South Africa Wine Research Projects

2. VITICULTURE RESEARCH NEW PROJECT

EVALUATION OF ORGANIC FERTILISERS ON SOIL QUALITY AND WINE GRAPE PERFORMANCE

SU-SS AH 24-01 Dr Ailsa Hardie-Pieters, Department of Soil Science, Stellenbosch University Start date: 2024

AIM AND INDUSTRY RELEVANCE: Wineries experience consumer pressure to produce wines from vineyards using organic fertilisers, which are perceived to be more sustainable and environmentally friendly. Synchronising organic- or mineral fertiliser nutrient availability with crop uptake requirement is important to ensure high nutrient use efficiency and optimum crop production. In South Africa, there is a notable scarcity of local scientific data on how organic fertilisers impact the production of wine grapes. The extent to which organic fertilisers can provide the necessary quantities of mineralised nitrogen in sync with grapevine demand is not well known. This study aims to fill this knowledge gap by comprehensively evaluating and comparing major types of organic fertilisers to conventional ones and their impact on soil quality and winegrape production. To initiate this study, a comprehensive literature study will be conducted, whereafter a field trial is planned. The field trial will occur in a commercial 12-year-old Chardonnay vineyard grafted on Ramsey on a farm in Robertson. The different applications will be manually applied over three years. Each plot’s soil chemical and physical properties will be measured and identified before the commencement of the study. During the first year of the study, controlled laboratory mineralisation will be conducted to compare the C, N & P mineralisation dynamics of locally available organic fertilisers. The different treatments are as follows: • Control (no compost or fertiliser) • Commercial granular fertiliser applied after harvest, bud burst, and fruit set based on vine vigour (max 40kg/ha) • Blood-based organic fertiliser • Pelletised chicken manure organic fertiliser • Plant- & animal waste compost When all the data have been gathered, a financial evaluation will be conducted to ensure cost/ benefit figures support the vineyard’s performance.

SOUTH AFRICA WINE RESEARCH 2024

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