Extended Fallow
Lengthening fallow periods between crops to save water and improve soil
Overview
Extended fallow as a program measure is relatively new; GSAs are conducting pilots. It is common practice to have a short (< 2 years) fallow period in between when a mature vineyard is removed and a replacement vineyard is planted. Lengthening the duration of this fallow period beyond 2 years can offer numerous agronomic benefits while also saving water.
Water Savings
No irrigation (winegrapes) or reduced irrigation of low water use interim crops.
Other Benefits
Soil rest and/or opportunities to improve soil quality through amendments, treatments, cover crops, pest and disease control, time to plan and design new crop installation.
Factors to Consider
Crop type, severity of issues that the fallow can help correct, cost (changes in market prices that might influence length of fallow). Other GSAs in California are piloting extended fallow programs.
Extended Fallow Quick Facts — Perennial Crops
Advantages to extending the fallow period include:
- Pest and disease control — Serious vineyard pests like the Vine Mealybug can only be eradicated from a site with an extended fallow period.
- Soil recovery — Irrigated soils in the basin are salinized over time from the addition of salts with the irrigation water, and the extended fallow period allows for leaching of salts to occur with rainfall.
- Time to design, plan and prepare field — Additional time for site preparation and crop planning.
Challenges of extended fallow include:
- Erosion — Any required tillage should be carried out in a manner that minimizes the risk of runoff and erosion. The use of green manure crops may be beneficial to help minimize erosion risk while providing added benefits such as nitrogen fixation and nutrient retention.
- Weed growth — Weeds such as Yellow Starthistle and Field Bindweed may require ongoing control to prevent them from becoming more established during the fallow period.
Resources
Dry Farming and Water-Limited Cropping Systems — Summary
| Measure | Description | Water Savings Benefits | Other Benefits | Factors to Consider |
|---|---|---|---|---|
| Dry Farming | Farming without irrigation in semi-arid conditions. | No irrigation used. | No cost and labor associated with irrigation systems and groundwater use. Dry farming systems are often compatible with other alternative management systems such as regenerative, biodynamic, etc. in areas with sufficient rainfall. Potential for differentiation in the marketplace for both fruit and wine. | Annual precipitation, soil type and depth, topography, water accessibility; proximity to depleted groundwater, market, economic feasibility. |
| Extended Fallow | Lengthening the fallow period between removal and replant of a perennial crop. | No irrigation (winegrapes) or reduced irrigation of low water use interim crops. | Soil rest and/or opportunities to improve soil quality through amendments, treatments, cover crops, pest and disease control, time to plan and design new crop installation. | Crop type, severity of issues that the fallow can help correct, cost (changes in market prices that might influence length of fallow). |