Topsoil Evaporation in Water Repellent Soil Affected by Tillage and Claying: Preliminary Case-study Results

Soil water repellence represents one of the major soil constraints to broad-acre agriculture in southern Australia. Topsoil wettability is significantly reduced by the presence of hydrophobic organic compounds, resulting in poor seed germination, early plant establishment and ultimately lower yields. Soil mechanical disturbance (tillage) in combination or not with the addition of clay-rich subsoil (e.g. clay spreading) have been successfully adopted in the Australian broad-acre agriculture for the amelioration of water repellent sandy soils

Dynamics of water use by wheat and canola crops in compacted, acidic sands treated with deep tillage and lime

Incorporation of agricultural lime by ‘strategic deep tillage’ is one of the quickest methods for managing subsurface soil acidity. Such soil amelioration practice decreases soil resistance by removing compaction and increases soil pH, which allows deep penetration of crop roots, and hence increases the acquisition of soil water from deeper in the soil. As a result of improved soil physical and chemical properties, crop yield also increases and so does the water use efficiency (WUE). Under broadacre cropping conditions, WUE is generally estimated from crop yield and weather data; actual measurement of soil water uptake can lead to more accurate interpretation of results, especially where soil profiles are ameliorated to varying degrees

Variable aluminium toxicity and root distribution in acidic soil profiles

Subsoil acidity currently affects two thirds of the arable soils in the WA wheatbelt. At acidic soil pH, aluminium (Al) is solubilised from the solid phase into soil solution, creating a direct and localised toxicity to plant roots. Aluminium toxicity to plant roots constrains crop productivity by reducing root proliferation through soil, and inhibiting the capacity of roots to tolerate other constraints, such as compaction. Ongoing acidification of the subsoil is a direct artefact of the productive farming systems that are required to feed our world’s growing appetite for grain and livestock products

Strategic Tillage for Sustaining the Productivity of Broadacre Cropping in the Arid and Semi-Arid Regions of Southern Australia

Conventional tillage, usually practised before every cropping cycle, was proven damaging and unsustainable and was replaced by conservation agriculture (CA) using no-till systems following the ‘dustbowls’ incident in the USA. However, the continuous practice of CA has brought new soil and agronomic challenges, such as soil water repellence, soil pH and nutrient stratification, subsoil acidity, compaction and herbicide resistance, threatening the sustainability of broadacre cropping again. In recent years, one-off deep strategic tillage (ST) has brought attention and shown promise in overcoming the challenges imposed by CA and improving the sustainability of broadacre cropping. Deep ST approaches are now available for applying and incorporating soil amendments such as agricultural lime to a targeted depth while treating soil water repellence and loosening the compacted subsoil. Some ST practices have also been proven to manage weed seed banks and decrease the demand for herbicide applications. Many farmers in southern Australia have adopted ST to address the above-mentioned soil and agronomic challenges. When ST is practised, care should be taken in selecting the right timing, soil conditions and depth of tillage for successful outcomes. Once ST is implemented, reestablishing CA would ensure the longevity of the benefits of ST

Topsoil Evaporation in Water Repellent Soil Affected by Tillage and Claying: Preliminary Case-study Results

Soil water repellence represents one of the major soil constraints to broad-acre agriculture in southern Australia. Topsoil wettability is significantly reduced by the presence of hydrophobic organic compounds, resulting in poor seed germination, early plant establishment and ultimately lower yields. Soil mechanical disturbance (tillage) in combination or not with the addition of clay-rich subsoil (e.g. clay spreading) have been successfully adopted in the Australian broad-acre agriculture for the amelioration of water repellent sandy soils

Topsoil Evaporation in Water Repellent Soil Affected by Tillage and Claying: Preliminary Case-study Results

Soil water repellence represents one of the major soil constraints to broad-acre agriculture in southern Australia. Topsoil wettability is significantly reduced by the presence of hydrophobic organic compounds, resulting in poor seed germination, early plant establishment and ultimately lower yields. Soil mechanical disturbance (tillage) in combination or not with the addition of clay-rich subsoil (e.g. clay spreading) have been successfully adopted in the Australian broad-acre agriculture for the amelioration of water repellent sandy soils

Dynamics of water use by wheat and canola crops in compacted, acidic sands treated with deep tillage and lime

Incorporation of agricultural lime by ‘strategic deep tillage’ is one of the quickest methods for managing subsurface soil acidity. Such soil amelioration practice decreases soil resistance by removing compaction and increases soil pH, which allows deep penetration of crop roots, and hence increases the acquisition of soil water from deeper in the soil. As a result of improved soil physical and chemical properties, crop yield also increases and so does the water use efficiency (WUE). Under broadacre cropping conditions, WUE is generally estimated from crop yield and weather data; actual measurement of soil water uptake can lead to more accurate interpretation of results, especially where soil profiles are ameliorated to varying degrees

Soil Quality: 4 Soil Acidity

The Soil Quality ebook series is a resource for farmers, agricultural professionals and students. Experts from their fields share current knowledge and best practice techniques in layers of information, allowing readers to choose the level of detail they require. Book 4 Soil Acidity explains the causes and implications of soil acidity in broadacre agriculture. Diagnosis and management guidelines are supported by current research results and farmer case studies.https://library.dpird.wa.gov.au/sq_ebooks/1003/thumbnail.jp

Variable aluminium toxicity and root distribution in acidic soil profiles

Subsoil acidity currently affects two thirds of the arable soils in the WA wheatbelt. At acidic soil pH, aluminium (Al) is solubilised from the solid phase into soil solution, creating a direct and localised toxicity to plant roots. Aluminium toxicity to plant roots constrains crop productivity by reducing root proliferation through soil, and inhibiting the capacity of roots to tolerate other constraints, such as compaction. Ongoing acidification of the subsoil is a direct artefact of the productive farming systems that are required to feed our world’s growing appetite for grain and livestock products

Strategic tillage in Australian conservation agricultural systems to address soil constraints: How does it impact weed management?

In the conservation agricultural systems practised in Australia, cultivation is not commonly utilised for the purpose of weed control. However, occasional use of tillage (strategic tillage) is implemented every few years for soil amelioration, to address constraints such as acidity, water repellence or soil compaction. Depending on the tillage method, the soil amelioration process buries or disturbs the topsoil. The act of amelioration also changes the soil physical and chemical properties and affects crop growth. While these strategic tillage practices are not usually applied for weed control, they are likely to have an impact on weed seedbank burial, which will in turn affect seed dormancy and seedbank depletion. Strategic tillage impacts on seed burial and soil characteristics will also affect weed emergence, plant survival, competitive ability of weeds against the crop and efficiency of soil applied preemergent herbicides. If growers understand the impacts of soil amelioration on weed demography, they can more effectively plan management strategies to apply following the strategic tillage practice. Weed seed burial resulting from a full soil inversion is understood, but for many soil tillage implements, more data is needed on the extent of soil mixing, burial of topsoil and the weed seedbank, physical control of existing weeds and stimulation of emergence following the tillage event. Within the agronomic system, there is no research on optimal timing for a tillage event within the year. There are multiple studies to indicate that strategic tillage can reduce weed density, but in most studies, the weed density increases in subsequent years. This indicates that more research is required on the interaction of amelioration and weed ecology, and optimal weed management strategies following a strategic tillage event to maintain weeds at low densities. However, this review also highlights that, where the impacts of soil amelioration are understood, existing data on weed ecology can be applied to potentially determine impacts of amelioration on weed growth