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Promoting Biodiversity In Agriculture | Earth Wise

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The organic foods industry is one of the fastest growing agricultural segments in the United States.  According to the Organic Trade Association, U.S. organic sales reached $61.9 billion in 2020, a jump of more than 12% over the previous year. 

Organic food has many benefits.  Organic food is free of antibiotics, growth hormones, and GMOs, and is grown using fewer pesticides.  Organic farming tends to be better for the environment by reducing pollution, conserving water, reducing soil erosion, increasing soil fertility, and using less energy.   And it’s also better for the health of nearby wildlife as well as the people who live close to farms. 

But when it comes to promoting biodiversity in agriculture, is organic farming the only alternative to conventional agriculture? It turns out it’s not – at least according to a new study recently published in the journal Trends in Ecology and Evolution. 

According to an international research team led by the University of Göttingen in Germany, a landscape mosaic of natural habitats and small-scale and diverse cultivated areas is the key to promoting biodiversity on a large scale in both conventional and organic agriculture.

According to the research team, areas cultivated to organic standards have one third more species, but don’t reach the yield level of conventional farming.  This means that more land would need to be cultivated organically in order to produce the same amount of food.  But as larger areas are cultivated, the advantages for biodiversity would disappear.    

Landscapes with small fields, long edges, high crop diversity, and at least 20% near-natural habitats can promote biodiversity significantly more than just organic certification.   

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U.S. Organic Industry Survey 2021

Promoting biodiversity-friendly landscapes – beyond organic farming

Photo, posted August 29, 2019, courtesy of Lance Cheung/USDA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

RNA Modification For Plants | Earth Wise

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We have heard a lot about RNA this past year as messenger RNA vaccine technology has been used for the first time to combat the Covid-19 pandemic.  Now RNA-based technology has shown promise to make major contributions to agriculture.

A group of researchers at the University of Chicago and two Chinese universities have announced that manipulating RNA can allow plants to yield dramatically more crops as well as have better drought resistance.

Adding  gene encoding for a protein called FTO to both rice and potato plants increased their yield by 50% in initial field tests.  The plants were larger, produced longer root systems, and could better tolerate drought conditions.  Further analysis showed that the plants had increased their rate of photosynthesis.

FTO protein erases chemical marks on RNA.  Specifically, it controls a process known as m6A, which is a key modification of RNA.  The FTO erases m6A to reduce some of the signals that tell plants to slow down and reduce growth.  Plants modified with the addition of FTO produced significantly more RNA than control plants.

Experiments with both rice plants and potato plants – which are completely unrelated – demonstrated the same results, indicating that the technique could be broadly applicable.  (The genetic modification is rather simple to make and has worked with every type of plant the researchers have tried it with so far).

These results are just the beginning but demonstrate the potential of a technology that could help address problems of poverty and food insecurity at a global scale as well as responding to climate change.  The world depends on plants for everything from wood, food, and medicine, to flowers and oils. This technique has the potential to dramatically increase the stock material we can get from most plants.

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RNA breakthrough creates crops that can grow 50% more potatoes, rice

Photo, posted September 22, 2014, courtesy of Toshiyuki Imai via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Kenya’s Tana River Basin | Earth Wise

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The Tana River is the longest river and most important waterway in Kenya.  It flows 620 miles from its headwaters in the Abderdare mountain range and Mount Kenya to the Indian Ocean.  The Tana River produces approximately half of the country’s electricity, and supplies Nairobi, the capital of Kenya, with 80% of its water.   

According to the United Nations Environment Programme, eight million people live along the Tana River, where coffee, tea, corn and other crops are grown for export, and fishing and cattle grazing help produce food for large portions of the country’s population. 

But the long-term ability of the river to provide these and other essential services is increasingly under threat due to many factors, including pollution, soil erosion, deforestation, and poor land use practices.   

Climate change is also complicating matters.  According to new research from the University of East Anglia, many species within the Tana River Basin will be unable to survive if global temperatures continue to rise at the current pace.  However, the study, which was recently published in the journal PLOS ONE, also found that many of these species could be saved if the world could meet the climate goals of the Paris Agreement. 

Globally, climate and land use changes are the two biggest threats to biodiversity.  According to researchers, 36% of the Tana River Basin has already been converted to agriculture. 

The research team says stronger commitments on climate change are needed from global leaders.  The climate and biodiversity crises can only be solved with urgent action to reduce global greenhouse gas emissions. 

