Sampling Dairy Manure


Successful livestock and dairy farmers have learned a long time ago to take advantage of animal manure as a valued source of plant nutrients for their cropping programs. Using manure can greatly reduce fertilizer needs and thus the expense of purchasing off-farm nutrients. Manure is an excellent source of all major and micro nutrients required by crops. However, the composition of manure is affected greatly by many factors such as feed ration, type and amount of bedding, manure storage and handling, method of land application as well as soil characteristics. Therefore, large differences in manure nutrient content are expected and known to exist from farm to farm. For example the nitrogen content of solid animal manure may vary from 3 to 33 lb/ton and the phosphorus content from <1 to 35 lb/ton.


In order to maximize the economic value of manure we should see it as being as essential as knowing the analysis of the fertilizer and feed concentrates you purchase. Knowing your manure analysis is an important, must know component of nutrient management planning. This information alone can save you money and help ensure productive crops.


Procedures for Manure Sampling

Manure contents may vary throughout the year as feed or other inputs (bedding, wash water, rain) change and with storage type. For most precise results samples should be taken near or at the time of application.


a) Sampling Solid Manure:

  1- Take min. 6 samples from different places in stack.

  2- Avoid sampling from crust (it is lower in nutrients).

      3- Samples may be taken from spreader. Take samples from min. 6 different loads.

      4- Mix samples in a clean soon to be smelly plastic bucket and take a composite sample for lab analysis.

  5- Keep samples cool to prevent ammonia N loss.

      6- Freeze the sample before sending it to the lab for analysis. Use a rapid transit courier.


b) Sampling Liquid Manure:

  1- Agitate the manure storage before sampling.

  2- Use a bucket on a rope to throw into manure storage.

      3- Mix sub-samples in a larger bucket and take a composite sample.

      4- A better method is to take samples from different loads during loading the manure spreader.

      5- Sample may also be taken at the time of application. Place 3-6 small buckets at several locations in the field. Mix and take a composite sample. 

      6- Freeze the sample before sending it to the lab for analysis. Use a rapid transit courier.


Masoud Hashemi and Stephen J. Herbert

Dept. of Plant and Soil Sciences

University of Massachusetts and

Dept. of Environmental Protection

s319 Nonpoint Source Pollution Program

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Last updated: 11/11/02.