Salt concentration of The Nutrient Solution: Effects on Transpiration Rate of Soilless Colture

Main objective of the study was to verify the possibility of testing salt
concentration effects on transpiration rate over an entire cycle of a crop, by using
hydroponic lysimeters. The experiment was carried out in North - West of Sardinia
(Italy). In 1996, nine hydroponic cropping units (CU) were used to measure
transpired water and cotton (Gossypium hirsutum cv. ‘Ogosto’) was utilized as test
crop. Three salt concentration levels were obtained adding seawater to the nutrient
solution: control (0% of seawater, EC 3.0 mS cm-1, pH 7.1), S8 (8% of seawater, EC
7.7 mS cm-1, pH 6.7) and S16 (16% of seawater, EC 11.5 mS cm-1, pH 6.4). Results
indicate that cotton plants are able to develop and produce with 8% of added
seawater without differences with control treatment, as previously assessed by other
authors. High level of salt concentration reduced plant growth and productivity and
increased TAF (transpiration per unit of leaf area, mm d-1). The hydroponic
lysimetric system proved to be an effective tool to study the effects of water salinity
on water transpiration per unit of leaf area during the whole crop cycle and hence to
distinguish the effects of salinity on plant development from the effects on leaf
transpiration.