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The impact of climate change on Kenya’s Tana river basin

Economics of Ecosystem Services of the Tana River Basin

Photo, posted August 19, 2010, courtesy of Luigi Guarino via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Seeds And Climate Change | Earth Wise

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Farmers and agricultural communities around the world are on the frontlines of climate change.  They are among the first to feel the impacts of hotter temperatures as well as more frequent and intense droughts and precipitation. These challenges pose a massive threat to both farmer livelihoods and global food security.

As the planet continues to heat up, many arid regions that already have marginal conditions for agriculture will be increasingly under stress. As a result, researchers from the Massachusetts Institute of Technology and the King Mohammed VI Polytechnic University in Morocco are working on a promising new way to protect seeds from this stress during their crucial germination phase. Their simple and inexpensive process, which was recently described in a paper published in the journal Nature Food, also provides plants with extra nutrition at the same.

The research team has developed a two layer coating for seeds designed for tackling issues related to drought. Drawing inspiration from natural coatings that occur on some seeds like chia seeds, the first layer is designed to protect the seeds from drying out. It provides a gel-like coating that grips any moisture that comes along and surrounds the seed with it.  The second (inner) layer of the coating contains preserved microorganisms called rhizobacteria, as well as some nutrients to help the seeds grow. 

The materials for the coatings are biodegradable, readily-available, and often used in the food industry already.  According to researchers, early tests using common beans have demonstrated encouraging results in Morocco, and more field tests of the seeds are currently underway.

As the climate continues to change, more innovations like this will be necessary for global food security.

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Engineering seeds to resist drought

Photo, posted September 17, 2010, courtesy of Stacy via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Potential Of Artificial Photosynthesis | Earth Wise

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The sun is the primary source of energy on the earth.  Enough solar energy hits the earth in one hour to meet all of human civilization’s energy needs for an entire year.  The two leading forms of renewable energy – photovoltaic solar power and wind power – are ways of making use of the sun’s energy.  Wind power is indirectly provided by the sun; photovoltaic power uses sunlight to generate electricity.

The most efficient use of solar energy on the planet is one perfected by plants millions of years ago:  photosynthesis.  Photosynthesis is a complex sequence of processes by which plants convert sunlight and water into usable energy in the form of glucose.  Plants utilize a combination of pigments, proteins, enzymes, and metals to perform their magic.  If we can develop artificial photosynthesis, it would be a dramatic improvement of humans’ ability to power society cleanly and efficiently.  Whereas photovoltaics capture about 20% of the sun’s energy, photosynthesis stores 60% of the sun’s energy as chemical energy.

Researchers across the globe are working to develop artificial photosynthesis.  A group at Purdue university has been making progress in trying to mimic the ability of leaves to collect light and split water molecules to generate hydrogen. This is a critical step in photosynthesis that is accomplished by protein and pigment complexes known as “photosystems II”.  The Purdue group is experimenting with these proteins and various synthetic catalysts in order to try to develop artificial leaves based on abundant, nontoxic materials. 

It is likely to take a decade or more for artificial photosynthesis technology to become part of our energy system, but its ultimate potential is enormous.

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Soaking up the sun: Artificial photosynthesis promises a clean, sustainable source of energy

Photo, posted June 14, 2007, courtesy of Alex Holyoake via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Greenhouse Gas Emissions From Water Reservoirs | Earth Wise

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A new study by researchers from Washington State University and the University of Quebec at Montreal looked at greenhouse gas emissions from water reservoirs.  It is perhaps surprising to think that water reservoirs are a source of greenhouse gas emissions at all, but that much was already known.  The new study found that those emissions are actually around 29% higher than previously thought.

Overall, the researchers found that the world’s water reservoirs annually produce methane, carbon dioxide, and other greenhouse gases at an amount equivalent to 1.07 billion tons of carbon dioxide.   That is a small fraction of the 36 billion tons produced by fossil fuels and other industrial sources, but it is by no means a negligible amount.   In fact, it is more greenhouse gases than emitted by the entire country of Germany, which is the world’s sixth largest emitter.

Decomposing plant matter near the bottom of reservoirs fuels the production of methane, which is far more potent than carbon dioxide in warming the atmosphere.  This methane degassing accounts for about 40% of emissions from reservoirs.

The study is particularly important because it may be possible to reduce methane emissions from reservoirs by selectively only withdrawing water from near the reservoirs’ surface, which tends to be relatively methane-poor compared to greater depths.  In a related study, reducing withdrawal depth by 10 feet in a Malaysian reservoir reduced methane degassing emissions by 92%.

