Revised Ranges For Manure Nutrient Availability For Crops

By John Sawyer

Based on current research results from Iowa and neighboring states, the Using Manure Nutrients for Crop Production publication (PMR 1003) was recently updated to reflect new manure nutrient availability ranges for crop production.

Beef cattle and dairy nitrogen availability ranges are now 30-50 percent of the total nutrients applied, and phosphorus ranges are 80-100 percent of total nutrients applied. These ranges increased slightly from 40 percent to 50 percent for the upper end of the nitrogen range and 60 percent to 80 percent for the low end of the phosphorus range.

Manure nutrient availability values are important when it comes to manure application, since the manure rate to supply crop available nutrients is calculated based on the specific manure source being used.

“For manure nitrogen and phosphorus, there is usually a mix of organic and inorganic materials that varies among manure sources, production systems, bedding, storage systems and handling,” said John Sawyer, professor and extension soil fertility and nutrient management specialist at Iowa State University. “These ranges account for the variety of factors that can affect nitrogen and phosphorus availability to crops.”

Additional text describing the table of manure nutrient availability values was added, along with the new URL for the revised Corn Nitrogen Rate Calculator website (cnrc.agron.iastate.edu).

Source:iastate.edu