Extension Communications
3614 Administrative Services Building
Ames, Iowa 50011-3614
(515) 294-9915
3-20-02
FOR IMMEDIATE RELEASE
Contacts:
Mahdi Al-Kaisi, Agronomy, (515) 294-1923, malkaisi@iastate.edu
Jean McGuire, Continuing Education and Communication Services, (515) 294-7033,
jmcguire@iastate.edu
Field observation -- Key to Planning Spring Field Work
"Planting is a process of observation," says Iowa State University Extension agronomist Mahdi Al-Kaisi. "Weather and soil conditions considerations are among the key management challenges that every producer faces. Soil preparation and planting at the right time are critical elements in good seed germination, which can make a big difference in having a successful crop."
Al-Kaisi says farmers should start with soil moisture. "Soil moisture status can be evaluated by taking a handful of soil from the top six inches to determine if the soil is too wet (or, at 'field capacity'). As a rule of thumb, if squeezing the soil leaves water marks on the palm of your hand or if it forms a ribbon four to five inches long when pushed out between the thumb and index finger, it is too wet to start fieldwork."
Fieldwork performed when the soil is at 'field capacity' can alter soil structure and other soil physical properties such as bulk density, infiltration rate and soil aeration. The end result can be soil compaction and a poor seedbed. Also, changes in the physical properties of soil can cause a significant reduction in surface water infiltration. That leaves more rainfall ending up as runoff instead of moving through the soil profile. More runoff means more potential soil erosion and sediment transport to water bodies.
Crop residue
Spring is also a good time to check crop residue. For most Iowa soils,
stalks, straw, chaff and other plant materials translate directly into
soil erosion control. "Crop residue should be part of every conservation
plan," says Al-Kaisi. "Consensus among soil management experts
is that effective conservation tillage practices leave at least 30 percent
crop residue cover remaining after planting. Every field operation, even
knifing in nitrogen or manure, buries residue and accelerates decomposition.
That can make hitting the 30 percent crop residue target -- especially
after soybeans -- difficult."
Conservation structures
Now is also a good time to conduct inspections of terraces, stand pipes
and waterways. "Conservation structures require hands-on maintenance
for optimum performance," says Al-Kaisi. "Winter can be hard
on conservation structures. Check terrace ridges, standpipes and terrace
channels. Ensure that waterways have retained optimum shape -- wide, shallow,
sod-lined -- to prevent erosion and gullies.
An effective conservation plan depends on planning, observation and maintenance. Make accurate and timely field observations and plan according to current soil conditions. Al-Kaisi suggests making a checklist before heading to the field this spring.
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