges the groundwater and be taken up by the plants growing in it. When you want roots to grow in your soil, they need water, but they also need oxygen to respire. And so you’ve got to have that balanced mix of water and oxygen in your soil. And to get that you need those open, air spaces, you need the pores in the soil. And what happens is that when you’ve got healthy soils with lots of invertebrates, earthworms, springtails, wood lice, and many other organisms inhabiting it, they create those little pore structures. The bacteria that live in the exude what I call bacterial poo that’s like a natural swell gel. It creates the sticky sort of glue that helps to glue the crumbs of the soil together, which then opens the soil up. But when you’ve got those air spaces, the soil particles themselves can capture a layer of water. And then you’ve got a really great environment for the roots to grow, that can get all the water they need, and all the oxygen that they need as well.
Among other things Janet went on to talk about was choosing plants that will thrive in the increasingly challenging climate, and the importance of matching their root structure to your soil conditions. There’s far more available on the YouTube video, so do watch the recording of her presentation and discussion, together with her Water Use in Gardens talk (also given below). Reference Water Use in Gardens https://www.rhs.org.uk/science/gardening-in-a-changing-world/water-use-in-gardens |
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Recording of our Zoom Meetup - Gardening for the next dry summer