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Search results on 12/13/13
1688. Douglas, C.L.. 1983. Silicic acid and oxidizable carbon movement in a Walla Walla silt loam.. Ph.D Thesis, Oregon State Univ., Corvallis, OR. 75pp..
This study shows that use of ammonia fertilizers over the past 40 yrs, and particularly anhydrous ammonia in the past 15, has resulted in a more acid plow layer. The decrease in pH has caused soluble silica to leach out of the plow layer and led to cementation of the plow pan layer below 15 cm. The result is reduced water infiltration, increased water runoff and soil erosion, and increased soil water evaporation. Corrective applications of hydrated lime are explored. T: Mean silicic acid concentration in leachates from 15 cm soil layers as affected by long term N treatments. Long-term N and residue management effects on soluble carbon movement in four 15 cm layers. Soil pH and carbon addition effects on silicic acid concentration and transfer from the 0-15 cm layer.
5264. Pikul, J.L. Jr., R.R. Allmaras and C.R. Rohde. 1983. Water movement through tillage pans after 52 years of crop residue management.. OR Agr. Expt. Sta. Special Report 680, p.8-13.
The objective of this study was to measure and compare the saturated hydraulic conductivity in and below the tillage pan produced in plots which have received different treatments of crop residue management. Soil hydraulic conductivity was 35% lower on plots which had been fall burned as compared to plots into which strawy manure plus straw was incorporated. These results are consistent with the measured declines in soil organic matter and the development of denser tillage pans. Once a tillage pan is created (no matter how slight) mechanical compaction, water flow, and soil chemical changes (silica migration) may interact to form a nucleus for subsequent accelerated pan formation. T: Bulk density of soil where the straw residue was burned in the fall or straw plus 10,800 kg/ha strawy manure was plowed under in the spring. Saturated hydraulic conductivity and percent organic matter change since 1931.