Abstract
Subirrigation is an alternative irrigation method for greenhouse crops. Lack of leaching poses the problem of high salt buildup in the root zone. The objective of this study was to determine the effects of saline irrigation water on a greenhouse crop when used in a subirrigation system. New Guinea impatiens were grown in subirrigation trays using 8 Mol. ni'3 N and 0 to 18 Mol. M-3 NaCl + CaCl. Growth decreased with increasing salt concentration. Optimum growth was noted at 0 and 2 Mol. M-3 salts. Growing medium electrical conductivity was highest in the top compared to middle and bottom layers of the root zone. Experiment 2 compared salt tolerance of two cultivars. Growth was greatest at the 0 to 4 Mol. M-3 level, and reduced at levels greater than 6 Mol. M-3 for both cultivars. Root weight was highest and lowest in the middle and top layer of the root zone, respectively. Plants were grown under the same conditions in the third experiment. A quality rating determined that 'Illusion' was salable up to 4 mol . M-3 salts, while 'Blazon' was Plants were grown under the same conditions in the third experiment. A quality rating determined that 'Illusion' was salable up to 4 mol- m-3 salts, while 'Blazon' was only salable at the 0 mol . M-3 level. Plants were leached six times after the quality evaluation. Leachate EC increased up to the second leach then decreased with subsequent Teachings. At the first and second leach, EC of the growing medium decreased in the top layer and increased slightly in the middle and bottom layers. In the final experiment, two leaching fractions and leach times were compared. Complete nutritional analysis of media was conducted. Salts in the 8 Mol. m7 3 treatment appeared to be unaffected by Teachings in all layers of the root zone. By the final leach, middle and bottom layers were slightly higher than the pre-leach level in the 0 and 4 mol rd3 treatments while the top layer had decreased slightly. Plants were also placed in two post production environments and monitored for loss of turgidity after the first, second and sixth leach. Water deficit was compared and no differences were observed between the two.
Todd, Nancy Morgan (1996). The response of New Guinea impatiens to varying salinity levels in a subirrigation system. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1996 -THESIS -T63.