Grapevine water relations and rooting depth in karstic soils.

Area of Science:

• Viticulture and Plant Physiology
• Environmental Science
• Soil Science

Background:

• Drought negatively impacts viticulture sustainability.
• Limited knowledge exists on grapevine water status and irrigation needs in limestone regions.
• Understanding water uptake is vital for managing vineyard irrigation.

Purpose of the Study:

• To monitor grapevine water status and soil relations in Istrian Malvasia on Karst red soil during a dry vintage.
• To evaluate water demand and uptake strategies in young and old vines under drought conditions.
• To investigate the influence of soil type on water resource utilization.

Main Methods:

• Monitoring plant and soil water relations in vineyards with varying vine ages and soil types.
• Analyzing oxygen isotope composition (δ18O) of rainfall, soil water, and xylem sap to track water sources.
• Measuring midday leaf water potentials to assess plant water status.

Main Results:

• Vines on karstic substrates utilize deep soil water, maintaining favorable water status despite drought.
• Grapevines approached but did not exceed severe water stress thresholds (leaf water potential >-1.3MPa).
• Root systems demonstrated flexible water uptake from both deep and shallow horizons, especially in stony soils.

Conclusions:

• Deep rooting in karstic soils ensures stable water sources for vines during summer droughts.
• Flexible root water uptake enhances vine resilience to drought and rapid recovery after rainfall.
• Findings offer insights into grapevine water needs and rooting depth on shallow karstic soils, informing sustainable irrigation practices.