# Vineyards and Apple and Olive Orchards, Chile

## Science Center Objects

Landsat has been instrumental in helping Chile estimate water demand. The country often faces drought conditions, and although some level of water supply is guaranteed from dams and reservoirs, seasonal supply is uncertain. Agricultural production is a large enterprise in Chile, and water shortages create uncertainty in agricultural production as well as economic growth and sustainability. Landsat imagery allows the country to estimate seasonal demand and match it against seasonal supply to achieve optimal irrigation practices for maximum production.

Landsat has been instrumental in helping Chile estimate water demand. The country often faces drought conditions, and although some level of water supply is guaranteed from dams and reservoirs, seasonal supply is uncertain. Agricultural production is a large enterprise in Chile, and water shortages create uncertainty in agricultural production as well as economic growth and sustainability. Landsat imagery allows the country to estimate seasonal demand and match it against seasonal supply to achieve optimal irrigation practices for maximum production. Landsat data and the METRIC model are being used in Chile for the estimation of consumptive water use. Using this information, water budgets are created and a more accurate estimate of water demand is calculated. In conjunction with METRIC, Landsat data are being used to estimate evapotranspiration and the crop coefficient for olive and apple tree orchards as well as vineyards (figs. 1 and 2). The output is used to develop water-management strategies on farms and at the regional level.

Landsat data became available at no cost in 2008. This has had a significant effect on the extent of its applications, although its use in Chile by Dr. Samuel Ortega of the Universidad de Talca started a few years earlier, using only a few purchased scenes to launch the current research. Since 2005, over 500,000 acres of olive and apple orchards as well as vineyards have been surveyed using Landsat and METRIC to estimate regional and local consumptive use for water budgets. Landsat imagery allows adjusting the application of water on each vineyard based on water requirements for a specific production outcome. A Landsat-based recommendation of delaying the start of irrigation from September to November has saved up to two months of irrigation water in some regions for producers enacting the practice. While using Landsat imagery to help identify the most accurate crop water requirement on private agricultural lands at the farm level, the following benefits have been observed:

• A $80/acre cost savings in energy used for irrigation on over 3,700 acres of olive orchards per year, • A 30 percent to 60 percent reduction in the amount of water applied on grapevines on 6,000 acres, and • An increase in grape quality between 30–35 percent. Evapotranspiration mapping of a drip-irrigated vineyard in Chile using images from Landsat 7 ETM+. Courtesy of Universidad de Talca. Crop coefficient mapping of a drip-irrigated vineyard in Chile using images from Landsat 7 ETM+. Courtesy of Universidad de Talca. Water budgets allow for the control of water application and adjustment of the crop water coefficient. This enables strategic planning for water application and yields higher quality grapes. Although higher quality grapes correlate with lower production amounts, the profits are offset by higher wine quality and a higher price per bottle. An increase from$1.00 to \$20.00 per bottle from water-application adjustment has been observed in some of the plots where Landsat imagery is used to adjust irrigation practices. Additionally, a decrease in irrigation energy cost, as a result of a smaller amount of water applied, contributes to the overall increase in profit.

As evident by the examples provided, Chile has been able to use Landsat imagery to improve agricultural production and use a scarce resource more efficiently. Government officials in Chile seek consumptive-use information from Landsat and METRIC to help drive informative policy decisions regarding water supply, storage, and allocation. The long term goal from using this technology would be to establish a water market. Although some challenges exist with current Landsat output, due to issues such as cloud cover and 16-day repeat coverage which limit the amount and quality of usable data, Landsat remains the main source of moderate resolution imagery with thermal data used for work in water resources ongoing in Chile (Samuel Ortega, Universidad de Talca, oral commun. and written commun., 2013).

Reference:

Dr. Samuel Ortega-Farias, Professor Titular, Department of Agricultural Production, University de Talca, Santiago, Chile.

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