Things Your Dad Never Told You about Manure
If you’re like me, you learned a lot from your Dad. On the farm and off, Dad’s advice was usually spot on. While we need to embrace those historical lessons, we also need to remember that the world is a lot different than it was in Dad’s day. Especially when it comes to manure land application, we need to look for opportunities to save money and improve efficiency on the farm.
Same rations as Dad’s?
The first option must be to consider reducing the P concentration in the ration. Abundant research results now support feeding less P than in past decades. For example, current NRC (2001) recommendations are for ration P concentrations for lactating cows to be between 0.32 and 0.38% of the ration dry matter, depending upon level of milk production.
An easy rule of thumb is that 1 gram of ration P should be provided for each pound of milk produced (Get details in article by Rozeboom and Beede at www.animalagteam.msu.edu/DietModification/tabid/203/Default.aspx).
Do you feed the non-milking herd the sane as the milking herd?
The milking herd manure has more nutrients and is generally more concentrated per ton or per 1,000 gallons. It also is more cost-effective to deliver to crop fields with the lowest P soil test. Those fields are probably farther from the manure storage, but when the nitrogen (N) and potassium (K) are also accounted for at today’s fertilizer prices, hauling becomes more cost effective if the nutrient credits are valued and fertilizer applications are reduced accordingly.
Did Dad test manure? Do you?
Are you collecting more rain and wash water?
Between the storm water, wash water and the sand settling in the storages, there is always some form of watery manure with low nutrient concentrations. But often, the agronomic rates for nutrient needs would require too much volume on the fields, resulting in run-off or liquid manure reaching tile drains. That means having to lower the rates to what the soil can absorb and retain. For more information visit www.animalagteam.msu.edu.
Did Dad teach you about organic and ammonium N?
On hot, dry days, the ammonium volatilizes into the air and is lost within hours. That’s when injection or same-day incorporation is vital. Whenever possible, apply manure later in the fall, when soil temperatures drop below 50 degrees F. This slows or stops the N conversion in the soil, holding more of the manure N in the ammonium form and binding it to soil particles over the winter.
Besides being potential risks for surface water contamination, while nutrients are washed away and become a pollutant the producer is losing money. A cover crop provides a root system to uptake nutrients and stabilizes soil. The roots also create better absorption of manure into the soil compared to a field of stubble after silage harvest. The top growth will reduce runoff.
The entire system puts organic matter back into soils. And, recent research at the USDA ARS National Soil Tilth Laboratory in Ames, Iowa is finding a positive interaction of the manure nutrients hastening the breakdown of the cover crop in the spring and then releasing nitrogen back to the following corn crop at the peak of crop need. Visit www.animalagteam.msu.edu for more information on rye cover crops.
An opportunity for you that Dad didn’t have
Dad, grandpa and you all know that manure has value. Grandpa valued it because he didn’t have fertilizer. Dad became accustomed to convenient and inexpensive fertilizers. That’s not the case anymore. Manure has extraordinary value: manage it, credit it and pass the nutrients on to your kids.
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