With most of Iowa's 2011 corn and soybean planting completed or on its way to completion, it's time to think about the soil. "Fields at this time are most vulnerable to soil erosion because of degraded crop residue cover during soil preparation by tillage, and the crop canopy is not yet present to protect the soil," says Mahdi Al-Kaisi, Iowa State University Extension soil management specialist.
Even fields with a relatively flat to moderate slope have shown some significant erosion during the past couple week's rain events. "This is especially apparent in areas of the field where grass waterways can be very valuable in reducing soil erosion," he points out. "It is time well spent for farmers to evaluate their conservation measures in fields and take an inventory of fields for proper placement of grass waterways. It is obvious where soil has washed away, you can see where you need to install grass waterways."
Now is the time to check grass waterways, terraces, buffer strips
Likewise, now is a good time to examine existing grass waterways and see whether or not they are working properly. Likewise for terraces. You need to repair damaged grass waterways, buffer strips and terraces or the erosion will just grow worse. Also, the damage to the conservation structure will just increase with rains in the future if the structure isn't functioning properly.
"Springtime rain can come hard and fast as we experienced last week, causing substantial soil erosion," says Al-Kaisi. "By making field observations at this time you can gain some insight on how to manage your field and protect your soil and water quality. The soil profiles in most of Iowa are now filled to capacity with water. Therefore, the amount of rain we receive can exceed the soil storage capacity, especially since plant water use is very low at this time of the year."
Maintenance of grass waterways is essential to maximize the benefits of these conservation practices and the effectiveness of such practices in reducing soil erosion, he adds.
These conservation practices (buffer strips, grass waterways, terraces) are critical for protecting soil quality and sustaining crop productivity. "Also, the relationship between water quality and soil erosion cannot be over-emphasized," notes Al-Kaisi. "Soil erosion and loss of topsoil from your fields can have a huge impact on yield. Using good soil conservation practices can be significant in controlling soil erosion, and improving soil and water quality."