May 9, 2013

                This past week northeast Iowa has gone through all four seasons in 7 days. The way the year has been going it’s not a surprise. From snow last Thursday to 75 degree weather yesterday this spring continues to throw us many curve balls. Take the 2-4” of rain along with 2-4” of snow we have received this past week and we are at another standstill. There has been some fertilizer spread, anhydrous applied and some corn planted but the general consensus is it’s wet. As you can see below the seven day does look fairly dry and with a little luck we can miss the showers on Wednesday be back on track with spring field operations.

                With planting right around the corner there are a few things we should remember about corn germination and emergence. Corn requires approximately 120 to 125 growing degree units (GDUs) from planting to reach emergence, depending on soil temperatures. Corn must absorb 30% of its weight in water to germinate. Seeds can absorb water at temperatures below 50 degrees Fahrenheit, but growth will not occur until soil temperatures are 50 degrees or higher. As temperatures increase, the process required for germination to progress occurs at a faster rate, leading to more rapid emergence. Under ideal conditions, corn will emerge in ten days or less, but with cooler soil temperatures the process may take three weeks or longer.  The formula to calculate GDU’s is simply the daily high temperature plus the daily low temperature minus 50 and then divided by 2.

                Also this week at our Jackson location the construction on the dry fertilizer shed has almost been completed. The construction of the building is complete now they are waiting on the equipment to be installed inside the shed. The liquid fertilizer tank is also nearing completion, the only steps left being to plumb the unload/load system.

               Thanks for reading this week’s blog post. Don’t forget to stop by next week where hopefully we are discussing planting progress in northeast Iowa.

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