Abstract: We explored the effects of organic amendments under continuous cropping of oat on alkali-saline soils and oat quality in the Haitu Saline-alkali Experimental Station of Inner Mongolia Agricultural University during 2016-2018. There were four treatments, including control (CK), biofertilizer (F), rotten straw (S), and combined bio-fertilizer and rotten straw (FS). We measured soil pH, watersoluble salt ions concentration, and oat quality. The results showed that soil pH, salt content, and the concentrations of Ca²⁺, Mg²⁺, Na⁺, HCO₃^-+CO₃^2- and SO₄^2- gradually decreased, while the K⁺ and Cl^- contents increased in the 0-40 cm for all treatments with the increasing planting years of oats. Compared to the pre-improvement in 2016, the contents of soil cations (Ca²⁺, Mg²⁺, Na⁺) were decreased by 80.22%, 82.78%, 78.24% and 80.87%, and the soil SO₄^2- contents were decreased by 63.91%, 77.87%, 56.27% and 80.88%, while the soil K⁺ contents were increased by 142.00%, 171.88%, 49.65% and 93.28% in CK, F, S, FS treatments in 2018, respectively. FS treatment significantly increased crude protein content by 4.04%, increased crude fat content by 9.09%, increased K⁺ content by 6.30%, and increased Na⁺ content by 40.00% for oat grains and significantly increased crude protein content by 21.26%, neutral detergent fiber content by 2.09%, acid detergent fiber content by 4.25%, and K⁺ content by 71.24% for oat plants. The crude fat content of oat plants was significantly decreased by 6.34% after three years of improvement. Compared to CK, the correlation between soil properties and oat quality was weakened in FS treatment during the process of improvement. Therefore, the combined application of bio-fertilizer and rotten straw could effectively relief soil salinity and improve oat grain and forage qualities on saline-alkali land.

Key words: saline-alkali land, bio-fertilizer, rotten straw, soil salinity, oat quality.