Effects of elemental sulfur associated with gypsum on soil salinity attenuation and sweet sorghum growth under saline water irrigation

In the Brazilian semiarid region, one of the great challenges of agriculture is the adoption of cultivation strategies for saline soils utilizing saline waters.This work aims to evaluate the development of sweet sorghum and soil salinity status under increasing doses of elemental sulfur applications associated with gypsum at different irrigation levels.The work was conducted in a Cambisol, in a 4 x 5 factorial scheme, corresponding to 4 levels of elemental sulfur (0, 0.69, 1.39 and 1.99 t ha -1 ) and 5 saline irrigation levels (6, 12, 18, 24 and 30 mm), equivalent to 20, 40, 60, 80 and 100% of the soil field capacity respectively, with 4 replicates.Gypsum was applied in all treatments in a dose equivalent to 8.49 t ha -1 .The effects of these treatments were evaluated by analyzing the chemical properties of the soil and plant growth variables.Increasing elemental sulfur levels promoted reductions in soil pH and electrical conductivity of the saturation extract.Although increasing saline irrigation levels increased soil pH and decreased electrical conductivity of the saturation extract, the highest applied water levels (80 and 100% of the field capacity) negatively affected sorghum growth.Highest levels of elemental sulfur applied (1.39 and 1.99 t ha -1 ) promoted the best growth of sorghum.The study revealed that the saline irrigation level equivalent to 60% of the field capacity and the sulfur level of 1.39 t ha -1 was sufficient to reduce soil pH and salinity to a level that best promoted sorghum growth.