Soil sampling equipment
Equipment for sampling and storage of (undisturbed) soil cores for soil and root analyses, Rhizons for soil pore water collection
VSI Soil corer. Soil cores are required in multiple types of studies, e.g. for soil profile description and classification, soil biogeochemical analysis, fine root sampling or microbial studies of the soil. We offer a complete set of soil coring equipment (soil sampling instrument, soil sample tube, soil corer) manufactured according to long-term experience and field approved.
VSI Storage and transport boxes for soil cores. We offer storage solutions for undisturbed soil samples -- fitting the diameter of your soil cores and variable in length.
VSI Soil Ring Sampler. The soil ring sampler can be used to sample undisturbed soil samples into soil sample rings (of custom diameter, height and material), e.g. for soil density measurements.
RRP (Micro-)Rhizon Samplers. The differently sized Rhizons can be used to sample soil pore water from Rhizoboxes and Rhizonboxes.
Soil Sampling Procedures
Sampling Design
A critical step in obtaining accurate soil tests is collecting representative samples in situ. Typically, uniform plots should be sampled in a simple random pattern across the field collecting at least 15-20 equal size soil cores to various depth. Alternatively, sampling transects can be installed. Avoid, or sample separately, areas which are obviously different like roads, eroded spots, low areas, and wet spots. In general, plots with significant landscape or other differences should be divided into separate sample areas. Differences may include soil types, slope, degree of erosion, drainage, land use history, or other factors that may influence results. More intensive sampling should be used where detailed information about within plot variability is needed.
Sampling Depth
Laboratory tests are calibrated to specific depths. It is vital to collect samples from appropriate depths because a core taken deeper or shallower will generate erroneous results. Sampling depth for most agricultural soils is typically the tillage depth, more skeleton-rich (forest) soils are often sampled to at least 30 depth, 10 of those mineral soil if large organic layers occur. The surface soil samples are typically used for conventional tests of organic matter, phosphorus, potassium, pH, and salt levels. Studying deep-rooted species such as wheat and barley might need deeper samples, e.g. to study nitrogen availability. Be sure to separate surface litter. Subsoil samples are often needed to estimate available nitrogen and to determine C stocks. Both surface and subsurface soil samples are needed to estimate root system depth distribution.
Soil Sampling Tools
A stainless steel soil sampling probe / soil corer is the most commonly used tool for collecting soil samples under normal conditions. The soil probe provides a continuous soil core with minimal disturbance to the soil that can be readily divided into various sampling depths.Specific storage solutions are available to transport intact soil cores to the laboratory. Even if compression in larger diameter soil corers can be small, any soil compression has to be avoided for determining soil density, thus specific soil ring samplers are used in a horizontal fashion in soil pit walls for soil density. Vehicle-mounted hydraulic probes are available and are a better choice under adverse soil sampling conditions if acees to the sampling site is provided and slope permits. Other tools include plastic sample bags, a tape measure / ruler to determine potential compression and a water proof marker for labelling. See the VSI soil corer manual for a comprehensive tools / packing lists for a soil sample campaign.
Selected Readings on Soil Sampling Methods
- Franzen, D. W. and T. R. Peck (1995). "Field soil sampling density for variable rate fertilization." Journal of Production Agriculture 8(4): 568-574.
- Forster, J. (1995). Soil sampling, handling, storage and analysis. Methods in applied soil microbiology and biochemistry, Elsevier: 49-121.
- Gregorich, E. G. and M. R. Carter (2007). Soil sampling and methods of analysis, CRC press.
- Guo, M. (2009). "Soil sampling and methods of analysis." Journal of Environmental Quality 38(1): 375.
- Liu, S., et al. (2019). "Estimation of plot-level soil carbon stocks in China's forests using intensive soil sampling." Geoderma 348: 107-114.
- Theocharopoulos, S., et al. (2001). "European soil sampling guidelines for soil pollution studies." Science of the Total Environment 264(1-2): 51-62.
- Van Groenigen, J. W., et al. (1999). "Constrained optimisation of soil sampling for minimisation of the kriging variance." Geoderma 87(3-4): 239-259.
- Veihmeyer, F. (1929). "An improved soil-sampling tube." Soil Science 27(2): 147-152.