增氧灌溉与生物炭配施对盐渍土盐氮含量的影响研究OA

Coastal saline soils are known for their accumulation of surface salts,poor aeration,and low oxygen content in irrigation water.These conditions cause significant salt stress on crops and reduce soil nutrient-use efficiency,severely constraining agricultural production in coastal areas.This experiment used oxygenated irrigation technology and biochar application,with winter wheat as the test crop,to analyze changes in soil nitrogen content and water-salt transport under different treatments.The aim is to provide a new approach to improving the cultivation environment in saline soil.An outdoor pot experiment was conducted with four treatments:oxygenated irrigation alone(FO,0 g/kg,15.5 mg/L),biochar application alone(FC,10 g/kg,8.0 mg/L),combined oxygenated irrigation and biochar application(FOC,10 g/kg,15.5 mg/L),and a blank control(CK,0 g/kg,8.0 mg/L).The study focused on analyzing the differences in soil indicators(nitrogen content,water content,salt content,etc.)throughout the entire growth period of winter wheat.At the jointing stage,in the 0～20 cm soil layer,the FOC treatment significantly increased soil nitrate-nitrogen and total nitrogen content compared with the CK and FO treatments,while the FC treatment significantly increased soil ammonium nitrogen content.At this stage,soil nitrate nitrogen,ammonium nitrogen,and total nitrogen under the FO treatment were relatively low.However,in the 20～40 cm soil layer,soil nitrate nitrogen content under the FO treatment was significantly higher than under the FOC,FC,and CK treatments.The nitrification and mineralization rates under the FO and FOC treatments were significantly higher than those under the FC and CK treatments.This indicates that while oxygenated irrigation alone promotes nitrification by aerobic microorganisms,it may also cause nitrogen leaching,lowering nitrogen content in the plow layer during key growth stages.At the seedling stage,soil desalination rates in the 0～20 cm layer for the FC and FOC treatments were 0.21 and 0.16,respectively,significantly lower than those for the CK and FO treatments(0.29 and 0.25);At the jointing stage,the soil desalination rates for the FC and FOC treatments were 0.24 and 0.26,respectively,representing increases of 28.57％and 45.83％over the CK and FO treatments.This indicates that biochar may initially increase soil salt content after application but ultimately enhances the desalination rate of the topsoil.In contrast,the soil desalination rate under oxygenated irrigation alone was lower than that in the CK treatment(P<0.05).In summary,the synergistic mechanism between oxygenated irrigation and biochar application effectively overcame the aeration issues and structural limitations of saline-alkali soils.Oxygenated irrigation directly activates aerobic nitrification process,which can reduce nitrogen loss.Biochar,on the other hand,consolidates the oxygenation effect by adsorbing and retaining moisture,improving pore structure and promoting salt leaching under dynamic hydrological conditions.The coupling effect of oxygenated irrigation combined with biochar application significantly optimized water-salt transport and nitrogen transformation processes in coastal saline soils,providing a feasible integrated technical solution for the sustainable utilization of coastal saline land.