Weather playing usual role in planting

We have seen such a switch from last spring where we were wait­ing for the rain to sub­side so we could get the crops in the ground. Now, one year later, we are wait­ing for the rain to come! This week-end looks to be a scorcher and the National Weather Ser­vice is call­ing for tem­per­a­tures to aver­age 3 to 5 degrees above nor­mal the next two weeks tak­ing us into early June. Nor­mal tem­per­a­tures are highs in the mid to upper 70s and lows in the 50s. They are call­ing for lots of 80s for highs with a few days of 90s and 70s over the next two weeks.

The out­look is for a warmer and drier start to the sum­mer — and scat­tered rain­fall over the next few weeks could stress crops in June or July.

Uneven corn emer­gence: Some replant­ing has been tak­ing place around the county, oth­er­wise the crops seem to be stand­ing fairly well. Some stands of corn seem to be highly vari­able and appear related to past cultural/weather events. In some fields we are see­ing sur­face crust­ing and soil compaction.

What are some of the fac­tors that may con­tribute to poor stands? Accord­ing to Steve Pro­chaska, Exten­sion Agron­omy Field Spe­cial­ist, the use of shal­low tillage tools, work at soil depths of about 4 inches or less, fol­low­ing the year of record rain­fall we had in 2011 and a mild win­ter with­out deep soil freez­ing and thaw­ing may have fur­ther added to exist­ing com­paction. Also, some fields were com­pacted last fall dur­ing har­vest. Finally, add heavy rain­fall events in this spring and you have mul­ti­ple fac­tors that will con­tribute to loss of soil struc­ture with con­comi­tant soil compaction.

Pro­chaska also notes that other pos­si­ble con­tribut­ing fac­tors to the corn stand loss in these fields include:

1. Rota­tion; lim­ited rota­tions with­out wheat or for­age and in some cases mul­ti­ple year soy­beans now fol­lowed by corn.

2. Organic mat­ter (OM) of soils in some areas of the fields was less than 2 per­cent with a cor­re­spond­ing low CEC. Low OM soils may be more prone to crust­ing and compaction.

3. Use of pop-up fer­til­izer applied on corn seed at plant­ing. Apply­ing fer­til­izer to the seed is not a rec­om­mended prac­tice. How­ever, if it is done, for soils with CEC greater than 7, max­i­mum salt index is 8 (lbs of N +K2 0).

4. Her­bi­cide injury. For exam­ple, prod­ucts con­tain­ing cell growth inhibitors may under cer­tain envi­ron­men­tal con­di­tions injure corn seedlings.

5. Insect injury. Var­i­ous insects such as wire­worms, seed corn mag­gots, grubs, etc. have the abil­ity to reduce plant stands.

6. Corn seedling dis­eases caused by var­i­ous pathogens.

7. Mal­func­tion­ing corn planter over seedling depth, fer­til­izer deliv­ery, etc.

The above fac­tors may have been exac­er­bated by very early plant­ing (first week of April). Corn was slow to emerge (in some cases three weeks or more) and was exposed to wet/dry/cold weather events. For more infor­ma­tion, visit etension.entm.purdue.edu/pestcrop/2012index.html.

Rob Leeds is an OSU Exten­sion Edu­ca­tor in Delaware County.

Posted by Rob Leeds on May 25 2012. You can follow any responses to this entry through the RSS Feed. Comments can be made below.