IMPACT OF ANTIOXIDANTS AND COBALT ON GROWTH PERFORMANCE OF BROCCOLI PLANTS IRRIGATED BY DIFFERENT IRRIGATION SOURCES

Use of different irrigation sources e.g, agricultural drainage water becomes necessary to mitigate the expected water scarcity in the future. So, a field trial was implemented in a split split-plot design with three replicates aiming at evaluating the impact of three sources of irrigation water as main plots [normal irrigation water (freshwater), agricultural drainage water and a mixture between them], foliar application of two antioxidants [ascorbic acid and proline at a rate of 10.0 mM L-1 for both alone and volume of 500 L ha-1] as subplots and foliar application of cobalt as sub subplots [0.0 and 8.0 mg cobalt L-1 as cobalt sulphate solution (36%Co) at volume of 500 L ha-1] on the performance of broccoli plants. The obtained results showed that broccoli plants irrigated by normal water have a high performance and yield, while broccoli plants irrigated by mixture water came in the second order, whilst the lowest was realized with broccoli plants irrigated with agricultural drainage water alone. Foliar application of ascorbic acid was the superior treatment followed by proline and lately control treatment (without antioxidants).Also, foliar application of cobalt at rate of 8.0 mg cobalt L-1 came in the first order, while the second order went to plants untreated with cobalt (0.0 mg cobalt L-1). Generally the best performance and yield were recorded when broccoli plants were irrigated by normal irrigation water (fresh water) and sprayed with both ascorbic acid and cobalt. Taking into account that spraying broccoli plants with both antioxidants (ascorbic acid or proline) and cobalt together under irrigation by mixture water possessed better performance and yield than broccoli plants irrigated by normal water without foliar any application.