| Popis: |
Cattle feedlot manure at 0, 90, 180, or 360 metric tons ha⁻¹ year⁻¹ was incorporated with Sharpsburg silty clay loam to depths of 10, 20, and 30 cm. For plots tilled 10-cm deep, the heaviest applications increased the soil organic carbon content from 2 to 5% after 2 years. Particle density decreased from 2.63 to 2.50 g cm⁻³ and bulk density decreased from 1.05 to 0.90 g cm⁻³. Geometric mean diameter of water-stable aggregates increased from 80 to 800 µm. Modulus of rupture of soil cores decreased from 0.60 to 0.08 bars. Hydraulic conductivity of undisturbed soil cores increased five fold. Manure applications reduced the hydraulic conductivity of disturbed soils sampled in the fall, but there was no effect on spring samples. The heaviest application of manure increased the electrical conductivity of the hydraulic conductivity leachates from 0.8 to 3.2 mmhos cm⁻¹ in the fall samples and from 0.4 to 1.2 mmhos cm⁻¹ in the spring samples. The effects of manure on soil properties decreased with increased depth of tillage. |