Human-generated greenhouse gas emissions come from a surprisingly wide range of sources and it is worthwhile studying as many of them as possible in the hope of finding additional ways to reduce the total.

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Greenhouse gas emissions from water reservoirs higher than previously expected

Photo, posted July 22, 2016, courtesy of Iain Merchant via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Vanishing Kelp Forests | Earth Wise

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Bull kelp is the dominant species in offshore kelp forests north of Santa Cruz, California along the west coast of North America.  Bull kelp has similar physical structures to terrestrial plants; it anchors to the ocean floor with root-like structures called holdfasts, and has stem-like structures called stipes from which leaf-like blades stretch out through the water, absorbing nutrients and sunshine.

These giant seaweeds form lush underwater forests in northern California’s coastal waters and have long provided critical habitat for many species like salmon, crabs, and jellyfish.  But now, for much of the California coast, only a few patches of bull kelp remain.

A team from University of California Santa Cruz has studied satellite images of about 200 miles of coastline.  They found that starting in 2014, the area covered by kelp has dropped by more than 95%. 

The die-off was driven in part by an underwater heat wave that depleted nutrients in the water and made it harder for the kelp to grow.  Making matters much worse, populations of purple sea urchins, which eat kelp, have exploded in the region because of overfishing and other reductions in urchin predators such as sea otters.  The sea urchins eat kelp holdfasts, creating so-called urchin barrens where their destructive grazing has decimated kelp forests.

Bull kelp is a species at high risk of becoming endangered.  In coming decades, more marine heatwaves are expected.  These events as well as stronger El Niños will become more common and frequent with climate change.  Between these thermal events and the sea urchins, it will be difficult for kelp forests to survive.

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Ninety-five percent of bull kelp forests have vanished from 200-mile stretch of California coast

Photo, posted October 28, 2015, courtesy of Florian Graner/Green Fire Productions via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Floating Solar In New York’s Capital Region | Earth Wise

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We have previously talked about installing solar arrays on the surface of bodies of water.  The idea is especially attractive in places like Japan where land resources are scarce.  There are several floating solar installations in the UK and the idea is starting to catch on elsewhere as well.

It is quite possible that the largest municipally owned floating solar array may get built in the city of Cohoes in New York’s Capital Region if a project under consideration for federal funding moves forward.

The proposal is for an installation of 8,000 solar panels to cover about 2/3 of the 10-acre Cohoes reservoir.  Cohoes has wanted to erect a solar installation to generate power for its buildings but needed to find suitable vacant land.  The 10-acre manmade reservoir could be an excellent location for a floating solar array.

Cohoes would be the first community in the US to build and own a floating array on a manmade reservoir and could serve as a model for municipalities across the nation.  Such a project makes additional use of land that is already municipal property.  According to the city, the 3.2-megawatt array would generate over 4 million kilowatt hours of electricity per year, saving the city $300-350,000 annually.

Cohoes is seeking $4.59 million in federal funding to support the project and has the support of U.S. Representative Paul Tonko for possible inclusion in the 2022 federal budget. 

Apart from generating electricity, putting solar panels on the surface of a reservoir reduces evaporation, lowers algae growth, and actually improves solar panel performance because of the cooling effect of the water.

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Cohoes reservoir could be a floating solar power pioneer

Photo courtesy of Michael Coghlan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Global Assessment Of Groundwater Wells | Earth Wise

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Water is a fundamental need for every human being on the planet.  Each person requires more than five gallons of clean and safe water a day for drinking, cooking, and keeping clean.

Groundwater wells remain one of the primary sources of drinking water.  In fact, more than half of the world’s population gets its drinking water from groundwater wells.  Groundwater wells also sustain more than 40% of irrigated agriculture.

Researchers from UC Santa Barbara have recently compiled the most comprehensive assessment of groundwater wells to date.  Their research, which was recently published in the journal Science, spanned 40 countries, which collectively account for more than 50% of all groundwater pumping. 

According to the survey’s findings, many wells are at risk of running dry – up to one in five wells, to be exact.  The researchers compared the depths of water tables against well depths. They found that 6% to 20% of the wells in the study were at risk of running dry if water levels continue to decline by just a few meters.

