Organic agriculture boosts biodiversity on farmlands

Does organic farming foster biodiversity? The answer is yes, however, the number of habitats on the land plays an important role alongside the type and intensity of farming practices. These are the findings of an international study that looked at ten regions in Europe and two in Africa. The results has been published in Nature Communications. The study shows that even organic farms have to actively support biodiversity by, for example, conserving different habitats on their holdings.

An international team, including scientists from Technische Universität München (TUM), investigated the contribution of organic farming to supporting farmland biodiversity between 2010 and 2013. Researchers wanted to explore whether organic farms are home to more species than their conventional neighbors. The team used uniform methods across Europe to capture data and analyze it to establish the impact of farming methods and intensity and of landscape features on biodiversity.

"Organic farming is beneficial to the richness of plant and bee species. However, observed benefits concentrate on arable fields," says TUM's Prof. Kurt-Jürgen Hülsbergen. His Chair for Organic Agriculture and Agronomy analyzed 16 Bavarian dairy farms.

The study investigated farms in twelve regions with different production systems. In each region, farms were selected randomly, half of them certified organic for at least five years. In Switzerland, grassland-based cattle farms were studied and in Austria the study looked at arable farms. In Italy and Spain, researchers focused on farms with permanent crops such as wine and olives, and on small-scale subsistence farms in Uganda.

More species because of field boundaries

More species were found in organic arable fields than in non-organic fields. In contrast, there was little difference in grasslands or vineyards. Organic farming benefited the four taxonomic groups of plants, earthworms, spiders and bees -- which were sampled as surrogates for the multitude of creatures living on farmland -- in different ways. In general, more species of plants and bees were found on organic than on non-organic fields, but not more species of spiders and earthworms.

If types of field boundaries such as grass verges or hedges were included in the comparison, the difference between organic and non-organic decreases. "Obviously, most species found in fields on organic farms tend to be concentrated in boundary areas on non-organic farms. There was little difference in the total number of species on the farms," explains Max Kainz, who headed the sub-project at TUM. The occurrence of rare or threatened species did not increase on organic farms, according to Kainz.

Even organic farms need to increase habitats

To sustain farmland biodiversity, which is currently under grave threat, researchers have identified complement organic farming methods with dedicated efforts to conserve habitats. To increase the number of habitats, the authors of the study recommend adding structural elements, such as woods, grass verges and fallow land, to farms. "Surprisingly, viewed across all regions, we did not find a higher number of natural habitats on organic farms than non-organic farms," reports Kainz.

"However, it was clear that habitat diversity is the key to species diversity," adds Prof. Hülsbergen. He continues: "The results of the study underline the importance of maintaining and expanding natural landscape features -- something that the EU's Greening Program has been trying to accomplish." If these additional habitats are different to the rest of the farm, for example hedges in grassland farms or herbaceous strips in arable farms, they have a huge impact on the biodiversity of a farm.

Source: Sciencedaily.com

Packing hundreds of sensors into a single optical fiber for use in harsh environments

By fusing together the concepts of active fiber sensors and high-temperature fiber sensors, a team of researchers at the University of Pittsburgh has created an all-optical high-temperature sensor for gas flow measurements that operates at record-setting temperatures above 800 degrees Celsius.

This technology is expected to find industrial sensing applications in harsh environments ranging from deep geothermal drill cores to the interiors of nuclear reactors to the cold vacuum of space missions, and it may eventually be extended to many others.

The team describes their all-optical approach in a paper published today in The Optical Society's (OSA) journal Optics Letters. They successfully demonstrated simultaneous flow/temperature sensors at 850 C, which is a 200 C improvement on an earlier notable demonstration of MEMS-based sensors by researchers at Oak Ridge National Laboratory.

The basic concept of the new approach involves integrating optical heating elements, optical sensors, an energy delivery cable and a signal cable within a single optical fiber. Optical power delivered by the fiber is used to supply energy to the heating element, while the optical sensor within the same fiber measures the heat transfer from the heating element and transmits it back.

"We call it a 'smart optical fiber sensor powered by in-fiber light'," said Kevin P. Chen, an associate professor and the Paul E. Lego Faculty Fellow in the University of Pittsburg's Department of Electrical and Computer Engineering.

