2008-05-01_REVISION - M1973007SG (5)

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SOILS INFORMATION overgrazing. The predominant species in 1992 was Blue Grama which indicated the site may have been recovering from severe disturbance. Typically, Blue Grama does not compose a major part of the vegetation on this soil and becomes abundant only after rather severe disturbance such as overgrazing or severe drought. Since then, Blue Grama has declined some in significance as the needlegrasses have recovered and gained dominance. Some wheatgrasses are also more common as is Sand Dropseed and Prairie Sandreed. In general, the vegetation composition has shifted dramatically since 1992 and is now more in line with what would be expected on this site. Careful examination of the vegetation still shows evidence of previous disturbance even though that evidence is rapidly being obscured by a positive vegetation development direction. The weedy annual component is still present but is declining rapidly as the perennial species gain physical and numerical dominance. The typical brown layer under the dark upper layer is poorly developed and has an unclear boundary where it merges into the sand deposit. This could indicate the soil has never had the opportunity to develop as a typical Blakeland loamy sand. Its upland situation would certainly indicate that is a possibility. The apparently higher organic matter content than normal indicates there has been a large amount of use in the past which supplied more organic matter. It may have been grazed rather intensively. That could explain why wind erosion might have reduced the typically 11 inch deep surface layer. Overgrazing would have reduced the protection from wind by vegetation and resulted in significant soil loss. But the additional organic matter could have come from limited irrigation or the decomposition of cow manure, especially if supplemental feeding occurred. In summary, this soil appears to be atypical for a Blakeland loamy sand. The top layer is thinner and more organic than normal, and the subsoil layer is rather poorly developed. There is some evidence of cultivation having occurred at some time in the past. From this information the following history seems reasonable. The soil was rather poorly developed in the first place, as sandy soil usually are on and and semi-arid lands. Its upland location and exposure to strong west winds would reduce the rate of development. At the turn of the century it was probably grazed intensively which not only exposed it to wind erosion but also allowed Blue Grama to become an abundant species. When the Dust Bowl occurred the wind erosion became very severe and removed much of the upper soil layer. After the Dust Bowl, Blue Grama spread over most of the site and became a dominant species. To improve the range quality, seeding of the site was done with various species, especially on the west end where farming may have also been attempted. After finding the site would not support crops adequately, it was intensively seeded and organic matter was added. Since that time the Blue Grama and planted species spread over the site following protection from additional disturbances. As a result we have today a rather shallow, moderately organic, but sandy soil that supports a dense but low diversity vegetation. As noted previously though, this character is in a rapid state of flux with diversity increasing, the annual component decreasing, and productivity reaching toward a maximum. Unfortunately, the amount of duff remaining on the ground is considerable,but not so great as to start Daniels Sand Pit#2 Amendment (2008) Exhibit I Page 5 of 8