A new study says that the tiny hairs on plant roots play an important role in reducing soil erosion. Research led by the University of Bristol and published in the journal of Communications Biology provides compelling evidence that when root hairs interact with the surrounding soil they increase soil cohesion by binding soil particles.
Soil erosion is a major problem today and poses a big threat to modern farming. We all know that an increased demand for agriculture has led to forests and natural grasslands being converted to farm fields and pastures.
However, many of the plants grown, such as cotton, coffee, and palm oil significantly increase soil erosion beyond the soil’s ability to maintain and renovate. It can also lead to increased pollution and sedimentation in streams and rivers or, because these areas are often less able to hold onto water, can worsen flooding. This problem is particularly urgent especially because of the increasing human population and changing climate.
Scientists from the Universities of Bristol and Exeter have revealed the crucial function of microscopic roots hairs in binding and reinforcing soil.
Researchers have extensively studied larger-scale root properties such as diameter, length, and surface area to understand their role in preventing soil erosion, the effect of micro-scale properties, such as root hairs is less documented till now.
The research team looked at how wild plants Arabidopsis thaliana, which produced root hairs, compared with an almost identical Arabidopsis with the same root hair structure in reducing soil erosion.
They found that, when planted in sufficient density, plants with root hairs reduced soil loss almost completely whereas identical plants without hairs could not control the flow of erosion.
Three methods were used to explore soil retention by root hairs. First, the samples were placed in a sterile gel, in a petri dish, and then subjected to increasing centrifugal force. The study found that the hairless seedlings were easier to remove from the gel compared to seedlings abundant with root hairs.
Second, the study found that root hairs were also shown to stabilize the plant in the soil, as they increased the force needed to uproot the plant.
Third, in the experimental landscapes laboratory at Exeter, root hairs reduced water erosion to almost zero.
Professor Claire Grierson, one of the study’s lead authors from Bristol’s School of Biological Sciences explained: “These findings could be the key in helping to tackle soil erosion. There are three possible ways root hairs could enhance soil, either the soil might bind directly to root hair surfaces, root hairs might release material that reinforces soil, or root hairs might release material that is processed by microbes into something that can reinforce soil.
Professor Quine, an expert in Earth System Science at the University of Exeter, added: “This exciting, truly interdisciplinary project across biology, maths, engineering, and environmental science has given us invaluable new insights into the influence of microscopic root structures on the macroscopic behavior of soils.
“I was amazed at the difference that root density made in reducing soil erosion to almost zero, when root density was high, whereas soil loss was still significant when roots at the same density had no hairs.
Now the team is working on this topic in greater depth. Let us hope that this leads to something which can help farming and all of us.
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