Why Rip

The success of establishing permanent crops in a commercial venture relies on the basic steps of understanding the soils and how to treat the before planting. Ripping should produce a homogeneous, uniform planting root zone. In order to achieve a uniform root zone, ripping must be carried out continuously along the future plant row.

"Why Rip" by Dr. Alfred Cass

The importance of ripping as an essential component of site preparation in establishing vineyards focuses attention on the need to routinely evaluate the quality of ripping. The quality of ripping largely reflects the future quality of the root systems of the vines.

Several numerical parameters are available for judging the effectiveness of ripping:

• volume of soil decompacted (size of the root zone)
• extent of decompaction (the strength of the soil in the root zone)
• sustainability of decompaction (persistence of favorable root growth conditions)

Site preparation is a fundamental activity in establishing vineyards. The type of work and attention to detail in site preparation has a profound impact on the future success of the vineyard. In particular, soil tillage by ripping is an intrinsic component of site preparation and a critical part of other preparatory activities including amendment addition and row configuration. The basic aim of soil "ripping" in establishing vineyards growth and performance of the vines to sustain fruit production for as many years as possible. Achieving this objective involves considerations relating to promoting root growth, creating optimum root volume and enhancing sustainability of the vineyard.

Each of these concepts has considerable ramifications that will affect fruit production capacity and quality and future management of the vineyard. Consequently, the effect of any particular ripping operation needs to be closely tied to the overall business plan for the vineyard and the design of the vineyard being established.

Sustainability of Ripping Improvement
Sustainability of decompaction created by ripping is usually addressed by application of amendments such as gypsum and compost and incorporating them into the ripped profile. Sustainability of ripping can also be promoted by adopting subsequent good soil structure. These practices stabilize and protect the beneficial soil aggregates created by ripping against the tendency of wetting and drying and vineyard traffic to recompact the soil over time. Consequently, the sustainability of the physical improvements to soil properties created by ripping can really only be measured as a function of time which we could not do here.

However, soil moisture at the time of ripping can have an effect on sustainability. Dry soil behaves as a brittle solid and fractures explosively to produce large hard clods and fine powder. If soils are ripped when dry, much of the soil will fracture into fine aggregates (<1 mm, <0.04 inch) that will rapidly coalesce (weld together) when wetted, reducing the sustainability of the ripping. Soils ripped too wet will not fracture optimally either since they are plastic enough to tend to flow past the ripping tool and may compact in the process.

Ripping at the correct subsoil moisture content is critical for effective decompation of all soils with significant clay content (sandy clay loams through to clays). The optimum water content is called the (Lower) Plastic Limit. It is the water content at which the soil mechanical behavior changes from brittle to plastic. At this water content the soil will fracture correctly to yield moderate (5 to 25mm diameter) fragments necessary for optimum root penetration. The texture of soil affects the Plastic Limit water content. Sandy soils have quite low Plastic Limit water contents, generally around 10% or less and loamy soils 10 to 20% volumetric water content.

Other factors which have a bearing on sustainability are the weight of machinery used for ripping and the number of passes necessary o create acceptable conditions. Generally heavier machinery damages soil structure more than lighter machinery, creating more dust and powder. The more passes needed to complete the work, the greater the structural damage and the greater the chance of creating dust and powder.