Physiological response of lupine and associated weeds grown at salt-affected soil to α-tocopherol and hoeing treatments

About 900.000 ha of Egypt's agricultural lands are suffering from salinity build-up problem. Therefore, two field experiments were conducted in split-split plot design with four replications to study alpha-tocopherols foliar application with 100 and 200 ppm and hand hoeing (two and three hand hoeing, plus unweeded) and their interactive effects on growth, osmoprotectants, mineral contents, seed yield, yield components, and nutritive value of the lupine plants and its associated weeds grown under salt-affected soil at 1.30, 3.20 and 4.23 dS m(-1). Three hand hoeing treatment achieved the highest weed depression expressed in the lowest number and dry matter of broadleaved, narrow-leaved and total weeds, and reduction % in dry matter were 80.75, 78.25 and 79.26 % compared with unweeded, respectively. Salinity stress significantly decreased total chlorophyll content, leaf area index and plant dry weight, while alpha-tocopherol and hoeing increased in all previous traits relative to corresponding controls. Lupine seed yield, yield components, and oils, carbohydrates, proteins, carotenoids and alkaloids in the yielded seeds were significantly reduced by increasing salinity levels, meanwhile hoeing and alpha-tocopherol treatments improved them. Total essential amino acids were decreased by increasing salinity levels and increased by increasing alpha-tocopherol concentrations and number of hoeing treatments. It could be concluded that alpha-tocopherol especially at 200 ppm partially alleviated the harmful effects of salinity stress on the growth of lupine plants and nutritive value of the yielded seeds. Three hand hoeing treatment was the optimum and safe method in controlling weeds associated with lupine plant grown under salinity stress.