Tools for a Changing Climate

Article by Victoria J. Burton, Citizen Science Designer and Facilitator for the GROW Observatory.

Two simple tools — the Flower Power sensor and the GROW Observatory app — are in use around Europe, to help growers and scientists in different but complementary ways. Participants in the GROW Changing Climate Mission are using the Flower Power soil sensors to measure soil moisture, along with temperature and sunlight, in nine GROW Places across Europe. Our GROW Observatory app has lots of useful functions, like an edible plant database with calendar and location functions and well researched information on supporting ecosystems and soils: it is also is a vital part of our changing climate mission. In this mission, the GROW Observatory App helps us to use land survey information to aid interpretation and analysis of satellite data on environmental monitoring.

Soil Moisture

Soil moisture is affected by many different factors, most obviously rainfall and temperature, but also the type of soil, vegetation cover, slope, and aspect of the land. To make sense of the data coming from participant’s Flower Power sensors we need more information about where the sensor is placed — known as metadata (data about data) and this is where the land and land management survey is important.

Canopy cover

Compare a Flower Power sensor under some trees with one in a field of cereals: how might the differences in vegetation influence readings of soil moisture, temperature and light from the soil sensor?

The denser canopy under trees reduces light to the sensor so it will be cooler and shadier. The canopy also intercepts some of the rainfall getting to the soil so moisture levels will rise slower than if there was no canopy present. Soil under a canopy also dries out more slowly after rain due to the lower temperature and sunlight. An area with little canopy dries out faster and wets quicker. This is why we ask you to estimate the canopy covering each sensor so we can control for this in our computer models of soil moisture.

Land use

And here’s where the GROW Observatory app comes in. As we saw above the type of vegetation and canopy cover affects soil moisture but there are other influences of land use. We ask sensor users to assess all visible components of the land surface, for example, trees, shrubs, water bodies, crops and other plants, buildings, roads, greenhouses and many others.

Observing and describing these elements can help us understand how they affect conditions of your site, such as sunshine, moisture, temperature or overall plant growth. For example, a paved area near the sensor may cause rain run to be faster, which in turn may cause sharp increases in soil moisture; it also may retain heat in summer but be colder in winter. For sensor users we ask for five pictures in each cardinal direction (N, E, S, W) and one showing the sensor in the ground. This helps GROW scientists to classify land use and identify any reasons for unexpected readings.

Slope type, position and aspect

Whether land has a slope or a flat plain has major effects on water movement, soil composition and available sunlight. Changes across slopes in a hilly area, or even small changes across a site which can indicate if water will pool or run off, which will influence the availability of nutrients and water to plants. If you look at your country or region, you will likely find that the flatter areas tend to be used for agriculture. Slightly steeper areas might be more suitable for animal pasture and the steepest areas are most often used for forestry. Sometimes growers create flat areas to improve their growing conditions, like many rice terraces in Asia.

Slope aspect is the compass or cardinal direction a slope faces. It affects temperature, light levels, weather and thus processes that influence soil formation (such as erosion, deposition, and rock weathering). All of these factors have a great impact on the growing environment and conditions for plants. You can learn how to measure slope aspect and steepness using simple tools in this video.

Land management

GROW also asks sensor users for information on the land management practices they use around their sensors, for example if they add fertiliser, till or dig, irrigate or mulch. This is because these management practices can influence sensor readings. To illustrate this, take a look at this graph of average soil moisture (blue line) and standard deviation (shaded area) of sensors located in Greece and two individual sensors (orange and green lines).

Notice how the two individual sensors (green and orange lines) have a different pattern to the average moisture reading — there are large spikes in soil moisture so they must be responding to another source of water. This is due to the sensor being close to an irrigation system — keeping records of your land management helps identify any anomalies in your sensor data.

Here is another example showing how different mulches can influence soil moisture readings. Mulches tend to retain moisture in the soil by decreasing the maximum soil temperature and creating a barrier for evaporation of water.

We have seen how soil sensors alone cannot tell us everything — we also need metadata on location, land use, slope and management practices. Together these data can be used to validate data from satellites, and help monitor and predict the effects of climate change. For more on how GROW is validating satellite data read Ground Truthing in GROW Places and for what we have learned so far Our first 1500 soil sensors.

The Land Survey takes 15–20 minutes per sensor and the GROW Observatory app contains all the steps needed. There are also instructions in the Training Manual and training materials on the GROW website.

If you are not taking part in the Changing Climate Mission you can still use the training materials to find out about your growing site, this can help inform you what will grow best and if any management activities e.g. irrigation or mulching may be helpful.

Some of the functions of the GROW Observatory app

The GROW Observatory app for Android or iOS devices is free for anyone to use. The app contains science-based information on practices that help improve your soil and support the wider ecosystem and gives plants that you can grow ‘right now’ in your location.

In all of this, its important to remember that data from GROW Places enable communities to share and use new knowledge and data on growing practices and soil management as a response to our changing climate. And by taking the land survey via the GROW Observatory app, important additional information becomes available for the scientific community regarding the changing climate.