Farm soils loams

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. 

Pulleman M, Jongmans A, Marinissen J, Bouma J (2006) Effects of organic versus conventional arable farming on soil structure and organic matter dynamics in a marine loam in the Netherlands. Soil Use Manage 19 157-165... 

The movement of heavy farm machinery over a clay or loam soil can produce a marked deterioration of soil structure and aggregation (Parker and Jenny, 1945). In addition, the plow or cultivator disrupts aggregates. Under optimum moisture conditions, the harm done may not be serious. Also, compaction and aggregate disruption may not be markedly harmful on soils that are too dry, but can be extremely damaging on wet soils. The harm done is usually directly correlated with the fineness or texture, and indirectly with the amount of organic matter in the soil. 

The alkaloids of the genus Delphinium may be classified into two distinct structural types the atisine type, represented by ajaconine, and the lycoctonine type, represented by delcosine, acetyldelcosine, and delsoline (Figure 3.18). The common larkspurs are widely distributed in the western United States and in Canada where they are a common cause of cattle poisoning. Both types of alkaloids from Delphinium ajacis have been studied (Frost et al., 1967). Plants were grown in the field on sandy loam soil at the Horticultural Farm in Stillwater with normal fertilization and... 

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. 

---