Deep inclusive tillage zones (DITZ), origins and applications.
Topsoil drying frequency can restrict root and biology function for food production as growing seasons become warmer, especially for the sandier soil types. The theoretical and known benefits of deep inclusive tillage in relatively narrow zones (about 400-700mm) by tines, plates, delvers or spading units are discussed. The techniques are similar to strip tillage methods developed for horticulture in Tasmania and the active strip inclusion system being developed in South Australia to deep till and minimise wind erosion risk on sandy soils. DITZ enables transfer of topsoil and ameliorants deeper into soil profiles with production constraints. The system also provides a strategy of incomplete paddock tillage, improving the efficiency of paddock treatment, yet not halving the yield and quality responses from the amelioration. There should usually be a net benefit in crop yield, quality and protection from damage by wind erosion. A greater width of equipment doing zone tillage (about 500mm wide zones) allowing a greater daily work rate in ha/day ameliorated. Some technicalities, problems and economics of such systems are presented and discussed.
Deep digger decision support system
Where soil amelioration has been proven to be economically beneficial the optimal solution between mitigation and amelioration is typically to ameliorate the entire constraint affected production system. However, in real world applications bound by budgets, and both labour and machinery hours there exists room for a compromise between low cost, low reward mitigation techniques, and high-cost high reward amelioration. Deep-digger is an input-based calculator to help choose investment use for optimum financial return at a farm or paddock scale.
We hope these concepts will help sustain food production from agricultural soils in southern Australia (parts of WA, SA and Victoria) especially in lower rainfall zones.