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Livestock manures have been used as a crop fertilizer source for thousands of years. It continues to be a valuable source of crop nutrients, even with the advent of synthetic fertilizers. Because its nutrient content and availability can vary widely, it's important to develop a management plan that will optimize crop productivity while protecting water quality.

Topics include:

• Benefits and challenges of using manure in crop production
• What determines nutrient content in manure
• How manure storage and handling affect nutrient availability
• Importance of manure sampling and testing
• How application methods and timing affect nitrogen loss 
• Practices to optimize manure use and minimize nitrogen losses 

Please note: This course is self-paced. You may register at any point and complete the coursework when it is convenient for you.

A deep dive into the 4Rs starts where the original Nitrogen Smart ends with a detailed discussion on N rate, the contributions from soil and the stress from climate factors.

The 4Rs promote a nutrient management approach that balances crop productivity with environmental preservation:

• Right rate – Nitrogen rates have the potential to make the largest impact on both crop production and the environment. The key to optimizing rates is to follow university N guidelines, use soil nitrate-N tests when appropriate, and scout for deficiencies.
• Right source – Once in a plant-available form, the plant doesn't distinguish one N source from another. However, there are differences in how N fertilizers interact with the environment, which can affect both availability and loss.
• Right time – The nutrient supply should be synchronized with crop demand and uptake. Several factors influence N availability, including fertilizer source, the use of stabilizers or inhibitors, and field conditions. Together they help determine when it's most appropriate for that particular N source to be applied.
• Right place - Nutrients should be placed where the crop can use them. Consequently, the application method is important for optimum fertilizer efficiency.