A round of applause for soil scientists

The Soil Science Society of America (SSSA) applauds what it calls the 'visionary action' taken by U.S. Senator Sherrod Brown and his colleagues who helped usher in legislation to recognize soils as an 'essential' natural resource, placing soil on par with water and air.

On June 23, Senator Brown was joined by co-sponsoring Senators Kent Conrad (D-ND), Charles Grassley (R-IA), Russ Feingold (D-WI), Tom Harkin (D-IA), Ken Salazar (D-CO) and George Voinovich (R-OH) to successfully pass Senate Resolution 440 [*.pdf], which also highlights the 'critical role' soils professionals play in managing soil resources.

This resolution comes at a time when soil is widely undervalued. Soil, and specifically sound soil management, is essential in our continued quest to increase the production of food, feed, fiber, and fuel while maintaining and improving the environment, and mitigating the effects of climate change. Being the essence of all terrestrial life and ecosystem services, we cannot take the soils for granted. Soil is the basis of survival for present and future generations. - Rattan Lal, Ohio State University, SSSA Past President

The Senate resolution passed six months after the European Union's Soil Protection Framework was tabled due to irreconcilable differences among Parliament membership:
energy :: sustainability :: biomass :: bioenergy :: biofuels :: agriculture :: soils :: soil management :: ecosystem services ::

My years growing up working on our family farm taught me the value of hard work and the importance of soil. Often overlooked, healthy soil is vital to maintaining our natural resources and feeding our nation. This resolution is an important first step in cultivating awareness of our nation's soil policies. - U.S. Senator Sherrod Brown

One of the co-sponsors, Senator Ken Salazar, earlier introduced legislation aimed at promoting biochar research (previous post). Biochar, also known as 'agrichar' or 'new terra preta', is seen increasingly as a viable concept to improve and conserve the crucial functions of soils, while generating carbon-negative energy. Salazar's biochar amendment was very ambitious and eventually made it into the new farm bill, but in a strongly watered-down version.

Image: soil scientists analysing soil texture. Credit: SSSA.

References:
Eurekalert: Senate resolution shines spotlight on the importance of soils - July 8, 2008.

U.S. Senate Resolution 440: Recognizing soil as an essential natural resource, and soils professionals as playing a critical role in managing our Nation’s soil resources [*.pdf] - June 23, 2008

Soil Science Society of America.

Biopact: Towards carbon-negative bioenergy: U.S. Senator introduces biochar legislation - October 07, 2007

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Long-running study: some plants can adapt to widespread climate change

While many plant species move to a new location or go extinct as a result of climate change, grasslands clinging to a steep, rocky dale-side in Northern England seem to defy the odds and adapt to long-term changes in temperature and rainfall, according to a new study by scientists from Syracuse University and the University of Sheffield (United Kingdom) published online in the July 7 issue of the Early Edition of the Proceedings of the National Academy of Sciences (PNAS). The experiment on which the study is based is one of the longest-running studies of climate change impacts on natural vegetation and may yield new insights into the effects of global warming on plant ecosystems.

Contemporary wisdom suggests that climate changes cause plants to move or die. However, our study suggests that if the changes in climate occur slowly enough, some plants have the ability to respond, adapt and thrive in their existing location. - Jason Fridley, Assistant professor of biology in The College of Arts and Sciences at SU

The new findings resulted from the analysis of 13 years of data collected at the Buxton Climate Change Impacts Laboratory (BCCIL) in the United Kingdom by Emeritus Professor J. Philip Grime and colleagues at the University of Sheffield. Established in 1989, BCCIL is a field laboratory of grasslands consisting largely of slow-growing herbs and sub-shrubs, many of which are more than 100 years old (map, click to enlarge).

As many as 50 different species of plants per square meter survive the region's hostile conditions by growing in shallow soil and in the nooks and crannies of limestone outcrops. The data analysis was supported by a grant Fridley obtained from the National Science Foundation.

The 13-year experiment at BCCIL involved subjecting 30 small grassland plots to microclimate manipulation. For example, some plots received 20 percent more water than normal during the summer, while other plots were covered with rain shelters in the summer to simulate drought conditions; heating cables were placed under some plots to simulate winter warming.

The grasses in all of the plots were cut to simulate annual sheep grazing. A similar experiment was concurrently conducted on grasslands in Southern England for the first five years. Data collected from the northern and southern sites was the subject of a study published by Grime and colleagues in Science (2000). In the 2000 study, the vegetation in the southern plots was substantially altered by the climate changes, while the Buxton vegetation in the north was virtually unaffected. The southern experiment was dismantled, but Grime continued the experiment on the Buxton plots:
energy :: sustainability :: biomass :: bioenergy :: biodiversity :: extinction :: global warming :: climate change ::

Based on the results of the five-year experiment, we suspected there was something unique happening in the northern grasslands that enabled the plants to resist simulated climate changes. We formed two hypotheses - the plants will eventually be affected, but it will take longer due to chronic nutrient shortage; or the grasslands won't change regardless of how long we manipulate the environment. All of our analysis suggested that the grassland ecosystem is stable, despite the climate manipulations. - Professor Fridley

The new results have yielded more questions than answers; foremost is why are some plants resistant to climate change, while others die, become extinct or migrate to other places? The answers may lie in the nature and behavior of the individual plants within a species.

