WSET Diploma D1 Exercises (Managing Nutrients and Water)

Answer

Cover crops are specifically cultivated or grown plants that benefit vineyards.

Cover crops help suppress weed growth, thereby reducing the need for chemical herbicides. They enhance soil structure, increase biological activity, and boost biodiversity, all of which contribute to healthier soil and vines. Additionally, these crops compete with vines for nutrients and water in fertile areas, helping to moderate excessive water and nutrient supply. They also stabilize the soil to prevent erosion and create a more manageable surface for vineyard operations.

However, there are some disadvantages. In poor soils or dry environments, cover crops can excessively reduce vine vigor. They also pose maintenance challenges due to mowing difficulties and the risk of creating slippery conditions when wet in steep vineyards.

Grading Criteria

• Cover Crop Definition
  • For defining cover crops as plants specifically cultivated or grown to benefit vineyards, you get 1 point.
• Advantages
  • For explaining their role in suppressing weed growth, you get 1 point.
  • For highlighting that this reduces the need for chemical herbicides, you get 1 point.
  • For mentioning their contribution to soil structure, biological activity, and biodiversity, you get 1 point.
  • For explaining that cover crops help moderate water and nutrient supply by competing with the vine, you get 1 point.
  • For describing their role in stabilizing the soil to prevent erosion, you get 1 point.
  • For noting that they create a manageable surface for vineyard operations, you get 1 point.
• Disadvantages
  • For mentioning that cover crops can excessively reduce vine vigor in poor soils or dry environments, you get 1 point.
  • For highlighting the maintenance challenges posed by mowing difficulties, you get 1 point.
  • For describing the risk of slippery conditions in steep vineyards, especially when wet, you get 1 point.

Answer

Grape growers use mulch for several reasons. Mulching involves spreading organic or inorganic materials onto the vineyard soil, primarily to suppress weed growth. Organic mulches, such as straw or bark chips, decompose over time and can eventually provide nutrients for the vines, making them especially beneficial in nutrient-poor vineyards. Additionally, mulch helps reduce water evaporation from the soil, which is particularly advantageous in dry climates. Moreover, it promotes soil biological activity and improves soil structure by increasing humus content. This method is chemical-free, making it suitable for organic and biodynamic viticulture.

Grading Criteria

• Premise
  • For the definition that mulching involves spreading organic or inorganic materials onto the vineyard soil, you get 1 point.
• Why grape growers use
  • For explaining that grape growers use mulch to suppress weed growth, you get 1 point.
  • For pointing out that grape growers use mulch in nutrient-poor vineyards, you get 1 point.
  • For the reason above that organic mulches decompose over time and can eventually provide nutrients for the vines, you get 1 point.
  • For pointing out that grape growers use mulch in dry climates, you get 1 point.
  • For the reason above that mulch helps reduce water evaporation from the soil, you get 1 point.
  • For pointing out that grape growers use mulch when they want to increasing humus content, you get 1 point.
  • For the statement that this promotes soil biological activity and improves soil structure, you get 1 point.
  • For pointing out that grape growers use mulch for organic and biodynamic viticulture, you get 1 point.
  • For the reason above that this method is chemical-free, you get 1 point.

Answer

Utilizing water-efficient irrigation systems, such as drip systems, can help save water economically. Drip systems can be further enhanced by closely monitoring the water uptake by the vines. Choosing drought-tolerant grape varieties, like Grenache, and appropriate rootstocks are also effective options for increasing water use efficiency. Another method is reducing evaporation from the soil by applying mulch. Removing weeds to reduce competition for water is also effective. Additionally, increasing humus levels in the soil by adding organic matter improves water retention. Encouraging vine roots to grow deeper into the soil allows them to access water from deeper layers.

Grading Criteria

• Utilizing irrigation system
  • For pointing out that utilizing water-efficient irrigation system can help save water economically, you get 1 point.
  • For explaining that drip irrigation systems can be optimized by closely monitoring the vine’s water uptake, resulting in more efficient water use, you get 1 point.
• Drought-tolerant grapes and rootstocks
  • For pointing out that choosing drought-tolerant grape varieties for efficient use of water, you get 1 point.
  • For pointing out that choosing appropriate rootstocks for increasing water use efficiency, you get 1 point.
• Reduce evaporation
  • For pointing out reducing evaporation from the soil by applying mulch, you get 1 point.
• Reduce competition
  • For pointing out removing weeds to reduce competition, you get 1 point.
• Water retention
  • For pointing out increasing humus levels in the soil for improves water retention, you get
  • For listing example to increase humus level such as adding organic matter, you get 1 point.
• Roots to grop deeper
  • For pointing out encouraging vine roots to grow deeper into the soil, you get 1 point.
  • For the reason above that this allows them to access water from deeper layers, you get 1 point.

Answer

Regulated deficit irrigation (RDI) is one of the irrigation technique where the water supply to a plant is intentionally reduced at specific growth stages, rather than providing a constant or full amount of water throughout the growing season. A dripper system is typically used to allow for precise control over the water application.

RDI is considered beneficial because a vine’s need for water fluctuates throughout its development stages. For instance, providing ample water in the spring stimulates the growth of a large leaf canopy, which helps support high grape yields. Conversely, applying moderate water stress between fruit set and véraison can restrict shoot growth, encouraging the development and maturation of the grapes. These practices ultimately contribute to improving the quality of the grapes.

Grading Criteria

• Definition
  • For explaining that RDI changes water supply intentionally during specific growth stages, you get 1 point.
  • For contrasting ordinal irrigation with providing a constant or full amount of water throughout the growing season, you get 1 point.
  • For mentioning the use of a dripper system to allow precise control over water application, you get 1 point.
• Advantages
  • For stating that a vine’s water requirements fluctuate throughout its growth cycle, you get 1 point.
  • For explaining that providing ample water in the spring promotes the development of a large leaf canopy, you get 1 point.
  • For stating that this large leaf canopy helps support high grape yields, you get 1 point.
  • For explaining that applying moderate water stress between fruit set and véraison restricts shoot growth, you get 1 point.
  • For stating that water stress encourages grape development and ripening, you get 1 point.
  • For concluding that these practices improve grape quality, you get 1 point.