In many areas where groundwater levels are declining, the research team found that new wells are not being drilled deeper to keep pace with the falling water table. As a result, newer wells are just as vulnerable as older wells should groundwater levels continue to decline.  

The researchers hope to expand on this study to include data from China, Iran, and Pakistan, three major users of groundwater from which the researchers could not obtain records.  The researchers also plan to investigate how quickly water tables are dropping and where the trend is accelerating.   

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The largest assessment of global groundwater wells finds many are at risk of drying up

Photo, posted January 20, 2018, courtesy of François Molle via Water Alternatives Photos on Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Harvesting Water From Air | Earth Wise

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Developing new technologies that harvest water from the air is a growing field of research driven by the fact that more and more people live in areas where fresh water is in short supply.  Estimates are that roughly half the world’s population lives in regions with severe freshwater shortages for at least one month each year.

We have previously discussed some of the novel approaches that researchers are taking to enhance water harvesting.  The work at UC Berkeley using metalorganic frameworks is a notable example.

One of the key problems in harvesting water from air is that many droplets that condense from water vapor in the air are too small to be collected and when they cover a surface, they can actually impede further condensation.

University of Texas at Dallas researchers have developed a novel surface that encourages tiny water droplets to move spontaneously into larger droplets.  The droplets actually self-climb along an oil, ramp-shaped meniscus.  The meniscus acts like a bridge along which microdroplets spontaneously climb upward and coalesce with larger water droplets.  They call this the coarsening droplet phenomenon.  It is enabled by a liquid lubricant with a unique hydrophilic nature.  They actually discovered the lubricant’s special properties by accident when in a lubricant test they observed smaller water droplets propel themselves into larger droplets.

Based on experimental data, the coarsening surface enhances the water harvesting rate 200% higher than other techniques.  The team continues to work on ways to use the new lubricant to make sustainable water harvesting systems that are mobile, smaller in size, lower in weight, and less expensive.  If they are successful, they will essentially be able to harvest water anywhere that has air.

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New Physical Phenomenon Aids Harvest of Water from Air

Photo, posted April 26, 2014, courtesy of Toukou Sousui via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Cleaner Water Using Corn | Earth Wise

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Corn is the largest agricultural crop in the U.S., and it is also one of the most wasteful.  About half of the harvest ends up as stover – corn stalks, leaves, husks, and cobs – once the kernels are used for food.

Corn stover has relatively few commercial or industrial uses.  It can be used to produce biofuel, but that is not very energy efficient.  It is sometimes used as a low-quality livestock feed as well.  Mostly, it is just burned if it is used at all.

Researchers at the University of California Riverside have developed an energy-efficient way to make good use of stover by transforming it into activated carbon for use in water treatment.

Activated carbon – often called activated charcoal – is an organic material that is specially treated to contain millions of microscopic pores that make it highly absorbent.  It has many industrial uses, the most common of which is for filtering pollutants out of drinking water.  Most household water filters such as Brita filters as well as the ones built into refrigerators make use of activated carbon.

The Riverside researchers explored methods for producing activated carbon from charred corn stover and found that processing the material with hot compressed water – a process known as hydrothermal carbonization – produced highly absorbent activated carbon with superior properties compared to material produced by slow pyrolysis, where corn stover is charred at increasing temperatures over a long period of time.

According to the researchers, it is important to create approaches that convert waste into high-value materials, fuels, and chemicals in order to create new value streams and eliminate the environmental harm that comes from a so-called “take-make-dispose” economic model.

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Cleaner Water Through Corn

Photo, posted September 15, 2010, courtesy of the United Soybean Board / the Soybean Checkoff via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Potential For Solar Canals In California | Earth Wise

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California’s network of almost 4,000 miles of aqueducts is the world’s largest water conveyance system.  It serves the state’s Central Valley which produces a quarter of America’s food.  About 20% of the nation’s groundwater demand is pumped from Central Valley aquifers.

A recent study by the University of California Santa Cruz and UC Merced has determined that covering these aqueducts with solar panels could be an economically feasible way to advance both renewable energy and water conservation.  California’s aqueducts might more properly be called canals because they are located at ground level.  

The concept of solar canals has been gaining increasing interest around the world as the changing climate leads to more droughts in many regions.  Placing solar panels above the canals can shade them to help prevent water loss through evaporation.  In addition, some types of solar panels can work better situated over canals because the cooler environment improves their operation.  In addition to the increased solar panel output and the water evaporation savings, shade from solar panels could help control the growth of aquatic weeds, which are a costly canal maintenance issue.

