Alternative Farming Cleans up Water

Although the addition of nutrients to soil helps to maximize crop production, fertilizer can leach nutrients, polluting the water supply. A recent study by researchers at the University of Minnesota shows alternative cropping practices may help to protect the environment by reducing high nitrate levels in surface and ground water caused by conventional fertilizer use.
The team of scientists reports their findings in the July-August 2007 issue of the Journal of Environmental Quality.

Nitrogen is one of the most important elements required in agricultural systems for plant and animal production. While treatment with the correct amount of nitrogen-based fertilizer optimizes crop yield and minimizes environmental damage, too much nitrogen can lead to nitrate loss.

Nitrate, a mobile form of nitrogen, escapes via water that percolates through soils. In regions where subsurface drainage is used to promote crop growth, high levels of nitrates are transported to downstream waters. Nitrate contamination of water can contribute to waters becoming hypoxic and stress aquatic life living downstream.

“The challenge facing industry, farmers, agricultural advisors, and others concerned about the environment is to develop efficient cropping systems that maintain economical production levels while minimizing surface and ground water degradation,” says Jeff Strock, lead author of the study.

In search of ways to reduce agricultural pollution, Strock and others measured tile drainage and nitrate losses under conventional and alternative cropping systems over a three-year period in southwest Minnesota. This study was funded by the USDA-CSREES-National Integrated Water Quality Program.

Researchers categorized conventional farming practices as corn-soybean rotations with inorganic fertilizer application and pesticide usage. Alternative farming practices included organic management practices that incorporated rotation of a variety of crops including corn, soybean, oat, alfalfa, buckwheat, and rye with nutrients supplied from legumes and either fresh or composted manure sources. The study found that alternative cropping systems reduced the amount of water lost in tile drainage by 41 percent compared to a conventional corn-soybean rotation. Alternative farming practices also reduced nitrate-nitrogen losses by between 59 and 62 percent in two out of three years.

“Our data suggests that water quantity and quality could be improved by increasing cropping system biodiversity,” says Strock.

Whether in conventional or organic cropping systems, Strock suggests cropping system biodiversity may be adopted as one of several practices to build a sustainable farm management system that is productive, profitable, and environmentally acceptable.

“There are no silver bullets for solving our water quality problems,” says Strock. “Instead, implementing practices such as cropping system biodiversity, along with refined nitrogen management practices, growing perennial crops in a rotation, cover cropping, and other management practices will help prevent nitrate contamination of our lakes and rivers.”

Bookmark http://universeeverything.blogspot.com/ and drop back in sometime.

The New Wildlife Refuge: Golf Courses?

Golf courses are known as centers for human recreation, but if managed properly, they also could be important wildlife sanctuaries, a University of Missouri-Columbia researcher has found.
"There are more than 17,000 golf courses in the United States, and approximately 70 percent of that land is not used for playing," says Ray Semlitsch, Curators' Professor of Biology in the MU College of Arts and Science. "These managed green spaces aren't surrogates for protected land and ecosystems, but they can include suitable habitat for species native to the area. Golf courses could act as nature sanctuaries if managed properly."

Semlitsch, along with Michelle Boone, an assistant professor at Miami University in Ohio and former MU graduate student, and J. Russell Bodie, senior scientist for Audubon International, outlined recommendations that would improve golf course habitats for amphibian populations in a paper published in USGA Turfgrass and Environmental Research Online in January. Their recommendations included buffering aquatic habitats from chemical runoff, surrounding wetland areas with 150 to 300 meters of forest or natural grassland, and creating a diversity of pond types that mimic natural wetlands.

A recent study by Semlitsch, Boone and Cory Mosby, a senior at MU, built on these suggestions. They found that completely drying golf course ponds in the late summer or early fall would benefit amphibian populations and biodiversity.

"It's a hard concept for people to understand, but non-permanent wetlands are more natural than permanent wetlands. Most natural wetlands dry for some periods of time, and the species that live in them are well-adapted for this. The natural drying process benefits amphibians, and it releases nutrients from the soil. Maintaining permanent ponds actually harms biodiversity," Semlitsch said.

In the study, the researchers used two types of ponds -- control reference ponds and ponds located on golf courses -- to monitor populations of American toads, southern leopard frogs and spotted salamanders. They found that the American toads, southern leopard frogs and spotted salamanders survived better in the golf course ponds than in the control ponds, probably because of a reduced number of insect predators. They also found that these species survived better in the absence of overwintered bullfrog tadpoles, which are common to permanent golf course ponds and act as unnatural predators and competitors.

Semlitsch said this shows that greater biodiversity can be achieved by eliminating bullfrog tadpoles. Because bullfrog cycles of metamorphosis take longer to complete (typically 12 months) than the cycles of other amphibians (typically one to four months), the bullfrog tadpoles have advantages in permanent ponds and can grow larger and more powerful, nudging out other species. By drying golf course ponds in the early fall, the tadpoles can be eliminated,

Semlitsch, Boone and Mosby's study will be published later this year in the journal Conservation Biology. It was supported by the United States Golf Association and the National Fish and Wildlife Foundation.

Bookmark http://universeeverything.blogspot.com/ and drop back in sometime.