Chapter 12

Irrigation Scheduling of Grapevines

(book excerpts)

Good irrigation management is required for efficient and profitable use of water for irrigating the vineyard. A major part of any irrigation management program is the decision-making process for determining irrigation dates and/or how much water should be applied to the grapevines for each irrigation. This decision-making process is referred to as irrigation scheduling. To ensure that the vines are neither over, nor under watered requires constant monitoring of a number of factors including weather conditions, the amount of water stored in the soil from winter rains, the stage of development of the vines and the vineyard, the soil type(s), the irrigation system type, and its efficiency. Irrigation scheduling, which determines the time and amount of water to apply is usually based on four methods: 1) monitoring soil moisture levels by hand or with various instruments, 2) measuring plant-water status, 3) evapotranspiration-based, and 4) a water balance method based on the estimated crop water use rate and soil water storage. Many of these techniques are proven and have been in use for years for growing wine grapes. In reality, irrigation scheduling is most often a combination of the three basic techniques. The benefits of irrigation scheduling are widespread including cost efficiencies on electricity, water, labor, soil health, nutrient retention, and minimizing any detrimental environmental side effects such as nutrient leaching. Not adhering to an irrigation schedule may contribute to poor vine balance, excessive or poor vigor, decreased berry set, early berry dehydration, nutritional imbalances, and inconsistent yield and quality of fruit.

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Within This Chapter: Irrigation Scheduling of Grapevines

  • Introduction to Irrigation Scheduling of Grapevines
  • Soil-based Scheduling Methods
  • Hand Feel Method
  • Neutron Probes
  • Di-Electric Soil Moisture Sensors
  • Gypsum Blocks
  • Granular Matrix Sensors
  • Tensiometers
  • Neutron Probes
  • Advantages
  • Disadvantage
  • Principles of Operation
  • Placement of Monitoring Sites
  • Installation
  • Readings
  • Maintenance
  • Di-Electric Soil Moisture Sensors
  • Advantages
  • Disadvantage
  • Time Domain Reflectometry (TDR)
  • Frequency Domain Reflectometry (FDR)
  • Gypsum Blocks
  • Advantages
  • Disadvantage
  • Principles of Operation
  • Placement of Monitoring Sites
  • Installation
  • Readings
  • Maintenance
  • Granular Matrix Sensors
  • Advantages
  • Disadvantage
  • Principles of Operation
  • Placement of Monitoring Sites
  • Installation
  • Readings
  • Maintenance
  • Tensiometer
  • Advantages
  • Disadvantage
  • Principles of Operation
  • Placement of Monitoring Sites
  • Installation
  • Readings
  • Maintenance
  • Plant-based Scheduling Methods
  • Monitoring Visual Appearance of Vines
  • Pressure Chamber
  • Operation and Use of the Pressure Chamber
  • Timing
  • Vine and Leaf Selection
  • Evapotranspiration-based Scheduling Method
  • Determining Crop Evapotranspiration
  • Using real-time climatic data
  • Using historical evapotranspiration data
  • Using data from an evapotranspiration pan
  • Using a Bellani Plate Atmometer
  • Crop Coefficient (Kc)
  • Determining a Grapevine Crop Coefficient
  • Steps in Calculating Estimated Water Use
  • Water Budget Scheduling Method
  • Vineyard Weather Stations
  • References