Effects of gypsum and Zn on uptake ratios of Na, K and growth‐yield of rice grown on a coastal saline soil

摘要

AbstractSalinity reduced (reduction below control = RBC) grain yield of rice by 80 and 98 at 8 and 16 mS/cm levels of saline irrigation, respectively, below tap water (0.6 mS/cm). The adverse effect of salinity was more pronounced on grain yield (98 RBC at 16 mS/cm) than on straw yield (84 RBC). The combined application of gypsum and Zn at the rates of 160 and 5 kg/ha produced 49, 45, and 41 more grain yield above controls at 0.6, 8, and 16 mS/cm levels of salinity, respectively. The length of panicles, percentage of filled grains, and 1000‐grain weight, protein concentrations of the rice grains, sum of Ca, Mg and K concentrations were reduced due to imposition of saline irrigation, but gypsum and Zn treatments significantly improved these parameters even at the highest (16 mS/cm) salinity stress. The combined application of gypsum and Zn was found to be effective to increase the protein concentrations in rice grains by 2–4 and to increase total concentrations of Ca, Mg and K, but reduced the Na/K ratios in plant tissues by 29.13, and 12 at 0.6, 8, and 16 mS/cm salinity, respectively, suggesting that the application of gypsum and Zn in parallel with irrigation of saline soils, would be effective to reduce the adverse effects of high Na/K ratios as well as to improve growth, yield, and nutritional balance in r