Materials and Methods

The experiments were carried out, between 1992 and 1998, at CIHEAM - Mediterranean Agronomic Institute (Bari, Italy), in the frame of a long-term experiment to study the crop response to soil salinity. Species behaviour of the species in saline environment was analyzed in previous studies by van Hoorn et al. (1993) and by Katerji et al. (1996, 1997, 1998a and b). The experimental data in this paper synthesize the observations obtained on the control treatments that were kept in well-watered condition with fresh water. Such a synthesis was never approached before. The Bari climate is Mediterranean. It is characterized by warm dry summers, with maximum air temperature sometimes higher than 40°C, and minimum relative humidity often less than 20%.

For each species, the set-up consisted of 10 cylindrical lysimeters of reinforced fibre glass with an internal diameter of 1.2 m and a depth of 1.2 m. A layer of coarse sand and gravel, 0.10 m thick, was overlain by a repacked soil profile of 1 m. At the bottom of the lysimeter, a pipe serving as a drainage outlet connected the lysimeter to a drainage reservoir. The set-up was covered at a height of 4 m by a sheet of transparent plastic. This sheeting excluded any rain, but attenuated the solar radiation up to 10 %. This maximum value was derived from radiation measurements taken above and below the sheeting, at different hours and seasons. A 5-lysimeter block was filled with loam, and a second block with clay. Table 1 presents physical properties of the soil after filling the lysimeters. The lysimeters were irrigated with fresh water in order to maintain well-watered conditions during the whole crop cycle.

Table 1. Soil properties

Soil type

(%) 2 ^50 |im

ral parts > 50|im

CaCÜ3 (%)

% W (v pF 2.0

ater V) pF 4.2

Bulk density (kg dm-3)

loam

0 0

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