The wettest April on record and historic flooding have kept the majority of Kentucky producers out of fields, delaying planting across the state and prompting producers to consider switching some areas from corn to soybeans.

According to the Kentucky Weekly Crop and Weather Report , 17 percent of the state’s corn crop was planted as of May 1. This is a great deal behind 2010, which had 82 percent of planting completed at this time, and less than the five-year average of 59 percent.

While many of the rivers are projected to crest soon, producers will need to let fields dry out at least a week before planting, with fields along rivers and in creek bottoms likely requiring two weeks. With the current weather situation, it appears many of the state’s producers could just be starting to plant between May 20-27.

“We will see acres being switched to soybeans, but we don’t know how many that will be yet,” said Chad Lee, extension grain crops specialist with the University of Kentucky College of Agriculture .

Corn is historically planted in Kentucky by May 10-15 to reach optimum yield potential with southwestern portions of the state reaching their planting dates first. Corn planted after those dates has an average yield loss of about 1 percent per day. Central Kentucky on-farm data suggests that producers can plant as late as May 20 without seeing any significant yield losses.

High corn prices will likely play an important role in producers’ decisions.

“Corn prices have increased considerably in the last month relative to soybeans,” said Greg Halich, UK extension agricultural economist. “As a consequence, the profitability of corn is quite high compared to soybeans by historical standards. This will extend the corn planting season further into spring than would normally be expected.”

Using current crop prices, fertilizer costs and potential yield losses due to each day of delayed planting, Halich estimated the latest possible dates for producers to plant corn at a profit compared to soybeans in Western Kentucky, east of the Purchase Area. These are May 25 for fair ground, May 29 for good ground and June 2 for the best ground. Producers in the southwest Purchase Area should subtract five days and those in Central Kentucky should add five days.

He added that these dates are flexible and could change if weather conditions don’t improve soon.

“If conditions in the heart of the Corn Belt do not improve quickly, it is likely that the market will respond by further increasing the price of corn relative to soybeans,” Halich said. “Should this occur, the dates will move out further into the planting season, and it would be likely that even on fair ground, corn would still be more profitable than soybeans into early June.”

Producers should contact their crop insurance agent to understand their options related to preventative planting, as this could impact their planting decisions, Halich said. The preventative planting date for corn in Kentucky is May 31.

Planting dates are important and do influence yields, but it is only one factor used in determining yields. Other factors, such as weather and soil conditions, influence yields too and in some cases, have a greater impact than planting dates. For example, only 4 percent of Kentucky’s corn crop was planted by April 19, 2009, and that year yielded the largest corn crop on record, Lee said. In 2008, flooding slowed planting progress across the state, but due to rain in July and August, some of the highest yielding corn in the state was corn planted after May 1. Therefore, even late-planted corn has the potential for good yields.