Farm soils silts

The description of a soil in relation to the amount of mineral material, clay, silt and sand, is called the soil texture. There are large variations in the texture of soils found on farms. Soil texture can be analysed accurately in a laboratory but can also be assessed in the field using hand texturing. 

The following is a general farming classification based on some of the main soil types - clays, sands, loams, calcareons soils, silts, peats and peaty soils. 

For studies involving test substance application to soil, there may be a requirement for more soil information than for studies where applications are made to foliage of established crops. The study protocol should describe any specific requirements relative to soil type selection and how to confirm the soil characteristics for the study. Most studies simply require that the soil be identified by its name (e.g., Keystone silt loam) and composition (e.g., percent sand, silt, and clay). This information can typically be acquired from farm records, a soil survey of the local area, or a typical soil analysis by a local soil analysis laboratory. In some instances, a GLP compliant soil analysis must be completed. The study protocol must clearly define what is needed and how it is to be obtained. Unless specified in the protocol, non-GLP sources are adequate to identify the soil and its characteristics. The source of the soil information should be identified in the field trial record. 

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