The team's work expands the use of fiber-optic sensors well beyond traditional applications of temperature and strain measurements. "Tapping into the energy carried by the optical fiber enables fiber sensors capable of performing much more sophisticated and multifunctional types of measurements that previously were only achievable using electronic sensors," Chen said.

In microgravity situations, for example, it's difficult to measure the level of liquid hydrogen fuel in tanks because it doesn't settle at the bottom of the tank. It's a challenge that requires the use of many electronic sensors -- a problem Chen initially noticed years ago while visiting NASA, which was the original inspiration to develop a more streamlined and efficient approach.

"For this type of microgravity situation, each sensor requires wires, a.k.a. 'leads,' to deliver a sensing signal, along with a shared ground wire," explained Chen. "So it means that many leads -- often more than 40 -- are necessary to get measurements from the numerous sensors. I couldn't help thinking there must be a better way to do it."

It turned out, there is. The team looked to optical-fiber sensors, which are one of the best sensor technologies for use in harsh environments thanks to their extraordinary multiplexing capabilities and immunity to electromagnetic interference. And they were able to pack many of these sensors into a single fiber to reduce or eliminate the wiring problems associated with having numerous leads involved.

Source: Sciencedaily.com

Can Batteries Replace Power Generators?

When the Long Island Power Authority said last summer that it was going to need new power capacity in the next few years, most people assumed that meant new generating stations or new transmission cables. But of the 16 companies that submitted proposals, one, AES Energy Storage, took an entirely different tack: it proposed batteries.

When all is said and done, batteries are not a source of energy; in fact, they consume it. For every 10 kilowatt-hours put into a battery, only about nine come back out. The battery is a little like a savings account at a bank, but with a negative interest rate. Still, withdrawals are possible at times when they are most useful.

Batteries are a temporary source of energy and power, with the instantaneous ability to meet load and do work. AES is proposing the use of a 400-megawatt battery, with the same output as a medium-size natural gas plant, that can operate for four hours. It would be about 10 times larger than the biggest grid-connected battery system now in service.

AES said the battery would also be a cleaner energy choice. That’s because the alternative would probably be new simple-cycle natural gas plants, which are relatively low in efficiency and have a high output of carbon dioxide and conventional pollutants per kilowatt-hour.

Batteries, on the other hand, could be charged at night using relatively cheap capacity from Long Island’s most efficient generators, combined cycle gas plants. Those use about 7,000 B.T.U.’s of energy per kilowatt-hour, compared with 10,000 or 11,000 for the simple-cycle plants.

Can a battery qualify if the utility wants power?

In fact, in the complicated world of the electric grid, batteries can do some jobs better than generation stations. One is providing a service called spinning reserve. At a power plant, that means spinning a turbine and burning fuel, but not actually making any energy, sitting in standby in case more power is suddenly needed. A battery can sit at the ready without actually spinning or using fuel.

Another is frequency regulation. Alternating current is supposed to change directions 60 times per second, but in reality is always just a little faster or a little slower than that. Plants that provide frequency regulation will add or subtract energy at precise intervals to keep the number of alternations near 60.

Power plants that do this work get extra wear and tear, and modern gas-fired turbines are not as good for that job as old-fashioned steam plants were. Batteries, though, can take up the slack.

John Zahurancik, vice president of operations and deployment at AES, pointed out that getting permission to build batteries is easier than getting the go-ahead to build more power plants. No new permits for air emissions or water consumption would be needed, for example, he said.

The Long Island Power Authority said it was just beginning to evaluate the responses to its request for proposals, which was issued last August. It has not said which submissions met its terms and will be evaluated, and whether proposals for energy storage can compete. Officials there also declined to say whether any of the other bids were submitted by storage companies.

AES already operates an 8-megawatt battery installation in Johnson City, N.Y., near Binghamton and a 12-megawatt system in Chile. It is building a 32-megawatt system in West Virginia adjacent to a 97-megawatt wind farm. Batteries paired with wind farms can smooth out the wind turbines’ highly variable output.

The company’s Long Island proposal is still in an early phase; AES has not, for example, chosen precisely what type of battery it would use.

Source: Nytimes.com