Louisiana crops struggling early

With persistent low temperatures in the spring coupled with north winds gusting at 35 miles an hour or higher, Louisiana crops are struggling to get established. The cool weather, wind and lack of moisture are the predominant factors slowing the crops.

In central Louisiana and some areas of southwest Louisiana, planting had come to a standstill in early May because of lack of moisture.

Areas in north Louisiana have been somewhat more fortunate when it comes to rainfall. Farmers there are doing some fieldwork, but not at the usual pace. Most of the crops were sand-blasted last week.

Corn shows the most visible signs of stress when conditions are less than favorable for growth. A common problem is the discoloration or purpling of leaves, caused when the crop is under lower-than-normal temperatures and generally not growing very well. Some hybrids demonstrate this characteristic more than others.

The purpling usually is associated with phosphorus deficiency and shows up under very high or low pH and cold or very wet or dry conditions. The plants do not grow rapidly when exhibiting this symptom, but higher temperatures can fix this problem in a couple of days.

The cool weather hampered the growth and development of a large portion of the corn crop that is not showing deficiency symptoms. Corn growth and development are correlated with temperature. In other words, the higher the temperature, the better the growth in general.

According to research conducted by Rick Mascagni a couple of years ago, a Louisiana corn crop needs 3,000 to 3,400 growing degree units to get to black layer or the point where moisture is no longer needed. The accumulation and recording of heat units is a more consistent measurement of maturity under the varying environmental conditions we are experiencing.

The soybean crop is in decent shape but lacking moisture in certain areas. Calls about slugs have been numerous on early-season beans. The solution to the problem is sunshine. The problem is observed more in no-till and reduced-till situations.

The earliest-planted beans in the sentinel plots we are monitoring are all right but not growing very well. The sentinel plot in Rapides Parish, which was planted May 2, is struggling. The sentinel plot in Avoyelles was planted the same day and replanted on March 8 and is at least 4 inches taller than the Rapides plot.

The point of the sentinel plots was to make sure we had something to monitor that was ahead of the rest of the crop. The objective has been achieved.

I estimate that 65 percent of soybean acres in Louisiana will be predominantly Maturity Group 4 varieties. Group 5 varieties and a few Group 6 varieties will be planted in central and southwest Louisiana.

If seed availability this year is an indication of what Group 6 varieties we will have for next year, there will not be many.

The grain sorghum crop is in decent shape. The biggest problem, reported by Jack Baldwin, Extension entomologist, is cutworms in areas of northeast Louisiana.

We need several different things to get back on track. Some need rain, others do not. We all need warmer weather. The saying, “If you don't like the weather in Louisiana, wait 5 minutes,” is not holding up these days.

David Y. Lanclos is the soybean, corn and grain sorghum specialist at LSU AgCenter. e-mail: [email protected]

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