Evaluating the Quality of Deep Tillage in Vineyard Development.

In establishing vineyards, deep tillage is an essential operation aimed at manipulating the native terroir of the site to engineer a hospitable root zone before planting vines. The objective of deep tillage is to create a specific size of root zone that embodies uniform soil physical conditions which will promote uniformity of vine growth and fruit ripening, both prerequisites for premium wine production.
Traditionally vineyard developers have relied on simple vertical tines (“shanks”) for this purpose. In the last two decades attachment of wings to a shank (“winged tine”) has been shown to improve the quality of deep tillage in clayey soils. More recently, tillage tools fitted with mechanically oscillated wings have appeared. Such tillage machinery systems (e.g. www.Soilworks.net) are now operating successfully in Australia and California and possibly elsewhere.
The dynamism of oscillating tillage tools provides opportunity for improving soil disruption by fine-tuning the operational mechanics such as varying wing numbers, shape, placement and oscillation rate. To evaluate benefits derived from these innovations, we need measurements that describe the quality of the end product of ripping in terms of soil attributes that affect vine growth.
We propose that the factors that primarily determine the quality of vineyard tillage are the size of the decompacted zone, the absolute strength of the decompacted soil, the uniformity of decompaction and the sustainability of the decompacted root zone. For some of these, ideal conditions can be defined such that the factors can be expressed as indices ranging between unity and zero or negative unity with unity indicating highest quality tillage, zero poor tillage and negative values representing compaction by the tillage tool.
We define these factors in quantitative terms, describe their application and give examples of comparative measurements on tillage sites.