Technical Yearbook 2023

Visual vigour above the soil surface is a direct reflection of the performance of the roots below the soil surface. The maintenance of a healthy root zone and good root distribution are thus imperative (photo 1).

PHOTO 1. Example of good root distribution.

PHOTO 2. Vine roots confined in the planting hole.

In this article, the most common compaction problems in vineyards are briefly discussed, namely: • Planting hole compaction. • Recompaction due to cultivation after soil preparation. • Surface compaction/crust formation. • Tractor wheel compaction. • Root pruning. Planting hole compaction Planting hole compaction (photo 2) is a serious yet widespread problem in vineyards and is caused by incorrect planting methods and timing. Unfortunately poor planning and contractor teams racing against time are often the main causes of this problem. In such cases the young vines are planted when the soils are too wet and the smearing action of a spade results in smooth planting hole walls through which roots cannot penetrate. It is compounded by the lever action of a spade to scoop soil out of the planting hole, which leads to compaction of the side walls in the planting hole. Furthermore the young vines are sometimes positioned against the side of the (smeared/compacted) planting hole

and tamped down (photos 3 and 4) instead of placing the vine in the middle of the planting hole on heaped loose soil (the so-called mole-hill method). The planting holes are then simply filled with soil, while the best practice is rather to use a fork to break in the compacted side walls around the young vine. The result of this incorrect planting technique is that grapevine roots remain confined in the planting holes and are unable to grow out and utilise the soil volume optimally. The growth of such young vines is severely impeded and the vines cannot perform as desired. To alleviate this compaction problem, a cultivation action must take place between the tractor wheel and the vine row. The soil should be dry enough to enable loosening of compacted planting hole walls, but not so dry that clods form, and the toe length of the implement should be at least 40 - 60 cm long. A paraplough (photos 5 and 6) or ripper with swing wings on the back is the designated implement choice in this case if the soil properties allow. Depending on the severity of the compaction and growth of the vines, the action should be performed on

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TECHNICAL YEARBOOK 2023