“I’m just not sure my manure nutrients are giving me the best results on my corn crop, what’s the problem?” I’ve had this question from several farmers lately, so let’s start down the list and see what components may be missing that can be caught up this spring:
- Do you have a manure sample you are comfortable with? A manure storage that has little bedding and is agitated prior to taking the sample should be pretty representative. Few have this luxury. Sand bedding in dairy systems create a stratified manure, which causes a variance in the nutrients. This spring, take 3-5 manure samples over the course of emptying the pit. Freeze and mail these to a manure laboratory and then see how and if the manure nutrients changed. Keep records of where the manure from the various samples ended up in the field and follow that crop through to harvest. For a farm that only hauls manure once or twice a year, spring may be the only opportunity to collect a new manure sample for months, so don’t miss that opportunity. Since minimal agitation may occur from a swine finishing barn, several samples may also be helpful in these systems.
- Does your manure sample include both ammonium and total nitrogen? Be sure and ask for both, even if it costs a little more. The more ammonium in the manure, the more important rapid incorporation can be. The same manure, surface applied over various temperatures and several days to incorporation can create significantly different rates of nitrogen being available during the peak need of the corn crop.
- Once you have quality manures samples, focus your energy on application rates and calibration. Again, with sand bedding, the rate can change over the course of the day based on sand accumulation in the manure tank, and how much sand is being hauled with each load as the manure pit changes from liquid to more solid consistency. Calibrate and plan for the desired rate, but check that rate at the end of the day too. Knowing how many total gallons were hauled on a given amount of acres is a way to calibrate in hindsight. This helps catch skips and or overlaps of manure that could be throwing off the per acre rate. Make a correction for the next day. In a straight sided manure storage, one method is to measure the depth of manure at the beginning of hauling, then at the end of hauling and calculate the total gallons that have been hauled. This measurement with probably be in cubic feet, remember there are 7.48 gallons in every cubic foot.
With the best laid plans, the spring weather has the last say on nitrogen availability at the time of greatest need for the corn. A pre-sidedress soil test can help evaluate this condition and an instructional video can assist farmers on how to take a PSNT. Plan now to take strategic soil samples at side dress time: sample from a representative amount of fields that reflect your hauling practices and manure sources. For example: compare fall to spring applied manure from the finishing barn. Compare winter daily haul to spring incorporated. Compare a field that has received manure every year to a field that is just getting manure. Compare the milking herd to the heifer barn. Whatever variances occur on your farm, sample from those distinct systems. To really see the difference, also compare a field that has had no manure. The results will build confidence in your fertilizer program. For more information, visit www.animalagteam.msu.edu.