Irrigation-management decision system (IMDS) for vineyards (Regions VI and VII of Chile)

摘要

In Chile, most barriers to more efficient irrigation management are associated with poor estimations of vineyard water use. Crop coefficients reported in the literature are not adapted to the local conditions. Moreover, growers generally use non-quantitative observations of canopy and soil conditions to determine whether water availability is low or not. Current approaches are unhkely to optimize irrigation timing and the amount of irrigation application. For this reason, in 1998, the Research and Extension Centre for Irrigation and Agroclimatology (CITRA) established an irrigation-management decision system (IMDS) for grape-growers in Regions VI and VII of Chile. This system requires input data on: soil properties (texture, field capacity, wiltingpoint, bulk density, wetting pattern, and effective rooting depth); weather variables (air temperature, relative humidity, wind speed, solar radiation, and precipitation); and vineyard characteristics (cultivars, vine vigour, irrigation system, and yieldtarget). Soil characteristics are used to calculate the available waterholding capacity, and weather data are used to compute vine evapotranspiration (ET^i^e). Because of the uncertainty of the crop coefficient values (Kc), the irrigation schedule is designed using soil-water content measurements in the effective rooting depth (ERD) for each growing season. Using the weather information in combination with soil-water measurements, Kc values are calibrated for each specific soil, climate, and vineyard condition, according to yield and quality targets. The EXican then be used to estimate irrigation needs on a daily basis. Once a general irrigation plan is in place for a given vineyard, more refinements can be made to manage zones differentially within avineyard.