Crop production on duplex soils in south-eastern Australia

Abstract

The environment, duplex soil types and trends in crop production in South Australia, southern New South Wales, north-eastern and north-central Victoria, the southern Wimmera and the Victorian Western District are reviewed. In the latter 2 regions, pastoral industries dominate and crop production is curtailed by regular and severe soil waterlogging, except for limited areas of lower rainfall. Subsurface drainage can eliminate waterlogging, but is feasible only for the Western District where subsoils are sufficiently stable. The other regions all have a long history of soil degradation due to cropping practices, but these effects can now be minimised with the use of direct drilling and stubble retention cropping methods. A vigorous pasture ley phase is still considered necessary to maintain nitrogen levels and to restore soil structure to adequate levels for sustainable farming. Future productivity improvements will require increased root growth in the subsoils. Deep ripping, 'slotting' of gypsum, and crop species capable of opening up subsoils are techniques which may hold promise in this regard. The inclusion of lucerne, a perennial species, in annual pastures and intercropping at intervals is a technique being pioneered in north-central and western Victoria and may provide the best opportunity to crop duplex soils successfully without associated land degradation.

Enhancing crop yields in the developing countries through restoration of the soil organic carbon pool in agricultural lands

“…Therefore, an increase in SOC concentration would produce the same level of crop yield with a reduced level of fertilizers (Vallis et al, 1996;Aggarwal et al, 1997) because of an increase in fertilizer-use efficiency and a decrease in nitrate leaching (Vallis et al, 1996). Increases in the SOC pool also enhance soil structure and aggregation (Tisdall and Oates, 1982;Stengel et al, 1984;Haynes and Swift, 1990;Feller and Beare, 1997;Haynes and Naidu, 1998;Gardner et al, 1992;Hamblin and Davies, 1997;Karlen et al, 1994), making soils less prone to crusting and compaction (Diaz-Zorita and Grosso, 2000) and soil erosion (Schertz et al, 1994;Benito and Diaz-Fierros, 1992).…”

Subsurface Lateral Flow in Texture-Contrast (Duplex) Soils and Catchments with Shallow Bedrock

“…Texture-contrast soils are associated with a range of management problems including waterlogging, poor crop establishment, crusting, poor root penetration, desiccation, wind erosion, water erosion, tunnel erosion, salinity, and poor nutritional status [4,[11][12][13][14][15][16]. Texture-contrast soils are naturally very hard setting [17] and suffer low infiltration rates and poor water holding capacity [18], which is accentuated where excessive cultivation has occurred [13]. The presence 2 Applied and Environmental Soil Science of massive, poorly drained subsoils results in regular seasonal waterlogging, which results in poor aeration for roots, nitrogen deficiency, and increased manganese levels where pH is low [13].…”

“…Texture-contrast soils are naturally very hard setting [17] and suffer low infiltration rates and poor water holding capacity [18], which is accentuated where excessive cultivation has occurred [13]. The presence 2 Applied and Environmental Soil Science of massive, poorly drained subsoils results in regular seasonal waterlogging, which results in poor aeration for roots, nitrogen deficiency, and increased manganese levels where pH is low [13]. Reduced crop yields in texture-contrast soils result from soil erosion, crusting, limited rooting capacity, poor aeration resulting from the slow movement of soil water through the upper B horizon, and confining of roots to shrinkage cracks and ped faces in the subsoil [19][20][21][22][23][24][25].…”

“…Reduced crop yields in texture-contrast soils result from soil erosion, crusting, limited rooting capacity, poor aeration resulting from the slow movement of soil water through the upper B horizon, and confining of roots to shrinkage cracks and ped faces in the subsoil [19][20][21][22][23][24][25]. In landscapes with sufficient slope, perched water-tables may be exacerbated by lateral movement of water on the upper surface of the B horizon leading to waterlogging and salinity in lower parts of the landscape [13,22,26].…”

Hydropedology and Preferential Flow in the Tasmanian Texture‐Contrast Soils

“…Estimates of the extent of texture‐contrast soils range from 17.0% (Isbell et al, 1997) to 20% of the Australian landmass (Northcote, 1979; Chittleborough, 1992), including around 80% of agricultural regions in southern Australia (Chittleborough et al, 1994) and approximately 60% of agricultural regions in southwestern Western Australia (Tennant et al, 1992). The texture‐contrast soils are associated with a range of management problems, including waterlogging, poor crop establishment, surface crusting, poor root penetration, desiccation, water repellence, wind erosion, tunnel erosion, salinity, poor nutritional status, hard setting, low infiltration, and poor water holding capacity (Edwards, 1992; Gardner et al, 1992; Tennant et al, 1992; Doyle and Habraken, 1993; Cotching et al, 2001; Hardie et al, 2007; Simeoni et al, 2009). Unlike other soil types, texture‐contrast soils contain an abrupt increase in clay content between the topsoil and the subsoil, which has been widely reported to result in the formation of seasonal perched water tables and subsurface lateral flows (Turner et al, 1987; Gregory et al, 1992; Naidu et al, 1993; Chittleborough et al, 1994; Cox and McFarlane, 1995; Fleming and Cox, 1998; Stevens et al, 1999; Eastham et al, 2000; Cox and Pitman, 2001; Cox et al, 2002; Ticehurst et al, 2003, 2007).…”