May 1, 2013

                What a difference a year makes. As of this morning there was estimated only 5% of corn planted in Iowa and Ohio. The 5 year average this time of year is 31%. As we all know the weather has us a little behind the 8-ball this spring. This past Thursday began the start of the real push into spring field work. Anhydrous is being applied throughout the area along with fertilizer and some liquid nitrogen. The long term forecast seems to be favorable for the farmer.

 When we look at the calendar, the typical suitable days for fieldwork for the next week or so, and the optimum Midwest corn planting dates, it is apparent that there will be a stacking up of various field operations this spring. As soon as conditions are favorable there will be a lot of pressure to get spring time anhydrous applications and planting operations moving. When these two tasks are crunched into a short period of time there are greater risks of corn seed and seeding injury from ammonia.

                The question that comes to mind is how soon after anhydrous ammonia application can corn be planted. There are several factors that come to mind to determine this time frame. Some of these include the application depth, soil texture and moisture, rate, distance between knives and direction of application compared to corn rows. Generally it is recommended that growers wait a week after applying ammonia to plant their corn. However, if soil moisture conditions are good, the application depth is 7-9” deep and the anhydrous is applied at an angle to the corn rows, corn can be planted 3-5 days after ammonia application with minimal potential for injury.  Below is interesting graph of the effect of nitrogen rate, application depth and time between ammonia applications and planting, along with some pictures of the damage caused by ammonia burn.

 

Table 1. Effect of applications depth, time of planting, and ammonia toxicity on corn stands. Depth of Application (inches)						Days Delay in Planting after Anhydrous Ammonia Application
0		7		14		0		7		14
200 lbs N/Acre						400 lbs N/Acre
-------------------------------- Plant Population (% of Normal) -------------------------------
4	60		96		100		35		60		90
7	100		100		100		80		100		100
10	100		100		100		100		100		100
(Source: University of Illinois)

 

Corn injury after spring applied anhydrous ammonia

Corn injury after spring applied anhydrous ammonia

 Thanks for reading and don’t forget to stop back next week when we will update you on spring progress.

 

Citation

            http://www.agronext.iastate.edu/soilfertility/photos/mphotosnitrogen.html