PREDICTING THE ROLE OF ANTIOXIDANTS AND IRRIGATION ON SUNFLOWER YIELD GROWN UNDER SALINE CONDITIONS

摘要

A field experiment was executed to study the influence of salinity, antioxidant application and cultivars on plant yield. Prediction equations were developed and used to predict sunflower yield under two levels of soil salinity(4.7dSm{sup}(-1) and 12.8dSm{sup}(-1)) in addition to application of three types of antioxidants ( ascorbic, salicylic and oxalic acids ). Also models were used to predict sunflower yield when increasing the concentration of antioxidants up to 300 ppm. Furthermore models were used to reduce the harm effect of salinity and improve sunflower potential yield by increasing the amount of irrigation water by 10%, reducing soil pH by 0.3 through applying organic manure either using the same amount of irrigation water or conserving some. The results showed that sunflower yield was highly reduced under saline soil, although spraying plants with antioxidants especially oxalic acid was helpful in improving plant yield but was still lower than optimum. Modeling also proved that increasing the amount of irrigation resulted in yield improvement reaching 86.9% under high soil salinity level. Also, modeling revealed that reducing soil pH under high salinity level improved sunflower yield when using oxalic acid by 57.14% While on limiting irrigation by 343 and 340 m{sup}3/fed and reducing soil pH under saline condition gave the most yield improvement when using ascorbic acid. Therefore it is recommended to spray sunflower plants with oxalic acid to relief salinity stress either under abundant amount of irrigation or reducing pH without an increase in the amount of water. Furthermore under deficit irrigation, spraying plants with ascorbic acid is preferable under saline soil and reduced pH.