Spanning canals with solar panels can be accomplished either by using steel trusses or suspension cables, either of which is more expensive to build than ordinary ground-mounted solar panel supports.  But the research study showed how the benefits of solar canals combine to outweigh the added costs for cable-supported installations.

Apart from the economic benefits of a solar canal system, producing solar energy in the canal system could eliminate the use of 15-20 diesel-powered irrigation pumps, helping to reduce air pollution in a region with some of the nation’s worst air quality.

Solar canals could be a real winner.

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New analysis shows potential for ‘solar canals’ in California

Photo, posted July 23, 2015, courtesy of Lance Cheung / USDA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Rising Seas And Wastewater Leakage | Earth Wise

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Global mean sea level has risen nearly 9 inches since 1880, with over two inches of that over just the last 25 years.  The rising water level is primarily due to two factors:  additional water in the oceans coming from melting glaciers and ice sheets; and the thermal expansion of seawater as it warms.  Climate models estimate that over the course of the century, global sea levels will rise at least a foot even if efforts to reduce greenhouse gas emissions are quite successful and, in the worst case, levels could rise as much as 8 feet.

Faced with this situation, the greatest concerns are, initially, increasing amounts of coastal flooding and erosion and, as things get worse, inundation of coastal regions making many places uninhabitable and creating millions of climate refugees.

Recently, computer modeling studies have focused on an additional imminent problem:  the flooding of coastal wastewater infrastructure, which includes sewer lines and cesspools.

A new study by the University of Hawaii at Manoa is the first to provide direct evidence that tidally driven groundwater inundation of wastewater infrastructure is already occurring in urban Honolulu.  The study shows that higher ocean water levels are leading to wastewater entering storm drains and the coastal ocean.  The result is degradation of coastal water quality and ecological health.

The researchers used chemical tracers to detect groundwater discharge and wastewater present at multiple low-lying areas during spring tides.  During high tides, storm drains become channels for untreated wastewater to flood streets and sidewalks. 

People tend to think of sea-level rise as a future problem, but there are already serious effects going on today that are only going to get worse.

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Sea-level rise drives wastewater leakage to coastal waters

Photo, posted August 23, 2011, courtesy of Eric Tessmer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Scaling Up Green Hydrogen | Earth Wise

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The global hydrogen market generates about $150 billion dollars a year.  The bulk of the market consists of hydrogen used to produce ammonia, refine oil, and produce methanol.  Advocates for hydrogen foresee a $600 billion a year market based on power and industry uses, mobility and transport uses, chemical feedstocks, and construction.  But the problem with expanding the use of hydrogen is that the vast majority of hydrogen in use today is produced from fossil fuels such as natural gas and coal and producing it creates carbon dioxide emissions.

The great hope of the industry is “green hydrogen”- hydrogen produced either without using fossil fuels at all or by capturing and storing the emissions generated. The most likely approach is electrolysis – using electricity to produce hydrogen from water.

Billions of dollars are being invested by both governments and by large oil companies in a race to scale up electrolysis and make it economically attractive.  According to the Hydrogen Council industry lobby group, at least $300 billion is expected to be invested globally over the next decade aimed at developing the green hydrogen that could one day meet almost a fifth of global energy demand.

Many argue that producing green hydrogen with electrolysis is an extremely inefficient way to utilize renewable energy.  Critics of hydrogen-powered vehicles particularly make this argument.   But industrial applications of hydrogen that currently use large amounts of fossil fuels – such as steel manufacturing – may be places where green hydrogen would make a real dent in global emissions.

The race to clean up hydrogen is definitely on.

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The Race to Scale Up Green Hydrogen to Help Solve Some of the World’s Dirtiest Energy Problems

Photo, posted December 16, 2020, courtesy of Sharon Hahn Darlin via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Saving The Giant Sequoia | Earth Wise

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Giant sequoia trees are some of the most remarkable living things on earth.  They can live up to 3,000 years.  The tallest specimens tower over 300 feet, but it is their girth that really sets them apart.  They are usually 20 feet in diameter, and some are up to 35 feet across at the widest.  The largest tree in the world by volume is the General Sherman tree, which has a volume of 52,508 cubic feet. At 2,100 years old, it weighs 2.7 million pounds and is not only the largest living tree, but also the largest living organism by volume on the planet.

