Self-watering and self-fertilizing soil sounds like something out of a sci-fi book, but this could soon be a reality thanks to a team of clean energy and microscale engineering professors at the University of Texas at Austin.
As the world’s population grows, it’s important that we develop more efficient and sustainable agricultural practices. Right now, our farming techniques use a lot of water and sometimes too much fertilizer, which is not great for the environment.
These researchers have developed a special type of soil that can actually pull water from the air and slowly release nutrients to plants. Think of it like a super soil that helps plants stay hydrated and fed without needing as much water or fertilizer.
Guihuah Yu, one of the scientists on the team, joined the Standard to share more about how it all works. Listen to the interview above or read the transcript below.
This transcript has been edited lightly for clarity:
Texas Standard: Well, it seems like a catch-22. The planet needs water to grow crops so we can eat, but the demand for water is ever increasing because agriculture uses the majority of it. The way you and your team have approached this problem is interesting: Just change the way we grow crops all together. Explain a little more detail how this soil works.
Guihuah Yu: Sure. So this is solving two critical challenges for sustainable water management: To improve water efficiency, as well as to improve the nutrient take.
What we demonstrated is the special gel – the compose of the two key components. So one of them is trying to do the job of water absorbing. So actually what we use is a calcium chloride embedded into the polymer matrix, through which they can pull the water slowly from the air.
So at night we can imagine that you have a higher rate of humidity, so they can slowly store the water to the soil. But as the sun comes up, you have a little higher temperature. So what the special gel can do is with a temperature increase at daytime, they can slowly release the stored-up water into the plant growth, but also the fertilizer calcium as the nutrient. So they can slowly go into the soil to grow the crops in very challenging conditions, too.
So I understand it’s going to take some more time and research before you can bring these hydrogels into the field. If this continues to show promise, how do you envision this technology being implemented on a large scale?
So that’s a great question. So currently what we demonstrated is more of a proof of concept.
So the mature ingredient incorporated into this super gel, some is coming from more synthetic chemicals, even they are kind of biodegradable – meaning like they are biocompatible and safe to use. But the cost of making some of these ingredients is still relatively high.
So we estimate the current price of our special gel to incorporate into the sandy soil – whatever soil you coat it, and then they can become self-watering and self-irrigation – the cost is still relatively high. So it’s about $10 per per pound.
So we envision to scale up this technology, we wanted to really kind of make these mature ingredients coming from nature. So, for example, using some of these biomass-derived components. So if we can find it in daily life, potentially they can actually keep lowering down the cost.
And of course, when you’re pushing the technology to the practical use, you need to deal with various environments. For example, the temperature, the humidity – some extremely dry, some relatively humid.
So this actually is our next step: to scale up the mature thesis, but also to test in more of the practical setting to really to know when you put into outdoor testing for a longer time and also potentially with much lower cost. So how we can actually work with industry to bring this to the next step is our current focus.
Based on the research you’ve done to address these issues, it’s clear you have a deep commitment to sustainability. What drives you to do this work?
So this really comes from my childhood. So I actually I grew up in a very rural area in a southeastern part of China. And so the area I grew up, it’s actually kind of really short of water sometimes in the very dry the summer. So my parents and also my grandparents, they went very far to get some drinkable water.
So when I grew up actually in these kind of environments, I was actually very aware how like sustainable water management and actually water access to these challenging areas is of profound importance to many areas in the world, especially in many of the developing countries.
And it kind of really came up during my preparation to study the chemistry and the material science to prepare me to be ready to tackle the grand challenges in energy/water accessibility. So that really equipped me with a big motivation to tackle the accessibility challenges.
