Structure and Its Influence on Tilth of Soils

Abstract

The purpose of this study was to determine some of the changes that have taken place in the structure of several Corn Belt soils and its influence on tilth, permeability, volume weight, and percent of pores drained. Samples of soil were examined in the field to determine the type, class, and grade of structure, direction of natural fracture when lumps were broken, and size and number of visible pores. Six to twelve undisturbed soil core samples 3 inches thick and 3 inches in diameter were taken at random from each plot and depth to determine permeability, volume weight, and percent of pores drained at 60 centimeters tension. Many surface soils that originally were granular or crumb in structure have changed through cultivation and poor management practices to a fine fragmental or massive structure. With these changes in structure the percolation rate decreased from 8.4 inches to 0.2 of an inch per hour, percent of pores drained was reduced from 9.2 to 3.5, and the volume weight increased from 1.1 to 1.31. The surface crust was the least permeable layer in the upper 18 inches of the soils studied.

Modeling the Impact of Climate Change and Land Use Change Scenarios on Soil Erosion at the Minab Dam Watershed

“…As the results revealed, the highest amount of erosion was the result of the conversion of rangelands to agricultural lands due to reduction of soil organic matters and increased soil compaction that was also observed in the results of previous studies [74,75]. Another land use change that has had a great effect on erosion is the conversion of forest into rangelands and agricultural lands that has also been observed in studies by Mancino et al [76] and Wynants et al [77].…”

Development of Soil Survey Interpretations

“…These data, along with those from other research stations were used to assign values to individual soils. Soils were then classified based on actual observations and measurements Klingebiel, 1950, 1952;Klingebiel and O'Neal, 1952).…”

Decision support system for soil tilth assessment

“…Soil aggregation and organic matter changes were found to depend upon cropping treatment, as well as upon soil erosion (Wilson and Browning, 1945;Van Bavel and Schaller, 1950). Several studies evaluating the effects of tillage and cropping practices on soil tilth (Slipher, 1932;Faulkner, 1943;Browning and Norton, 1947;Lyon et al, 1950;Van Doren and Klingebiel, 1952;Klingebiel and O'Neal, 1952;Neal, 1953;and Melsted, 1954) found that under virgin conditions, the combination of structure, aggregation, organic matter content, and porosity resulted in nearly ideal soil tilth. The net effect of tillage practices, however, was decreased soil aggregation and organic matter content, and increased compaction and soil erosion; therefore, the result was reduced soil tilth.…”