Individual plants may die or contract, but perhaps they are replaced by those of the same species that are more adapted to the environmental changes. The closer we look, the more complex the systems become. There is actually a lot going on, but we may be missing it because we are looking at a broad spectrum of species instead of what is happening at the level of the individual plants within a species. - Professor Fridley

References:
J. Philip Grime, Jason D. Fridley, Andrew P. Askew, Ken Thompson, John G. Hodgson, and Chris R. Bennett, "Long-term resistance to simulated climate change in an infertile grassland", PNAS, Early Edition July 7, 2008.

University of Sheffield: Buxton Climate Change Impacts Laboratory.

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Iowa State researchers study ground cover to optimize biomass harvest

Ground cover may be one workable method to reduce the effects of erosion that future biomass harvests are predicted to bring. Iowa State University researchers are looking at ways to use ground cover, a living grass planted between the rows of corn, in production farming.

The seemingly limitless national appetite for ethanol has industry and government looking beyond the kernel to the entire corn plant for more fuel. But corn, the source of most of the United States' ethanol, is not limitless, so turning corn stalks and leaves into ethanol is the target of much research.

The U.S. Department of Agriculture projects that by the year 2030, about 20 percent of ethanol will be made by turning corn stalks and leaves, known as corn stover, into fuel. That projection assumes that 75 percent of this corn stover can be harvested for biofuels. Currently, stover is not used to make ethanol.

Farmers now leave corn stover on their corn fields to slow wind and water erosion and re-supply the soil with organic material to ensure future productivity.

According to Ken Moore, Iowa State University agronomy professor, the question is: How do you harvest corn stover in a way that sustains the productivity of the environment for producing future corn? Just as important as the loss of soil through erosion is the loss of organic material that the removal of the stover would bring.

On an average acre of Iowa farmland, there are roughly four tons of stover. Under the expectations laid out by the USDA, three of those tons would be removed and processed into ethanol. That organic matter that won't be returned to the soil to help future crops grow.

We know that soil organic matter is critical, said Jeremy Singer of the USDA's National Soil Tilth Laboratory in Ames. And removing that stover over time is going to decrease the amount of organic matter in the soil. That will lower productivity.

To combat the coming problem, researchers are looking into ways to lower soil erosion while retaining vital organic materials. For Singer, this is a real educational moment. If farmers are going to harvest stover, they have to replace the carbon in the soil, he said.

One promising solution is the idea of planting a ground cover grass between the rows of corn that remains year-round. This grass would not be harvested. This ground cover, or living mulch, will perform all the functions that corn stover currently does:
energy :: sustainability :: biomass :: bioenergy :: biofuels :: cellulosic ethanol :: agronomy :: erosion :: mulch :: ground cover crop ::

Imagine a large flat golf course where you've gone through with a tillage instrument and you've tilled-up every 15 inches. That's what it would look like in farmers' fields, said Moore.

The value you get for the production system is that you could harvest as much of the corn stover as you want without having any problems with conservation. There is a lot of ecological sense to this.

The challenges that the researchers are studying include finding which types of grass will not compete with the corn, what type of corn will withstand the competition, and what sort of agronomic practices will work best.

Corn is not a very competitive species particularly early in the season, said Kendall Lamkey, professor and chair of Iowa State University's agronomy department. Corn doesn't like to be growing with anything else in the field. But later in the growing season, corn can be a little more hospitable to having neighbors share its space.

By the time the corn plant is five inches tall, the kernel number on the corn plant is already determined. That is a measure of the plant's potential yield, said Lamkey. Stress early in the growing season can affect yield greatly, he said.

While this research has just begun, Moore says that this idea is not new. Nature does this all the time, he said. You see prairies that have these complementary mixtures of multiple species that grow and share space. In a way we are sort of simulating the grassland systems that were originally here, but in very simple way.

The grass between the rows will also have other advantages in addition to the ecological benefits. Grasses will help keep weeds down. This will reduce the need for herbicides. Also, grasses, combined with some types of fungi, will help reduce the number of insects that require farmers to spray, said Moore.

These ground cover grasses can also be selected for any number of traits, just like corn can be, said Moore. We are trying to identify the right system of herbicide, strip tillage, and species combination that minimizes competition with corn and maximizes benefits, said Singer.

The one obstacle that researchers must overcome is the effect on corn yield. In the current stages of the research, corn yield suffers because of the competition from the ground cover grasses, said Moore. The goal is produce a ground cover that will not interfere or compete with corn production in any way, he said.

Once that problem is solved, the researchers say that using living mulch as ground cover will be an ecologically sound method of keeping a nutrient-rich soil while harvesting stover in the amounts that the USDA predicts.

Lamkey is optimistic that by the end of the project in two or three more years, they will be able to identify the one or two species of grass that they really need to work with for the living mulch. He is also fairly optimistic that they will be able to identify inbred corn lines that do well in these systems, he said.

That day may not be too far into the future, according to Moore. He envisions a day when smart seed companies are co-developing these packages where they sell ground cover seed and corn hybrids that work in association.

Image: Currently, living mulch negatively impacts yield. The corn on the left is not competing with ground cover. The corn on the right, which has living mulch between the rows, must compete for water and nutrients. Once researchers find the right combination of corn and ground cover, they believe yields will not be impacted, and soil quality will be maintained. Credit: Iowa State University.

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