Technical Yearbook 2024

FIGURE 1. Levels of (A) soil K and (B) Na in the LOR2 shallow sand experimental plot and control, respectively, in September 2019.

Similar results were reported for soils in a pot study. 3 Taking above mentioned into consideration, the in-field fractional use (augmentation) of winery wastewater with raw water for vineyard irrigation at the LOR2 experimental plot had to be terminated at the end of the 2018/19 season to prevent further damage to the grapevines. It is well known that irrigation with saline water can have a detrimental effect on grapevines due to accumulation of elements within the grapevine. Given the substantial amounts of elements applied via the in-field fractional use (augmentation) of winery wastewater with raw water for vineyard irrigation in the Lower Olifants River region, together with the low mean annual rainfall, 2 the objective of this study was to make an assessment of the below- and above-ground chemical status of the grapevines growing in the Lower Olifants River region. The termination

of the fractional use (augmentation) of winery wastewater with raw water for vineyard irrigation at the LOR2 experimental plot and the irrigation thereof for two years with raw water according to the producer’s schedule gave the opportunity to assess the permanent wood structure at the end of the study to give an indication

plots were irrigated using the in-field fractional use (augmentation) of winery wastewater with raw water for vineyard irrigation from the 2017/18 to 2020/21 seasons. Soil samples were taken from the 0 - 30 cm, 30 - 60 cm and 60 - 90 cm layers in September 2019 at the LOR2 plot. Samples were analysed as discussed previously. 2 Each of the selected vineyards had an experiment plot that was or had been irrigated with winery wastewater and this was compared to the rest of the surrounding vineyard block which acted as the control. Soil profile pits were dug at the LOR2 shallow sand experiment plot and control in September 2019. The soil was removed carefully from the profile pit and placed onto a sieve. Roots were separated from the soil and placed into bags. Samples were collected in a similar way at the LOR1 experimental plot and control in May 2021. The excavated roots

of the recovery, if any, in terms of element accumulation in the permanent wood parts. Methods Details of the plot selection,

augmentation, climatic conditions, irrigation application, water quality, nutrient load and soil responses were given previously. 2 Briefly, there was a loamy sand (C1) and sandy clay loam (C2) experimental plot in the Coastal region, a sandy loam (BR1) and sandy clay loam (BR2) experimental plot in the Breede River region, as well as a deep sand (LOR1) and shallow sand (LOR2) experimental plot in the Lower Olifants River. Experimental

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TECHNICAL YEARBOOK 2024