SHP collects soil health and soil nutrient samples on working farms within the SHP network and works with various partners and service providers, including agronomists, soil samplers, and soil laboratories. This process is creating an in-depth data set to support farmers’ decisions and to understand changes in soil health over time.
SHP’s soil sampling process
Overview of the Process
In early spring, SHP assembles and mails soil sampling kits to the soil sampler, which may be an SHP field manager, an agronomist, or a soil sampling company. Each kit contains the materials and information necessary to pull the soil samples: a map of the field and sample points, barcode labels that correspond to the samples to be pulled, bags to hold the soil, and shipping materials to send the samples to the soil laboratories. Samples are shipped directly to the lab, where they are tested and the data is returned to SHP to analyze before sharing with the farmer.
- Soil sample kits contain the materials necessary for pulling the samples out in the field, labeling them properly, and shipping them to the appropriate lab. Samplers supply their own soil probe and buckets.
- Each kit is customized for each field in the SHP program. Barcode labels are printed and sampling bags are counted out each year to meet the needs of each site. This helps guarantee a high level of data quality across the SHP network.
- All kits and samples are tracked throughout the process to ensure timely results.
- Soil samples are typically collected in the spring, after the ground is workable but before planting. Sampling occurs at the same time each year to minimize the effects of weather and seasonal movements of mobile nutrients.
- Using the map and shapefile of predetermined sample points, the soil sampler uses a GPS to navigate to sample points.
- For soil nutrient sampling, the sampler uses a soil probe to take 15 soil cores in a 30-foot diameter circle around a sample point to a 6-inch depth. For each soil core, the sampler separates the core at the 2-inch mark to collect soil that represents the 0- to 2-inch depth and the 2- to 6-inch depth. SHP strip trials are sampled for soil nutrients on a 1-acre grid pattern across the field, and SHP side-by-side trials have 1-3 samples for each management system.
- For soil health samples, the sampler also pulls soil cores on a 30 ft. diameter circle around the soil sample point to six inches. In an SHP strip trial, the sampler combines the soil from all soil sample points within a strip to create a composite soil health sample over two or more soil sample points. SHP side-by-side trials have 1-3 samples for each management system.
- For every sample, the soil sampler bags soil and adheres a barcode that tells SHP and the lab where the sample was pulled and what type of analysis it will be getting.
- Samples are sealed in respective bags, boxed up, and sent to the lab.
- Soil nutrient samples are analyzed for macro- and micronutrients, including phosphorus, potassium, sulfur, zinc, iron, manganese, copper, calcium, magnesium, sodium, boron, and aluminum, along with soil organic matter, pH and buffer pH.
- Soil health samples are analyzed for soil carbon, respiration, active carbon, aggregate stability, available water capacity, and ACE soil protein.
Soil sample results are returned to the farmer after analysis and incorporated into the SHP dataset. The farmer may use the sampling results to make management decisions or track progress over time. However, sampling for soil health indicators is still a relatively new process, and indicators may change slowly with management changes or be affected by sampling and field conditions in a particular year. SHP encourages farmers to look at longer-term trends in sampling as we contribute to a broader effort to understand soil health.
Soil sampling at-a-glance
The agronomist or soil sampler will:
Navigate to the field's sampling points with GPS.
Separate each core at the 2-inch mark to create two samples for 0-2 inches and 2-6 inches.
Bag each sample and adhere a barcode that marks the location and type of analysis.
Take 15 soil cores in a 30-foot diameter circle around a sample point to a 6-inch depth (using a soil probe).
Follow the soil sampling instructions for that particular field trial type.
Seal samples in respective bags, box up, and send to the lab.
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Find Out More
Learn more about soil sampling and the soil health indicators SHP is evaluating.