Extension Communications
3614 Administrative Services Building
Ames, Iowa 50011-3614
(515) 294-9915
6/26/01
Contacts:
Mahdi Al-Kaisi, Extension Agronomy, (515) 294-1923,
malkaisi@iastate.edu
Mark Hanna, Ag and Biosystems Engineering Extension, (515)
294-0468, hmhanna@iastate.edu
Elaine Edwards, Continuing Education and Communication
Servcies, (515) 294-5168, eedwards@iastate.edu
Install and Maintain Terraces for Conservation
AMES, Iowa -- Iowa State University Extension agronomist Mahdi Al-Kaisi and agricultural engineer Mark Hanna suggest that producers check the condition of terraces and identify maintenance requirements. Following excess spring rainfall in many parts of Iowa, now is a good time to check terraces for damage. As a reminder, terraces minimize soil erosion by slowing and reducing the energy of runoff, and by collecting drainage water and directing it underground.
"For those who have sloping fields, terraces are good water and soil management structures. The kind of terraces that can be used -- narrow-based, broad-based or terrace channels -- are flexible and adaptable to the needs of the producer, soil type, erosion potential and equipment considerations," says Al-Kaisi.
Like any conservation practice, once a terrace has been established, it requires hands-on management and maintenance for optimum performance. Properly functioning terraces depend on several things. Hanna says producers need to check the height of the terrace ridge. "Inspect the ridge on older terraces to see whether tillage has disturbed or lowered it. Rehabilitate low spots by adding soil and reestablishing grass cover, and avoid moving soil from the ridge."
Al-Kaisi says that excessive ‘up-slope’ erosion can lead to sediment deposits in the terrace channel and dramatically reduce the terrace’s capacity for water storage. "If sediment deposits are a problem, hire a contractor to clean out the terrace channel. Sediment also can bury a standpipe. If the terrace was designed to allow for some sediment buildup, the standpipe can be extended."
Producers may have seen some slow drainage and standing water this spring. "When that happens, there could be trouble. If, after a normal rainfall, terraces don’t completely drain in two days or less, check the inlet and outlet structures for plugged tile lines. If you cannot find and clear an obstruction, get a contractor’s help in resolving the problem" says Hanna.
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