Browse on keywords: soil quality infiltration
Search results on 12/08/13
1024. Boyle, M., W. Frankenberger, L. Stolzy. 1989. The influence of organic matter on soil aggregation and water infiltration.. J. Production Agric. 2:290-299.
Describes a conceptual model for soil aggregate formation and stability. Soil organic matter contributes to improvement of soil structure in a number of ways. It enhances microbial action which produces more polysaccharides. Aggregation is the product of such forces as mechanical binding by roots and fungal hyphae, temporary adhesive properties by products of microbial synthesis and decay, and persistent cementing action by resistent humus components. Organic materials that decompose quickly (low C:N) had a rapid but ephemeral effect on soil structure. Plant materials that are more resistant to decomposition are slower but more persistent in changing structure. Soil polysaccharides are more complex and diverse than those derived from plants and microbes. Long-term pastures are ideal for aggregation. Good distribution of OM in soil is achieved from the fine roots of grasses, which can translocate as much as 50% of their photosynthate below ground. Green manuring rarely increases aggregate formation, but may inhibit its destruction. Cereals are similar to perennials in increasing % water stable aggregates formed during vegetative growth, but perennials are superior in maintaining the structure after the growing season. A grass-legume mixture is most effective at maintaining soil aggregation, while cereals and root crops are least effective.
2274. Greenland, D.J.. 1977. Soil structure and erosion hazard.. Soil Conserv. and Management in the Humid Tropics..
The structure of surface soil is usually given most attention in relation to soil erosion, because it is most subject to deterioration under raindrop impact, and due to agricultural practices its contition can be readily altered. However, subsoil structure is also important, as infiltration in a water-saturated profile is determined by the horizon of lowest conductivity.
6389. Smith, D.. 1990. Earthworms: digging out the facts.. Farm Journal Mid-January.
A no-till farmer considered earthworms the single most important factor for success of his system in Illinois. He used a simple infiltration test to demonstrate their impact. Infiltration rates remained high after several years of no-till even though soil bulk density had increased. Lime applications affected pH to a greater depth in a no-till field than a tilled field, probably due to earthworm action. Fields that were chisel plowed had only 25% as many worms the following spring as no-till or ridge-till fields.
7826. Zuzel, J.F., J.L. Pikul, and P.E. Rasmussen. 1990. Tillage and fertilizer effects on water infiltration.. Soil Sci. Soc. Am. J. 54:205-208.
Tillage and fertilization practices affect water infiltration. A long-term study at Pendleton, OR compared three tillages (plow, disk, and sweep) since 1940, and two rates of N (45 and 180 kg/ha) since 1962. Infiltration rates for plow, disk, and sweep were 17, 14, and 16 mm/h, respectively. Rates for the low and high nitrogen were 9 and 22 mm/h respectively. Results also indicate that surface sealing and soil frost are probably more important than tillage pans for infiltration. Residue cover eliminates any tillage effect on infiltration, while fertility is important in producing more crop biomass.