COVER CROPS in South African Vineyards

COVER CROPS IN SOUTH AFRICAN VINEYARDS

different trials. Some trials were carried out to test the effect of no irrigation and drip irrigation. Details are given in the sections that describe those trials. The general schedule during the grapevine-growing season (September to February) was full-surface micro-sprinkler irrigation applied when approximately 60% of the plant-available water was depleted to replenish the soil to field water capacity. Trials of candidate cover-crop plants in open fields received 16 millimetres irrigation for the first ten weeks after sowing.Thereafter, winter rains were usually sufficient for their needs. In the Coastal region, the relatively high winter rainfall enables cultivation of a cover crop in non-irrigated or drip-irrigated vineyards. However, full- surface sprinkler irrigation is still recommended during the first weeks after sowing to reduce the risk of crop failure. Cultivar and management The trials at theARC Infruitec-Nietvoorbij research farm were mostly carried out in a vineyard of Chardonnay grafted on Richter 99.The vines were trained on a seven-strand double lengthened Perold trellis system. Evaluation of certain cover crops were performed in vineyards of Cabernet Sauvignon grafted on Richter 110, and trained on a double lengthened Perold trellis system.All grapevines at the research-farm trial sites were spaced 1.5 metres apart in rows spaced 2.75 metres apart. At Boschendal, a trial vineyard of Sauvignon blanc grafted on Richter 99 was used.The vines were trained on a Perold trellis system. Grapevines were spaced 1.2 metres apart in rows spaced 2.75 metres apart. Blaauwklippen trials were performed in Shiraz grafted on Millardet et de Grasset 101-14 (101-14 Mgt). Grapevines were trained on a five-strand Perold trellis system and were spaced 1.2 metres apart in rows spaced 2.5 metres apart. The Plaisir de Merle trial was performed in vineyard of Sauvignon blanc grafted on Richter 99.The vines were trained on a four-strand Perold trellis system and were spaced 1 metre apart in rows spaced 2. 5 metres apart. Where else do these results apply? The soils at the Coastal region sites are comparable to those of much of the wine- and table-grape plantings in the cooler regions of theWestern Cape.

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