Ameliorative effect of potassium sulphate on the growth and chemical composition of wheat (Triticum aestivum L.) in salt- affected soils

Potassium (K) and sodium (Na) coexist on the soil exchange complex and soil solution. Both cations may exert antagonistic or synergistic effects on mutual absorption and translocation within plants, particularly under saline and saline-sodic field conditions. This study investigated the role of K in alleviating the adverse effects of Na on wheat [Triticum aestivum (L), Iquilab-91] grown at two fields sites varying in salinity. The soils were moderately calcareous, weakly structured, mixed hyperthermic Typic Haplustepts. Site 1 was silty clay loam saline-sodic soil (ECe = 4.23-9.45 dS m-1) irrigated with groundwater with an ECiw value of 5.0 dSm -1 ; Site 2 was clay loam saline soil (ECe = 3.2-5.0 dS m-1) irrigated with groundwater with an ECiw of 2.4 dS m-1. Both sites were treated with 0, 50 and 100 kg K ha-1 applied as K2SO4 (41% K) fertilizer. Significant increases of 14 and 30% in grain yield were measured at both sites, and 35 and 54% increase in dry matter yields were observed in clay loam soil with the application of 50 and 100 kg K ha-1. Potassium application decreased leaf [Na] and significantly increased [K]; the K:Na ratio showed a positive correlation with yield. Soil analysis showed significant increases in [K], [Na] and SAR, while pH, ECe and [Ca+Mg] were not affected by the K fertilizer. The K2SO4 increased crop yield by mitigating the adverse effect of Na and would thus be an effective source of K for crop production in saline and saline-sodic soils.