The lower yields experienced by many farmers this year due to the drought can alter field nutrient requirements for next year, resulting in nutrient credits.

Lower crop yields may result in nutrient credits“Substantially lower yields experienced this year can lead to less removal of nutrients from a field,” according to John Lory, Extension associate professor, University of Missouri. “When nutrient uptake is reduced there is an opportunity to capture a drought nutrient credit from the stricken crop that may reduce fertilizer need in the year following drought.”

This year, corn and soybean fields have been harvested for grain, baled as forage or silage, grazed as forage, or been abandoned with no removal of crop. “The methods used in managing fields this year will directly affect the amount of fertilizer carryover to the next year,” according to Lory.

To read the report ‘Impact of the Drought on Next Year’s Fertilizer Rates’, click here.

Drought nutrient credits can be important particularly on fields where little or no material was harvested in 2012, according to Lory. Yet other crop removal scenarios may actually increase fertilizer need next year. “Chopped corn, for example, can increase potash requirements for next year’s crop.”

Lory also cites the potential for further nitrogen loss through leaching or denitrification if excessively wet conditions prevail between now and next spring. For more information on estimating next year’s nitrogen requirements, click here.

Regardless of the particular nutrient needs, farmers will need to be extra cautious this fall if applying liquid swine manure to dry fields. This year, the job may require lower application rates and multiple passes due to the cracks, or fractures, that have developed from the relentless heat. If the application rate exceeds the soil holding capacity, there is an increased risk that the manure will move off the field resulting in contamination of water bodies.

Before application, here are some ideas to consider. “First, check your state regulation as well as your operating permit and nutrient management plan,” says Matt Bradshaw, Bradshaw Custom Pumping, Griggsville, Ill. Bradshaw does custom application and also contract finishes 18,000 hogs per year.

Many times there will be regulations that limit total one-pass application rates depending, but not limited to, soil type, slope and soil conditions. “Before you start, make sure you are aware of current state regulations as well as the responsible agency and their contact information,” Bradshaw recommends.

Although Bradshaw has not encountered problems with leakage into drainage tiles this year, he monitors field tiles continuously during and after application. In the event there is evidence of manure in tile lines, Bradshaw recommends a set protocol:

1. Stop application in area affected.

2. Plug tile line to stop flow. Each crew carries commercial inflatable pipe plugs in case of leaks.

3. Find how far the liquid has traveled from end of tile and stop by damming up the area.

4. Always have a spill response kit, at a minimum, shovels, trash pump and plugs. Clean up affected area.

5. If release levels were high enough or liquid reached any surface waters, contact your state agency and file the proper spill reports.