Sampling and Submitting Livestock Waste for Analysis

cindye
CINDY EVENSON
AGRONOMIST/CCA

Warm weather has returned, and most of your growers probably have spring fever. Those with livestock operations are probably starting to haul or thinking of hauling manure to their fields. Getting a representative manure sample can be tricky. Here are some guidelines that you can use or better yet, give to your growers to collect manure samples. Having a representative manure sample is the basis for a good nutrient plan. We all know that manure is quite variable, and completely different than working with the very precise analysis of commercial fertilizers.

Solid Manure – Dairy, Beef, Swine, Poultry

Obtain a representative sample using one of the methods below. The sub samples can either be mixed in a 5 gallon bucket, or piled on a cleared area, then shovel from the outside to the inside of the pile until well mixed. From the thoroughly mixed sample take a sub-sample and fill a plastic sample bottle or heavy-duty plastic bag half full. Tightly seal the container and store sample in the freezer if not delivered to the lab immediately.

  1. Sampling while loading – Recommended method for sampling from a stack or bedded pack. Take at least 5 samples while loading several spreader loads and combine to form one composite sample.
  2. Sampling during spreading – Spread a tarp in the field and catch manure from one pass. Sample from several locations and create a composite sample.
  3. Sampling daily haul – Place a 5-gallon pail under the barn cleaner 4-5 times while loading a spreader. Repeat sampling 2-3 times over a period of time and test separately to determine variability.
  4. Sampling poultry in-house – Collect 8 -10 samples from throughout the house to the depth the litter will be removed. Avoid sampling near feeders and waterers.
  5. Sampling stockpiled manure – Take at least 10 sub samples from different locations around the pile and at least 18 inches below the surface.

Liquid Manure – Dairy, Beef, Swine

Obtain a representative sample using one of the methods below. The sub samples can be mixed in a 5-gallon bucket. From the thoroughly mixed sample take a sub-sample and fill a plastic sample bottle half full. Tightly seal the container and store sample in the freezer if not delivered to the lab immediately. Liquid manure samples can build up pressure very quickly when warm. It is recommended to freeze liquid manure samples prior to shipping to the laboratory.

  1. Sampling from storage – Agitate the storage facility thoroughly (2 to 4 hours minimum) before sampling. Collect at least 5 sub samples to form one composite sample.
  2. Sampling during application – Collect at least 5 samples from buckets that are placed around the field, as the manure is being spread or irrigated. If this is not possible collect the samples as the manure is being pumped from the storage facility. Mix the sub samples to form one composite sample.

Identify the sample container and fill out a sample information sheet to send to the lab. Keep the manure samples frozen until they are ready to be shipped or delivered to the lab. Be sure to ship early in the week to avoid the samples being in transit over the weekend. All manure samples should be sent to AGVISE Laboratories in Benson, MN. Once the Benson lab receives a manure sample, the average turn around time is 3-5 days, so plan accordingly with your growers. AGVISE Laboratories has sample bottles and bags available for taking manure samples. Just call Benson at 320-843-4109 or Northwood at 701-587-6010 to get your manure sampling supplies.