Livro das Actas - advid

Livro Actas
to carry out plowing between rows. The underground located drip irrigation can be regarded
as an alternative to aerial, in order to remedy or alleviate some of the drawbacks
cited.
The underground irrigation development came into use at about the decade of the sixties
of the last century in the U.S., but until the early eighties there was no increased interest
in this technique (Camp 1998). Since then, it has been used both in annual crops, mainly
vegetables, as permanent.
The underground irrigation, compared to other types of irrigation, often presented in
most crops several advantages, including the ability to achieve higher performance and
lower water consumption (Camp 1998, Ayars et al. 1999, in Romero et al. 2006). From
the following references, all included in the work of Romero et al. (2006), it appears
that several inherent operational characteristics of such irrigation contribute to increase
efficiency in the use of water, due to greater control of unwanted vegetation (Grattan et
al. 1988), reduction of soil evaporation (Hoffman and Martin 1993), greater root density
(Phene et al. 1991), high activity and root absorption (Martínez-Hernández et al. 1991),
negligible deep percolation of water and soluble salts below the root zone, negligible
runoff and high uniformity of application (Phene et al. 1993).
According to a review of deficit irrigation in fruit trees and vines, made by Ruiz-Sánchez
et al. (2010), the underground irrigation produced greater horizontal distribution of fine
roots and stimulated root growth deeper in the soil profile. Probably, this was the main
reason for the increased efficiency in water use achieved. However, one of the most commonly
cited disadvantages for use underground irrigation systems is the difficulty to monitor
irrigation development and control uniformity of water application (Camp 1998).
Ayars et al. (1999) observed that the use of underground irrigation, in different rotation
extensive horticultural crops, produced a significant increase in performance and efficiency
in water use. After 10 years of cultivation, the irrigation system was in good condition
after having applied the recommended maintenance.
Also Bidondo et al. (2010), comparing the underground with overground drip irrigation
on tomato surface, observed a trend of underground irrigation to present higher values
in all variables considered, although differences was not statistically significant, with
increased use of water from the first system over the second.
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