Sustainable agriculture at the ESA Annu...( Advances in ecology increasingly rev...)

Advances in ecology increasingly reveal that conventional agricultural practices have detrimental effects on the landscape ecology, creating problems for long-term sustainability of crops. In a series of sessions at the Ecological Society of America's Annual Meeting, ecologists will present their ideas on how our agricultural practices can take lessons from natural environments.

The major crops used globally to feed people and livestock wheat, rice, maize and soy are based on an annual system, in which crop plants live one year, are harvested, and are replanted the following year. These systems are notorious, however, for stripping organic nutrients from soils over time.

Perennial systems, on the other hand, contain plants that live longer than one year despite being harvested annually. Many agricultural scientists, including Jerry Glover of The Land Institute, say that perennial crops are the key to creating more sustainable agricultural systems.

"Across agricultural history, we've fundamentally relied on annual grain crops," Glover says. "But at the same time we rely on them, they're degrading the ecosystems they're in, which reduces their productivity."

To compare the long-term sustainability of these two cropping systems, Glover and his colleagues conducted a study on the physical, biological and chemical differences between annual wheat fields and perennial grass fields in Kansas. The fields had each been harvested annually for the past 75 years.

In each test, the researchers found perennial fields to be healthier and more sustainable ecosystems. In the perennial fields, the plants' total root mass was more than seven times that of the annuals, and the roots infiltrated about a foot deeper into the ground. The perennial fields also had higher soil microbe biodiversity and higher levels of dissolved carbon and nitrogen in the
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