An Evaluation of Brackish Water for Growing Nursery Crops under Hydroponic Conditions
The growth of afghan pine (Pinus eldarica), pistachio (Pistasia atlantica) asparagus (Asparagus officinales), iceplant (Lamprathus spectablis), portulaca (Portulaca grandifolia) and statice (Limonium sinuatum)was evaluated under different levels of brackish water using various methods of hydroponic culture. Rates of brackish water tested included a full strength (1X) brackish water solution made by copying the analysis of a water from Roswell, New Mexico. This water had an electrical conductivity (EC) of 24 mmohs/cm, and over 14,000 ppm total dissolved solids. The predominant ions were chloride, sodium and calcium. Dilution of the water were as follows, 0.75X, 0.50X, 0.25X, 0.125X and 0.06X. Hoagland’s complete nutrient solution (HCNS) was added to all test solutions and when used alone was the control treatment. In solid media tests all species, except pistachio, survived and grew under the highest concentration of brackish water. However, growth rate declined abruptly when brackish water levels exceeded 0.125X (iceplant, statice) 0.25X (pistachio, portulaca), or 0.50X (afghan pine, asparagus). The results are encouraging with the solid media and more work appears warranted.
In the liquid media tests (nutrient film technique and aerated nutrient solution) plant growth was sporatic and generally non thrifty in all brackish water plots. This was true even after seedling had been established in water or Hoagland’s solution and evidence of many healthy new roots was present. There were colonies of fungi and bacteria on the roots, but it was not determined whether these microorganism were pathogens causing the plant decline or whether they were opportunistic saprophytes responding to saline water induced root damage. It was concluded that the liquid methods offer little promise for nursery plant production.