Effect of foliar and soil potassium fertilisation on wheat yield and severity of Septoria tritici blotch

摘要

Field research was undertaken to investigate the effects of potassium K2SO4 (36% K) as a foliar spray and/or soil application on grain yield, 1000-grain weight and severity of Septoria tritici blotch on wheat during 1998 and 1999. Two Syrian bread wheat cultivars (Bohuth 6 and Cham 6) and one promising mutant line (L92-6) were used in this study. Six treatments were evaluated: untreated (without K application), 3 and 5 g/L foliar K application, 60 kg/ha soil K application, 3 g/L foliar K + 60 kg/ha soil K application and 5 g/L foliar K + 60 kg/ha soil K application. Plants were sprayed with 2 L/m(2)K(2)SO(4) solution three times at 5-day intervals starting at growth stage (GS) 32, and thereafter inoculated with a mixture of 15 virulent isolates of Septoria tritici at GS 33-34. The results showed that the average response to application of potassium fertilisers was positively correlated (r = 0.94) with the susceptibility level of cultivars compared with the control. The level of infection for all potassium treatments was reduced by 48%, 28% and about 0% in 1998 and by 47%, 35% and 21% in 1999 for Bohuth 6, L92-6 and Cham 6, respectively. Mean increments for grain yield ranged from 34-120% in 1998, and 80-170% in 1999 for the 5 g/L foliar K + 60 kg/ha soil K application. This combined treatment appeared to be more effective on calcareous soils, which are typical of Mediterranean environments.