Reducing sampler error in soil research

Most soil sampling techniques are calibrated with standards and against each other, but the error introduced by the individuals performing each technique (sampler error) is often not addressed. We determined that sampler error explains a minimum of 5.5% of the variation in soil bulk density when using a composite coring technique. This source of error is of concern because it could easily obscure the small, but significant differences anticipated with long-term (decadal) research. We suggest three methods for increasing sampling accuracy across spatial and temporal treatments: (1) use > 5 individuals to sample each treatment; (2) consider both the concentration and pool size of soil properties (e.g. nitrate, root mass, etc.); and (3) include measurements of sampler error.