There were too many of us a week ago wishing for some rain. We sure got it. At time of writing here on Saturday afternoon the area received between 1-4" of rain depending on which thunderstorm happened to pass by. Heavy rains are very destructive to soil structure. Big rain drops are like small atomic bombs, which completely shatter soil particles. The result is a tight film of smashed particles across the surface of bare soil and the weight of the standing water adds to the problem. The finer the seed bed, the worse this condition is and many of our fields worked down like powder in April. If your crop was close to emerging, it will still make a stand without too much trouble. If it had just been planted, we will need to keep an eye on crusting problems and be ready to react with some type of crust fighting device.
The other issue for those of you that have corn emerged, with no herbicide down, will be to get that crop sprayed as soon as possible.
I have attched a photo from Aaron's Agronomy Blog showing a 3 leaf corn plant. Research has proven a corn field needs to be weed free by the 3 leaf stage or yield losses can start to accumulate. This is because the weeds, particularly small grasses, compete for the same light as the corn plant. Too many grassy weeds reduce the photosynthetic capability of the young corn plant. The saturated soil conditions will prevent sprayers from moving for several days and more rain is in the forecast. It is another reason why I like some residual herbicide down at planting time. It keeps the crop clean through its early growth stages.