Physiographic Regions of Iowa (Shapefile)

The state of Iowa contains diverse landscapes, each with subtle but impactful differences in their physical characteristics. This data set builds on the previously established landform regions of Iowa (Prior, 2000). All boundaries have been refined based on spatial data sets that become available since Prior (2000). Most importantly, this data set introduces subregions that …Continue reading “Physiographic Regions of Iowa (Shapefile)”

Evaluating the Accuracy of Ensemble Machine Learning and Statistical Uncertainty: Spatial Prediction of Topsoil Thickness in Iowa

Meyer Bohn and Bradley Miller – Iowa Water Center Conference April 6-8, 2021 Abstract The objectives of this study were to assess spatial predictions of topsoil thickness from models produced from ensemble machine learning algorithms along with assessing the uncertainty estimations associated with those models. Boosting is one example of an ensemble method, which attempts …Continue reading “Evaluating the Accuracy of Ensemble Machine Learning and Statistical Uncertainty: Spatial Prediction of Topsoil Thickness in Iowa”

Iowa Soil Drainage Class Maps [gSSURGO]

“Drainage class (natural)” refers to the frequency and duration of wet periods under conditions similar to those under which the soil formed. Alterations of the water regime by human activities, either through drainage or irrigation, are not a consideration unless they have significantly changed the morphology of the soil. Seven classes of natural soil drainage …Continue reading “Iowa Soil Drainage Class Maps [gSSURGO]”

Iowa Depth to Water Table Maps [gSSURGO]

“Water table” refers to a saturated zone in the soil. It occurs during specified months. Estimates of the upper limit are based mainly on observations of the water table at selected sites and on evidence of a saturated zone, namely grayish colors (redoximorphic depletions) in the soil. A saturated zone that lasts for less than …Continue reading “Iowa Depth to Water Table Maps [gSSURGO]”

Iowa Soil pH Maps [gSSURGO]

Soil reaction is a measure of acidity or alkalinity. It is important in selecting crops and other plants, in evaluating soil amendments for fertility and stabilization, and in determining the risk of corrosion. In general, soils that are either highly alkaline or highly acid are likely to be very corrosive to steel. The most common …Continue reading “Iowa Soil pH Maps [gSSURGO]”

Iowa Soil Saturated Hydraulic Conductivity (Ksat) Maps [gSSURGO]

Saturated hydraulic conductivity (Ksat) refers to the ease with which pores in a saturated soil transmit water. The estimates are expressed in terms of micrometers per second. They are based on soil characteristics observed in the field, particularly structure, porosity, and texture. Saturated hydraulic conductivity is considered in the design of soil drainage systems and …Continue reading “Iowa Soil Saturated Hydraulic Conductivity (Ksat) Maps [gSSURGO]”

Iowa Soil Clay Content Maps [gSSURGO]

Clay as a soil separate consists of mineral soil particles that are less than 0.002 mm in diameter. The estimated clay content of each soil layer is given as a percentage, by weight, of the soil material that is less than 2 mm in diameter. The amount and kind of clay affect the fertility and …Continue reading “Iowa Soil Clay Content Maps [gSSURGO]”

Iowa Soil Silt Content Maps [gSSURGO]

Silt as a soil separate consists of mineral soil particles that are 0.002 to 0.05 mm in diameter. In the database, the estimated silt content of each soil layer is given as a percentage, by weight, of the soil material that is less than 2 mm in diameter. The content of sand, silt, and clay …Continue reading “Iowa Soil Silt Content Maps [gSSURGO]”

Iowa Soil Organic Matter Maps [gSSURGO]

Organic matter is the plant and animal residue in the soil at various stages of decomposition. The estimated content of organic matter is expressed as a percentage, by weight, of the soil material that is less than 2 mm in diameter. The content of organic matter in a soil can be maintained by returning crop …Continue reading “Iowa Soil Organic Matter Maps [gSSURGO]”

Iowa Available Soil Water Storage Maps [gSSURGO]

Available water storage (AWS) is the total volume of water (in centimeters) that should be available to plants when the soil, inclusive of rock fragments, is at field capacity. It is commonly estimated as the amount of water held between field capacity and the wilting point, with corrections for salinity, rock fragments, and rooting depth. …Continue reading “Iowa Available Soil Water Storage Maps [gSSURGO]”

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