Giant sequoias are incredibly hardy.  To have survived thousands of years, the oldest of these trees have endured hungry animals, diseases, fires, snowstorms, El Niño events, years-long droughts, and the efforts of loggers during the 19th and 20th centuries.

In February, unusually high winds knocked down 15 giant sequoias in Yosemite National Park.  While sequoias are amazingly adapted to their narrow range in California’s Western Sierras, it appears as though climate change is altering their habitat faster than the species can migrate or adapt.  Shorter cold seasons have meant more rain instead of snow, leading to floods and mudslides in the winter.  Fires are more likely with less snowpack.  Hotter, drier summers put sequoias under greater stress.

Forest managers work to preserve existing groves through fire mitigation, supplementary water, and careful stewardship of young trees in existing groves.  If these efforts are successful through the ensuing decades, climate change may be just one more thing the sequoias outlasted.  But at least some conservationists are now considering planting a new generation of sequoias in colder, nearby habitats. 

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To Save Giant Sequoia Trees, Maybe It’s Time to Plant Backups

Photo, posted June 8, 2008, courtesy of Joi Ito via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Solar Cell Greenhouses | Earth Wise

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A recent study at North Carolina State University has shown that it can be feasible to use see-through solar panels in greenhouses to generate electricity.  The idea is to use semi-transparent solar panels on greenhouses that allow some of the light to get in for the plants to grow while making the greenhouses energy neutral or even allowing them to generate more power than they use.

The question is how the semi-transparent solar panels might affect greenhouse crops.  To investigate this issue, researchers grew crops of red leaf lettuce from seed to full maturity under a standard set of growing conditions – temperature, water, fertilizer, and CO2 concentration – but varied the light they get. 

A control group was exposed to the full spectrum of white light while three experimental groups were exposed to light through different types of filters that absorbed the particular wavelengths of light that would be absorbed by different types of semitransparent solar cells.

The researchers paid close attention to characteristics of the lettuce that are important to growers, grocers, and consumers:  general appearance, leaf number, leaf size, and weight.  The results were that the lettuce produced using all three kinds of filtered light was essentially identical to that produced in the control group.    Further research is underway looking at how harvesting various wavelengths of light affects biological processes for lettuces, tomatoes, and other crops.

Getting growers to use solar-powered greenhouses would be very difficult if doing so would result in a loss of productivity.  But given these experimental results, it appears as though the decision will boil down to a simple economic argument about whether the investment in new greenhouse technology would be offset by energy production and its resultant savings.

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Study Finds Plants Would Grow Well in Solar Cell Greenhouses

Photo, posted April 8, 2008, courtesy of Brian Boucheron via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Corn Belt Is Losing Topsoil | Earth Wise

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According to a new study published in the Proceedings of the National Academy of Sciences, more than a third of the farmland in the U.S. Corn Belt has completely lost its carbon-rich topsoil due to erosion.   The affected area is nearly 100 million acres and the amount of carbon loss is nearly 2 million tons.

The study, led by scientists at the University of Massachusetts, Amherst, found that the greatest loss of carbon-rich topsoil was on hilltops and ridgelines.  This indicates that tillage – the repeated plowing of fields – was the primary cause of the erosion because loosened soils move downslope.

The loss of topsoil has reduced corn and soybean yields in the Midwest by 6%, resulting in a loss of nearly $3 billion a year for farmers.  In addition, the loosening of the topsoil increases runoff of sediment and nutrients into nearly waterways, worsening water quality.

Previous studies have shown that no-till farming practices can have a significant impact on reducing erosion.  A study published last November found that if farmers shifted entirely to no-till practices, it would reduce soil erosion from U.S. agricultural fields by more than 70%, as well as significantly reducing nutrient and sediment runoff. 

No-till farming is the practice of planting crops without tilling the soil.  Instead, seeds are planted through the remains of previous crops by planters or drills that cut seed furrows, place the seeds, and close the furrow.  Currently less than 15% of farmland in the upper Mississippi River watershed is farmed with no-till practices. 

Even partial changes in tilling practices could produce positive results for topsoil retention and for waterways.

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One-Third of Farmland in the U.S. Corn Belt Has Lost Its Topsoil

Photo, posted September 15, 2010, courtesy of the United Soybean Board / Soybean Checkoff via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Prickly Pear As A Sustainable Crop | Earth Wise

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The fruits and pads of opuntia, better known as prickly pear cactus, find their way into people’s diets in many arid and semi-arid places around the world.  In Mexico, the pads are known as nopales and are used in a variety of dishes.  The pears themselves are used in jams, salads, and juices.

