Glass particle waste often ends up in landfills, but perhaps it doesn’t always have to be that way. A new study suggests that mixing ground glass particles with soil can produce a better plant-growing medium than soil alone.
While relatively large pieces of glass can be recycled into more glass of the same color, small pieces of glass of various colors are too small and cumbersome to be efficiently separated for recycling. As a result, large amounts of these small pieces are often simply thrown away, although efforts are underway to change this reality.
Given the fact that both glass and sand are primarily composed of silica, scientists at the University of Texas Rio Grande Valley set out to see if ground glass particles could replace sand in plant growth media. This action would not only divert glass from landfills, but also reduce the need for increasingly scarce mining sand.
The researchers, led by professors Julie Vanegas and Teresa Patricia Feria Arroyo, obtained glass particles from a company that crushes bottles destined for landfills and then rounds the resulting particles to round off the sharp edges. These particles were mixed with commercial potting soil in three sizes, ranging from 100% glass particles to 100% soil.
The scientists then set out to grow cilantro, bell pepper, and jalapeño plants in pots with different growing media under the same greenhouse conditions.
Initially, it was found that when the particles were the size of coarse sand grains, oxygen was best able to reach the roots of the plants and optimum moisture levels were maintained. And, importantly, because the particles rolled, they did not cut off the roots growing around them.
The researchers noted that plants grown in mostly potting soil mixes contained higher levels of nutrients such as nitrogen, phosphorus and potassium, which are essential for plant growth. However, plants grown in mixes containing more than 50% glass particles (by weight) actually grew up They grew faster than those in 100% potting soil and also retained more water. pH levels fell within the same range for all mixes.
The faster growth rate was probably due to the fact that all pots containing 100% soil developed a fungus known to inhibit plant growth. This fungus any The case of pottery containing any amount of glass particles – scientists are currently trying to determine why this is the case.
Whatever the answer, it is hoped that if recycled glass is eventually used on farm soil on a commercial scale, it will reduce the need for problematic fertilisers, pesticides and fungicides.
“I think it’s really important to try to minimize the use of any chemicals that could negatively impact our health,” says chemistry graduate student Andrea Quezada, who presented the team’s findings at the fall meeting of the American Chemical Society. “If we can reduce those and help society by collecting recyclables, then we can give people a better quality of life.”
The effect of glass particles on factors such as yield and taste will be evident during the harvest of the plants.
Source: American Chemical Society