Drainage System Effects on Physical Properties of a Lakebed Clay Soil

Abstract

The long‐term effects of drainage on physical properties of a lakebed silty clay soil were evaluated 16 years after initiation of a field experiment. The treatments were undrained, surface drainage, subsurface drainage, and a combination of surface and subsurface drainage. Soil conditions were characterized by surface penetration resistance and by unconfined compressive strength, hydraulic conductivity, and pore size distribution in the 0–30 cm depth. Subsurface drainage resulted in greater soil hydraulic conductivity, less unconfined compressive strength, and less surface crust resistance than treatments without subsurface drainage. Subsurface drainage also decreased bulk density and increased the volume of air‐filled pores at 0.02 to 1.0‐bar suctions, but these effects were of smaller magnitude.An alfalfa (Medicago sativa L.)‐timothy (Phleum pratense) mixture was grown during the period of these measurements. The survival of alfalfa and the total hay yield decreased in the order: combined surface and subsurface drained, subsurface drained, surface drained, and undrained treatments.

Surface Runoff and Soil Physical Properties as Affected by Subsurface Drainage Improvement of a Heavy Clay Soil

“…The measurements thus show that during the ten years the structure of the soil had been improved also between the drain trenches to allow less surface runoff (Aura 1990) than before. While the effects of subsurface drainage improvement on soil properties have been seldom reported, subsurface drainage as such has been found to increase the volume of air-filled pores (Hundal et al, 1976) and saturated hydraulic conductivity (Bouma et al, 1979) of undrained clay soils.…”

“…porosity and aggregation, markedly affects the cultivability, workability and hydrological properties of clay soils. Subsurface drainage has been reported to improve the aggregation and aggregate stability of clay soil (Baker et al 2004) and to increase the volume of air-filled pores (Hundal et al, 1976) and saturated hydraulic conductivity (Bouma et al, 1979) of clay soils. According to Mokma et al (2000) and Yli-Halla et al (2009), the lowering of the groundwater table by subsurface drainage has markedly affected the structure development of Finnish clay soils.…”

Subsurface Drainage for Rehabilitation of Waterlogged Saline Lands: Example of a Soil in Semiarid Climate

“…The higher soil porosity under the drained condition was evidently the result of a higher proportion of both large and medium sized pores. Hundal, Schwab, and Taylor (1976) also reported a decreased bulk density and increased porosity under subsurface drainage conditions in clay soils. Leaching of excess soluble salts resulted in more favorable conditions for water availability as compared to the undrained saline soil.…”

Change of soil hardness and soil properties due to tile drainage in the Red River Valley of the North

“…However, Van Hoorn (1958 found that micropores were more evident than macropores in a subirrigated soil. Research results also differ on whether drained soils can decrease the amount of surface crusting (Hundal et al, 1976;Lal and Fausey, 1993). When a soil crust develops, the soil hardness increases and the power required for tillage is also increased.…”

“…Soil bulk density has been shown to decrease when drainage and subirrigation have been used compared to undrained soils (Chieng and Hughes-Games, 1995) and soil bulk density has also been shown to be lower in subirrigated soils compared to drained soils (Baker et al, 2004). This decrease in bulk density in some studies may have been the result of an increase in soil macropores compared to micropores (Baker et al, 2004;Hundal et al, 1976). However, Van Hoorn (1958 found that micropores were more evident than macropores in a subirrigated soil.…”