There has been increased public concern in the USA over the long‐term impact of urbanization on the available land used to produce food, feed, and fiber. Concern that urban use of highly productive soils may threaten our food security and sustainability has been debated for nearly three decades. This study was primarily initiated to compare different soil productivity classes in terms of areas and proportion of land converted to urban uses in the USA. The methodology consisted of analyzing data resulting from a geographic information system (GIS) overlay of urban land use maps derived from the Defense Meteorological Satellite Program's Operational Linescan System (DMSP/OLS) nighttime imagery and layers of potential soil productivity. Soil productivity distributions were obtained using the Soil Rating for Plant Growth (SRPG) model based primarily on soil and landscape parameters contained in the State Soil Geographic (STATSGO) database. Currently, the urban land use covers ≈3% of the conterminous USA and is primarily on areas that were originally of low and moderate soil productivity. Only 6% of the total land under urbanization had consisted of highly productive soils. However, land with highly productive soils, roughly 3% of the total U.S. area, has a higher level of urbanization (5%) than that of any other soil productivity category. States differ in the areas and proportion of land converted to urban uses in each soil productivity class. These results are a first step in determining the current status of soil resources in relation to urbanization and should be interpreted according to the scale and resolution of data sources and assumptions made in the soil productivity modeling.

In soils of sandy, coarse loamy, fine loamy, fine silty, and fine particle‐size families, we observed some general relationship between water table depths and soil color pattern. Horizons that have dominantly gray (chroma ≤ 2) color in the matrix or argillans are saturated much of the year. Horizons that have gray mottles, but are dominantly brown, are saturated a few months of the year if they are above the dominantly gray horizons, or are saturated most of the time if these horizons are below the dominantly gray horizon. Horizons that have dominant chroma of three in the matrix, mottles, or argillans are often saturated. Those that have dominant chroma of five or six and have no mottles with chroma of three or less are seldom or never saturated. This study shows that soils with three‐chroma matrix, mottles or argillans are much wetter than they had been thought to be and are wetter than reflected in Soil Taxonomy definitions.

Abstract. On cultivated cropland, soil quality of reclaimed soils after surface mining for coal can be lower than that of the quality before mining. The objectives of the study were to evaluate near surface and profile soil quality on eight soils reclaimed to agricultural land in southwestern Indiana. Several near-surface properties were measured and a soil quality index score calculated from a minimum data set (MDS) of six indicators. The scoring function ranges were based on the soil condition before mining. The near-surface properties of bulk density, soil strength, aggregate stability and particulate organic matter (POM-C) were within the limits observed for cultivated surface horizons. However, surface properties could be improved through best management practices. The profile soil quality was lower on all eight reclaimed sites. The index scores ranged from 68 to 87 on a scale from 0 to 100. The properties that were a major factor in lowering the soil quality of the reclaimed soils were a poor or massive soil structure, lower available water capacity, and increased bulk densities. Organic C, CEC, and soil pH on most sites were generally comparable to the condition before mining. The poor or massive structure, higher bulk densities, and lower AWC of the reclaimed soils could result in water stress and/or lower productivity. Under doughty conditions especially under doughty conditions compared to the reference soil condition before mining.Additional Key Words: soil quality index, POM, near surface properties.

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One reason for the slow implementation of conservation tillage methods on the nation's farms is the perception that results from plot‐level research at the agricultural experiment stations—presently the primary information source for interpreting the relative crop yield potential of alternative tillage systems—may not be representative. In this study, data for corn (Zea mays L.) production from 78 sites in Wabash County, Indiana, were obtained from cooperating farmers as part of their normal farming operations during 1983. The data were analyzed with simulation models, regression techniques, and partial budgeting. The average farm corn yields, and hence net returns, observed from different tillage systems appeared to be significantly different, corn on ridge‐till sites yielding substantially more than corn on conventional and no‐till sites. After differences among sites in precipitation and soil characteristics—expressed as a single moisture stress variable—and applied N and P fertilizers were taken into account, however, there were few yield differences among tillage systems, reconciling the farm findings with those from universities. The moisture stress variable (S) was the sum of 90 daily ratios of actual‐to‐potential evapotranspiration, from 39 d before corn silking to SO d after. The study also provided empirical evidence that, as moisture stress increased, net returns to those corn producers using no‐till systems increased over those obtained for other tillage systems. Although the extensive data gathering was done in only 1 yr, that year (1983) provided as much range in the moisture stress variable (S=15 to 45) and final corn yields (7 to 160 bu/acre among sites) as might be expected from a single soil plot over 10 or more years in Indiana. Therefore, the results are believed to provide a representative view of the yield‐moisture stress relationships, especially at the high moisture stress end.