CRP Targeting for Wildlife Habitat: A New Indicator Using the 1992 National Resources Inventory
Congress has wrestled with the issue of which land should be enrolled in a renewal of the Conservation Reserve Program (CRP), considering that benefits to wildlife from CRP are substantial. This paper evaluates the amount of land that may qualify for CRP enrollment in order to provide high-value wildlife habitat and to present the potential enrollment costs. The assessment is based on a wildlife habitat indicator developed from the National Resources Inventory conducted by the Natural Resources Conservation Service.
Wetland Soils of the Prairie Potholes
Publisher Summary The chapter discusses the wetlands of the prairie pothole region (PPR). The two important hydrologic factors are climate and topography that explain the existence of wetlands in any landscape. PPR wetland soil development is based on hydrologic processes and conditions created by a climatic gradient as impacted by topography, sediment lithology, and stratigraphy. The most important systems used to classify wetlands in the PPR include the United States Fish and Wildlife system; the Stewart and Kantrud system; and an extension of the Stewart and Kantrud system that incorporates hydrology and landscape position. The dominant water quality considerations for wetlands in the PPR are increased sedimentation from cultivation; and salinity associated with hydric soils, groundwater, and surface water. Wetland soil properties that have the greatest influence on current land use include soil moisture dynamics, soil aeration, and salinity. Using principal components analysis (PCA), Richardson and Bigler found that principal component factors reflecting salinity, organic matter accumulation, calcium carbonate dynamics, and texture, respectively in order of importance, explained most of the observed variations in PPR wetlands. In the PPR, three soil types have been observed in nonfen wetland edges: the Calciaquoll without salinity and gypsum; the Calciaquoll with salinity and gypsum; and the Natraquoll.
On the definition and identification of aquic soil moisture regimes
The definition of an aquic soil moisture regime given in Soil Taxonomy is difficult to understand and, in places, ambiguous. The essence of the definition as written, however, is the requirement for reducing conditions. A soil which is saturated with groundwater or with capillary fringe water may, or may not, have an aquic moisture regime. Reducing conditions are defined in Soil Taxonomy in relation to the virtual absence of dissolved oxygen, though morphological criteria for the differentiation of soil classes are based on the reduction and segregation of iron. The absence of requirements relating to duration of reducing conditions, or to the thickness of reduced soil, suggests that the definition was intended to apply to soil material rather than to a pedon. The aquic moisture regime has a particular depth connotation only when it is applied to the differentiation of soil classes. A simple field test, based on the complexing agent a,a?-dipyridyl, is useful for the identification of ferrous ions in soil solutions and hence is potentially useful in the recognition of aquic moisture regimes. The sensitivity of this test limits its usefulness to those soils which contain more than about 0.5% free iron (i.e. iron which can be solubilised as iron(II) under reducing conditions as measured by extraction with dithionite reagent).