food systems

The carbon footprint of urban agriculture

March 22, 2024 By EarthWise Leave a Comment

Urban agriculture – essentially farming within a city – has become increasingly popular worldwide. It is intended to make cities and urban food systems more sustainable. There are social and nutritional benefits to urban agriculture, but its carbon footprint has not been widely studied.

There are high-tech, energy-intensive forms of urban agriculture, such as vertical farms and rooftop greenhouses. But most urban farms are decidedly low-tech such as individual gardens managed by single farmers and community gardens managed by small groups of people.

A comprehensive international study led by the University of Michigan calculated the greenhouse gas emissions associated with the materials and activities of urban farms over their operating lives. The emissions, expressed in the quantity of carbon dioxide equivalents produced per serving of food, were then compared to those of foods raised by conventional agriculture.

On average, food produced through urban agriculture emitted six times higher amounts of CO₂per serving than conventionally grown produce.

The study went on to recommend best practices crucial to making low-tech urban agriculture more carbon-competitive with conventional agriculture. These include making use of infrastructure for more extended periods of time, making use of urban waste, and maximizing social and health benefits.

Urban agriculture offers a variety of social, nutritional, and place-based environmental benefits and has its place in future sustainable cities. It is important to implement it in ways that are most beneficial.

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Study finds that urban agriculture must be carefully planned to have climate benefits

Photo, posted July 27, 2016, courtesy of Sandra Cohen-Rose and Colin Rose via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Pesticide From Beer | Earth Wise

July 23, 2021 By EarthWise Leave a Comment

Researchers from the Neiker Basque Institute for Agricultural Research and Development in Spain have demonstrated that a combination of rapeseed cake and beer bagasse can be used to reduce populations of soil parasites and increase crop yields.

Beer bagasse is spent brewers’ grain – the stuff that is left over after the beer is made. Beer brewing generates substantial amounts of by-products, including large amounts of spent grain. It already has some practical uses, including as a feedstock for biofuel, as a food additive, and it even has some medical uses. But the new research has shown that the bagasse can be the basis for a biodisinfestation treatment to be used in agriculture. The aim is to disinfect soils, protect soil microorganisms, and increase crop yields.

The actual material studied was a mixture of beer bagasse, rapeseed cake, and a generous amount of fresh cow manure. The high nitrogen content of the mixture promotes the activity of beneficial microorganisms in the soil, which helps to break down organic matter and kill off nematodes and other parasites that damage crops.

Nematodes are common parasites that can penetrate plant roots to lay their eggs, which damages the root and prevents the plants from absorbing nutrients effectively. Application of the bagasse-based mixture over 12 months increased crop yields by 15% and boosted healthy soil microbes.

The study demonstrated that agricultural byproducts can be an effective treatment for root-knot nematodes and other soil parasites, increase crop yields, and help promote sustainable food systems to reduce waste from the agricultural industry. The researchers hope to identify other potential organic treatments for tackling soil parasite problems.

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Beer byproduct mixed with manure proves an excellent organic pesticide

Photo, posted July 1, 2011, courtesy of Quinn Dombrowski via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Extreme Heat And Humidity | Earth Wise

June 15, 2020 By EarthWise Leave a Comment

On hot, sticky summer days, one often hears the expression “it’s not the heat, it’s the humidity.” That isn’t just an old saw; it is a recognition of what might be the most underestimated direct, local danger of climate change. Extreme humid heat events represent a major health risk.

There is an index called “wet-bulb temperature” that is calculated from a combination of temperature and humidity data. The reading, which is taken from a thermometer covered in a wet cloth, is related to how muggy it feels and indicates how effectively a person sheds heat by sweating. When the wet-bulb temperature surpasses 95^o Fahrenheit, evaporation of sweat is no longer enough for our bodies to regulate their internal temperature. When people are exposed to these conditions for multiple hours, organ failure and death can result.

Climate models project that combinations of heat and humidity could reach deadly thresholds for anyone spending several hours outdoors by the end of this century.

Dangerous extremes only a few degrees below the human tolerance limits – including in parts of the southwestern and southeastern US – have more than doubled in frequency since 1979. Since then, there have been more than 7,000 occurrences of wet-bulb temperatures above 88^o, 250 above 91^o, and multiple reading above 95^o. Even at lower wet-bulb temperatures around 80^o, people with pre-existing health conditions, the elderly, as well as those performing strenuous outdoor labor and athletic activities, are at high risk.

More research is needed on the factors that generate extreme wet-bulb temperatures as well as the potential impacts on energy, food systems, and human security.

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Dangerous Humid Heat Extremes Occurring Decades Before Expected

Photo, posted April 16, 2012, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Bananas In Danger

October 8, 2019 By EarthWise Leave a Comment

For a few years we have been talking about the precarious position of the global banana crop, which is almost entirely based upon a single cloned cultivar known as the Cavendish banana. The banana you buy in Rome is identical to the one in Rochester. And therein lies the danger: if a fungal blight can kill one banana shrub, it can kill them all.

For decades, a fungal disease known as Panama Disease Tropical Race 4 has been wreaking havoc on banana plantations in the Eastern Hemisphere. Even though it was first identified in Taiwanese soil samples in the early 1990s, the destructive fungus remained confined to Southeast Asia and Australia until it was confirmed in both the Middle East and Africa in 2013. Experts continued to fear its eventual appearance in Latin America, which is the epicenter of the global banana export industry.

In August, Colombian agricultural authorities announced that laboratory tests have positively identified the presence of Tropical Race 4 in the Caribbean coastal region and declared a national state of emergency.

The infection of the banana plant does not produce bananas that are unsafe for humans. What happens is that the infected plants eventually stop bearing fruit.

Cavendish bananas are a prime example of the dangers of growing crops with limited genetic diversity – known as monoculture. It leaves food systems dangerously vulnerable to disease epidemics.

This has happened to the global banana crop before when the predecessor to the Cavendish banana – the Gros Michel – was mostly eradicated by another fungal outbreak. At the moment, there is no ready replacement banana to bail out the industry, but scientists are desperately trying to breed one. In the meantime, the world’s supply of bananas is in real danger.

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The banana is one step closer to disappearing

Photo, posted July 9, 2009, courtesy of Dabin Lambert via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.