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Nutrient Management

Manure Testing

Why Test Manure?

Manure is an excellent source of many essential plant nutrients that with proper management can meet all or a significant amount of the nutrient needs of most crops. The key to managing manure for maximum economic benefit from the nutrients and minimum environmental impact is to know exactly the amount and, in some cases, the form of nutrients in the manure. Unlike fertilizer, manure analysis and form can vary widely.

Average values and the range of values for liquid dairy manure samples submitted to the Pennsylvania State Agricultural Analytical Services over a period of time. The averages in the boxes are very close to most published “book” values for dairy manure but the range in individual analyses is very wide. Summaries from many other labs have shown similar results.

What Can Cause Variation in Manure Nutrient Content?

Even on a single farm, the analysis of manure can vary significantly over time due to management and weather conditions. Other sources of variation include animal feeding, manure handling, manure storage, dilution with rain or wash water. Without a manure analysis an individual farmer has no way of knowing if the manure on his farm is close to the average analysis or if it is on the extreme ends of the range.

Finally, a single manure source can have a large variation if the manure is not thoroughly mixed before spreading. Manures must be analyzed on a regular basis especially when changes in management or conditions occur.

Recommended Steps For Manure Testing

• Step 1. Manure Sampling
  
  • Solid Manure Sampling Procedures
  • Liquid Manure Sampling Procedures
• Step 2. Manure Test Results
  
  • Common Manure Test Results Conversions
    • Estimating Manure Density
• Step 3. Total and Available Nutrients
  
• Step 4. Manure Test Record Keeping

Page Authors: Douglas Beegle, Pennsylvania State University and John Peters, University of Wisconsin
Reviewers: Jerry Martin, Pennsylvania State University and Rick Koelsch, University of Nebraska