| Autor: |
Baker, Barbara J. |
| Jazyk: |
angličtina |
| Rok vydání: |
2002 |
| Předmět: |
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| Druh dokumentu: |
Text |
| Popis: |
Research was conducted to determine how water table management affects select physical properties and carbon fractions of a Hoytville clay loam soil. The research took place at the Northwest Branch of the Ohio Agricultural Research and Development Center in Wood County, Ohio. Water table management treatments included subsurface drainage and subsurface drainage with subirrigation. Subirrigation was applied during the vegetative, flowering and seed fill stages of crop growth to maintain a constant water table at 0.25 m below the surface and prevent moisture stress in the crops. The cropping system was a corn soybean rotation with fall tillage with a chisel for both crops and spring leveling with a Roterra before planting soybeans. Results show a difference in water stable aggregates (WSA) at a depth of 0.4 – 0.75 meters with the subirrigated treatment having a lower percentage of WSA. The mean weight diameter of aggregates in the subirrigated treatment was smaller than in the subsurface drainage treatment at a depth of 0.3 – 0.75 meters. A shift in the pore size distribution toward smaller pores in the subirrigated treatment further supported “loss of stable soil structure” theory for the subirrigated treatment. Penetration resistance measurements also revealed a change in the structural stability of the soil at a depth of 0.30 – 0.45 meters. No differences were seen between water management treatments in the carbon fractions of the upper 0 – 0.20 meters of the soil. The CENTURY model was tested to determine if it could be used to predict levels of soil organic matter as a result of subirrigation. The model was unable to predict the amount of total SOM in the soil unless the starting value of carbon was lowered well below actual values. Subirrigation of the Hoytville soil led to a loss of stable structure at a depth of approximately 0.40 meters in the soil. The exact reason for the loss of soil structure is unclear but may be related to long periods of saturation resulting from the subirrigation. |
| Databáze: |
Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
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