Spring N Assessment

Well, here we go again. It seems like it is shaping up to be another wet spring. The last two wet springs have led to N loss, which has left behind other problems that can be corrected if caught soon enough. Simply, added N can be fed to the plant anytime before canopy. After that, N can be dribbled on but rain or irrigation must follow soon after. This conversation leads to a whole bunch of questions. Isn't liquid 28 or 32% N(UAN) costly and time consuming to apply? The short answer is yes, but shortage of N can lead to reduced yield, grain molds, and other problems. The extra cost of adding N far out weighs lack of N fertilizer.

How do we know if N fertilizer has been lost? There are several ways to help make the decision to sidedress. The first is the pre-sidedress nitrogen test(PSNT). This is a soil sample that is collected to a depth of one foot when the corn is between 6 and 12 inches tall. Another way is a calculation that is based on the amount of N applied, yield potential, 5 year yield average, days of soil water saturation, and previous crop. The final determining evaluation is common sense management decision making. If N was applied in the form of UAN more than 2 weeks before an excessive rain, then supplemental N is likely required. If the N was applied as NH3 more than 4 weeks before the excessive rain, then this is a situation to apply more N. Apply 60 to 120 units N per acre.

N fertilization is a moving target on trying to find the right amounts and timing of application. The correct answers depend on the manager, number of acres, availabel labor, crop rotation, ect. It is easier to make recommendations on a case by case basis.

I will start taking morning and evening soil temperatures on April 1. This year I am going to continue on a daily basis(when possible) through mid June. Starting again September 1 until the soil cools for good before winter. Last year the soil temps warmed up nicely in April and I quit because the temps were in the upper 60s. Then May hit and it plumeted, but for the life of me, I can not tell you the soil temperatures in May 2009. I will correct this mistake this spring.

It is about go time for spring work. Make sure all equipment is in working condition and most of all, be safe. Something new for me is a twitter account. Follow me this spring on the current conditions and planting progress at http://twitter.com/pdraisey.

Good night.

Perri

319-929-7851