Soil Crusting, Compaction Plague Many Iowa Fields

Soil Crusting, Compaction Plague Many Iowa Fields

Do a little digging, look at root development, check corn and soybean fields for soil crusting and compaction.

Clear skies and sunshine don't necessarily mean soil conditions are fit for planting. If you question whether areas of a field are dry enough to enter, do a quick test, suggests Nick Benson, corn product specialist at Latham Hi-Tech Seeds. Roll some soil into a ball in your hand. Observe whether the soil breaks apart as you work it.

CROPS HAVE TO LIVE WITH IT: Rain has fallen hard the past couple months, delaying planting and creating soil challenges that remain throughout the growing season. Soil compaction results when heavy equipment travels through wet fields, and soil crusting often results where there isn't crop residue or a cover crop to protect the soil surface from intense rainfall. Crops have to live with these problems all season long.

With the record-setting amount of rainfall received across the state this spring, and a race against time to get the 2013 crop in the ground, it's likely that many seeds were "mudded in." Some easy ways to identify if your field is impacted by soil compaction is by looking for slow water infiltration, water ponding, increased runoff and erosion following an ordinary rain, he says. Nutrient deficiencies in soil can also be attributed to soil compaction. Poor root development and stunted plant growth caused by inadequate nutrients can also help identify an area being affected by soil compaction.

This link will take you to a youtube video featuring Benson actually demonstrating one of the soil condition tests discussed in this article.

Heavy rains and wet soil this spring did more harm than just delay planting

For all of these reasons, Iowa State University research shows compacted fields may experience yield losses of 10% to 30%.  That's why it's important to try and manage the situation as best as possible in future years. Tillage may help water infiltrate the soil rather than sitting on the surface. It also may help increase air movement and improve root growth.

Keep in mind, however, that deep tillage is detrimental to soil organisms like nightcrawlers that need crop residue and to soil fungi that help improve soil structure. To help remediate soils, agronomists suggest you plant a cover crop with vigorous roots.  Manure and compost also can help improve surface soil structure.~~~PAGE_BREAK_HERE~~~

To reduce soil compaction in the future, ISU Extension agronomist Mahdi Al-Kaisi offers these tips:

* Use wider tires, dual tires or tracks

* Minimize tractor weight

* Avoid using oversized equipment

* Minimize tire inflation pressure

* Reduce the number of passes over a field by combining field operations

In a race against time, many fields were planted when soil was too wet

Another concern caused by heavy rainfall this spring is soil crusting. It's especially a concern where there is less crop residue on the soil surface to help absorb the impact of heavy rains. The damaged soil dries hard and cracks, resulting in poor growing conditions and reduced water infiltration.

When the soil surface structure is destroyed, the plant's germination and seedling emergence are both put at considerable risk, says Benson. One common practice to break up soil crust is a rotary hoe. Timing is crucial to avoid seedling damage, so use the rotary when the soil surface is just above field capacity. A quick way to verify this is to take a handful of soil and squeeze lightly. If the soil crumbles easily and leaves a trace of moisture in your hand, you should feel good about hoeing.

Soil compaction, crusting creates problems crops have to live with all season long

If yield loss is a concern in cornfields as the rotary hoe reduces a fraction of the corn stand, keep in mind it will be an insignificant loss (1% to 2%) compared to the potential loss a soil crust can cause, says Benson. It's recommended to operate the rotary hoe at high speeds, 8 to 10 miles per hour, but slow your travel speed if you seem to be experiencing higher stand loss. Benson investigated some fields this spring where the farmer would have been better off to drive a little slower.

While lack of rainfall was the biggest concern facing Midwest farmers during the 2012 growing season, this year too much rain has been the biggest challenge. "The name of the game is maximizing yield, and by taking delicate measures in wet conditions, you are able to minimize the damage to your crop," says Benson. "Pay close attention to the reaction signs your crop is giving you during the 2013 growing season, so you can learn what's going on with your crop and manage those acres differently to avoid such problems in future years."

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