Interactive Effects of Encapsalt Bio-Stimulant and Salinity Stress On Growth and General Quality of Ryegrass (Lolium prenne L.).

Perennial ryegrass (Lolium perenne L.) cultivar Galileo was studied hydroponically using Hoagland solution No. 1 in a greenhouse to evaluate its growth responses in terms of shoot and root lengths, shoot (clippings) fresh and dry matter (DM) weights, and grass general quality under two levels (EC = 8 and 12 dS m^-1) of sodium chloride (NaCl) salinity stress at various (0, 30, 60, 120 ml/93 m^-2 as control, ½ the recommended rate, recommended rate, and double the recommended rate, respectively) Encapsalt Bio-stimulant application rates. A randomized complete block design with 4 replications was used in this study. Shoot and root lengths, shoots (clippings) fresh and DM weights were determined weekly. After the fresh weight determination, shoots were oven-dried at 65º C and DM weights recorded. At the last harvest, roots were also harvested and fresh weights were determined, then oven-dried at 65º C and DM weights were recorded. The grass general quality was also evaluated every other day or weekly at each salinity stress level and at each bio-stimulant application rate. The results showed the shoot lengths and weights of ryegrass were stimulated under any level of Encapsalt application rate at the lower (8 dS m^-1) level of salinity. However, at the higher level of salinity (12 dS m^-1), the beneficial effect of Encapsalt was inconsistent. There was no difference on the effect of the compound between the ½ the recommended rate and the recommended rate treatments on the shoot lengths and weights of ryegrass. Doubling the recommended rate of the product resulted in insignificant increase in shoot length compared to the untreated plants. Encapsalt had a significant effect on enhancing root lengths and weights at the lower level of salinity, but did not have any beneficial effect on the root length of the grasses under the high level of salinity stress. The grass general quality followed essentially the same pattern as the shoot dry weights. Ryegrass general quality was more beneficially affected under the ½ the recommended rate or the recommended rate of the Encapsalt with no difference under these two application rates. These application rates of the product changed the unacceptable quality scores of 5 and 4.5 to acceptable scores of 6.5 and 5.5, respectively. Doubling the recommended application rate of the product did not have any significant beneficial effect on grass quality, especially at the higher (12 dS m^-1) level of salinity. Based on the results of this study, Encapsalt bio-stimulant generally exhibited a significant beneficial effect on ryegrass growth under salinity stress condition.