Effect of plant growth stimulants on yield, nutrient concentration of wheat shoot and some soil properties under salinity stress

The most soils of Khuzestan province are calcareous with different degrees of salinity, however, they play a significant role in the country agricultural production. One of the new methods to deal with environmental stresses is the use of plant growth stimulants. The aim of this study was to investigate the effect of application of growth stimulants on wheat yield components in saline soil, environmental and climatic conditions of Khuzestan province. Experiment was performed in three replications as randomized complete block design with soil salinity of 8 dS m-1 and water salinity of 3-4 dS m-1 under seven different treatments consisting of control, free amino acid, seaweed, seed treatment, humic acid, fulvic acid and combination in 2018 for two years. The use of seaweed, humic acid and amino acid caused a significant increase 30, 25 and 24 % of grain yield as compared to control treatment (p ≤0.05). The results of economic analysis showed a significant advantage of the humic acid application in increasing wheat yield (profit to cost ratio = 13.38). Application of plant growth stimulants on the macro and micro nutrients concentration in wheat leaves was not significant in almost all stages of plant growth compared to the control (p ≤0.05). In addition, the application of growth stimulants in calcareous soils of Khuzestan due to high soil buffering capacity did not have a significant effect on soil salinity, pH and sodium uptake ratio. Therefore, it is recommended that in wheat fields of Khuzestan province with saline and calcareous soils, in addition to basic fertilizers, humic acid be used as foliar application in two growth stages of tillering and booting to increase stress plant resistance and improve crop yield.