Why massive effort needs to be put into growing trees on farms

1 week 3 days ago
India has developed a pioneering national agroforestry policy. Suleman Merchant/Shutterstock

It’s now over 50 years since the world was first warned that resources were being used at an unsustainable rate. It has now been estimated that almost one quarter to one third of the world’s land is degraded to some extent.

Degradation refers to land that’s lost nutrients, or has changed physically, and therefore produces less or supports less life. This is mostly caused by the loss of soil, changes in the quality of the soil, or changes to land cover – like trees being cut down.

About 20% of agricultural land and 40% of forests are degraded. Degradation reduces our capacity to feed a world population that will reach at least 9 billion people by 2050 and it destroys ecosystem services – like the supply of clean water. Also when soil is degraded and trees destroyed, the carbon they contain is released into the atmosphere. Having high levels of carbon in the atmosphere is a major cause of climate change.

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Honey bees, already at risk, face a new threat from a common herbicide

1 week 6 days ago
Foraging bees are exposed to a cocktail of toxic chemicals in the environment. Pixabay

Glyphosate is the world’s most widely used herbicide. Because it’s considered safe for animals, it’s extensively used not only in agriculture, but also for weed control in urban areas and home gardens.

It’s the active ingredient in the controversial weedkiller Roundup, which has been in the news after a recent lawsuit in the US. A jury found that it had caused terminal cancer in a former school groundskeeper who was heavily exposed to the herbicide. The manufacturer, Monsanto, was ordered to pay damages amounting to $289m. The legal battles are continuing.

Glyphosate has been labelled a perfect herbicide. It’s non-selective, killing all plants. And it’s easily translocated in plants and is slow-acting and stable.

From a toxicology point of view, it targets a metabolic pathway involved in manufacturing certain amino acids, the building blocks of proteins. Glyphosate binds to a particular enzyme and inactivates it. This metabolic pathway, called the shikimate pathway, is present in plants but not in animals, so glyphosate is assumed to be harmless to animals. Animals, lacking this enzyme, obtain the amino acids from food.

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There's a new way to "grow" bio-bricks using human urine. Here's how it works.

3 weeks 3 days ago
Thanks to a novel process, human urine can be turned into bio-bricks. Robyn Walker

Recently, researchers from the University of Cape Town in South Africa have “grown” a bio-brick using bacteria and urea found in human urine. The Conversation Africa’s Natasha Joseph asked Dyllon Randall to explain the research and story behind the bio-bricks.

What prompted this project?

Initially, curiosity. Some years ago I read about a US based company called BioMASON that uses the same process we do to produce bio-bricks, but with synthetic urea rather than urine. I was working in the sanitation field and wondered whether real urine could be used instead. Thanks to a one-year feasibility grant from South Africa’s Water Research Commission in 2017, we were able to test the concept – successfully.

So you’re putting what we usually describe as “waste” to good use?

Yes. My research work focuses on rethinking wastewater as a resource. Some of the things we discard – like urine – can actually be converted into useful resources, as this work has shown. This is important if we’re going to achieve a truly sustainable future because we are running out of natural resources at an unprecedented rate.

It’s also about questioning the status quo and trying to improve processes.

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Some smart ideas to make toilets fit for purpose in Africa's cities

3 weeks 3 days ago
Every flush by a typical toilet sends about 6 to 16 litres of fresh water to wastewater treatment centres. lchumpitaz/Shutterstock

About 23% of people living in Sub-Saharan Africa don’t have access to toilets while 31% with toilets use one’s that aren’t connected to a formal sanitation system. This means that more than half the people in sub-Saharan Africa live without proper sanitation – that’s about 570 million people.

One of the problems is that existing toilets aren’t a good fit for parts of sub-Saharan Africa because many areas lack water and there are often no proper plumbing or facilities to treat wastewater.

But there are solutions – toilets that are designed differently. We have come up with some innovative designs overcome the two biggest challenges – excessive use of water, and the fact that urine and faeces aren’t considered as resources.

The designs we suggest have a number of key features. Primarily, they use no water and store and treat urine and faeces separately. They include innovative technologies that reduce water and energy consumption – both vital steps if we’re going to start building smarter, greener cities.

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1 hour 22 minutes ago
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