A five-year study by the University of Nevada Reno College of Agriculture, Biotechnology & Natural Resources investigated the prospects for cactus pear to become a major crop like soybeans and corn and to help provide a biofuel source.

As the climate changes, dry areas are going to get dryer and drought issues will increasingly affect traditional crops.

The study looked at the particular opuntia species called the spineless cactus pear and found that it had the highest fruit production while using up to 80% less water than some traditional crops.  Cactus pear can be used for both human consumption and livestock feed.  As a perennial crop, once the fruit and pads are harvested for food, the remaining biomass can be used for biofuel production.

Corn and sugar cane are the most utilized bioenergy crops right now, but these use three to six times more water than cactus pear.  The cactus pear productivity is on par with corn and sugar cane, but not only do they use a fraction of the water, they also have higher heat tolerance.

Over 40% of land area around the world is classified as semi-arid or arid.  There is enormous potential for planting cactus for carbon sequestration.  If nothing else, it makes great sense to grow cactus pear crops in abandoned areas that are marginal and may not be suitable for other crops.

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Study shows cactus pear as drought-tolerant crop for sustainable fuel and food

Photo, posted April 16, 2020, courtesy of Kevin Dooley via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Collapse of Northern California Kelp Forests | Earth Wise

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For thousands of years, thick canopies of kelp formed an underwater forest spanning the coast of Northern California.  Kelp is the cornerstone of a rich subtidal community, providing food and habitat for all sorts of marine creatures.  But in recent years, a shocking transformation has occurred.  Satellite imagery reveals that the area covered by kelp forests off the coast of Northern California has declined by more than 95%.  Only a few small, isolated patches remain.  

In a new study, researchers at the University of California Santa Cruz found that the kelp forest decline was an abrupt collapse as opposed to a gradual decline. 

According to the study, which was recently published in the journal Communications Biology, kelp forests north of San Francisco were resilient to warming events in the past, like El Niños and marine heatwaves. But the decline of a key sea urchin predator – the sunflower sea star – from sea star wasting disease caused the kelp forests’ resiliency to plummet.  Sea urchins are voracious consumers of kelp.     

But it was a series of events – not just the sea urchins – that combined to decimate the Northern California kelp forest.   A marine heatwave that became known as “the blob” developed in 2014 and moved down the West Coast in 2015.  Around the same time, a strong El Niño event developed and brought warmer water up the coast from the south.  The warming ocean waters combined with the ravenous sea urchin population resulted in the dramatic decline of kelp. 

According to researchers, the prospects for a Northern California kelp forest recovery remain poor unless sea urchin predators return to the ecosystem. 

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The collapse of Northern California kelp forests will be hard to reverse

Photo, posted August 13, 2019, courtesy of Sara Hamilton of OSU College of Science via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Solar Energy And Agriculture | Earth Wise

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According to a new study by Oregon State University researchers, co-developing land for both solar voltaic power and agriculture could provide 20% of total electricity generation in the United States with an investment of less than 1% of the annual U.S. budget.

The concept is known as agrivoltaics – using the same land for both growing crops and generating solar energy.  The proponents of agrivoltaics say that it provides more food, more energy, lower water demand, lower carbon emissions, and more prosperous rural communities.

According to the study, wide-scale installation of agrivoltaic systems could lead to an annual reduction of 330,000 tons of carbon dioxide emission in the U.S. – the equivalent of taking 75,000 cars off the road – and the creation of more than 100,000 jobs in rural communities.  All of this could be achieved with minimal effects on crop yields.

The study finds that an area about the size of Maryland would be needed for agrivoltaics to produce 20% of U.S. electricity generation.  That area of 13,000 square miles constitutes about 1% of current U.S. farmland.

The cost of the solar installations would be $1.1 trillion over 35 years and they would pay for themselves from the electricity generated within 17 years.  Installing the arrays would create the equivalent of 117,000 jobs lasting 20 years.

The researchers are going to install a fully functional solar farm on 5 acres of university owned land to demonstrate to the agricultural community and potential future funders how the study’s findings can be applied in real world agricultural systems.

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Combining solar energy and agriculture to mitigate climate change, assist rural communities

Photo, posted October 11, 2011, courtesy of Michael Coghlan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

WAMC Northeast Public Radio

WAMC/Northeast Public Radio is a regional public radio network serving parts of seven northeastern states (more...)