Water-salt transport characteristics during drip-evaporation in saline-alkali soil
To study the dynamics of soil moisture,salinity,and ion content during soil evaporation following a single irrigation and analyzed the patterns of surface soil salt accumulation and the functional relationship between salt content and evaporation duration,the outdoor soil column simulation experiments were carried out.Sand,clay,and loam soils were subjected to mulched and unmulched treatments to investigate the movement of water,salts,and ions in soil during evaporation after irrigation.During soil evaporation,surface soil showed an increase in total salts and Cl-,SO42-,Ca2+,Mg2+,K+,and Na+content,with the mulched treatment exhibiting a lower increase than the unmulched treatment.The increase in total salts,Na+,Cl-,and SO42-was most significant,with the highest accumulation in sandy soil and the lowest in clay soil.Throughout the evaporation process,the average daily salt concentration change rate in sandy soil was highest at 0.48 g·kg-1·d-1,while clay soil was the lowest at 0.11 g·kg-1·d-1.For ions,the daily concentration change rates of Na+and Cl-ions were the highest across different soil textures,and their upward migration patterns in mulched and unmulched treatments were similar to the general upward movement of total salts.Salt concentration in the surface soil of different soil textures was positively correlated with evaporation time.Mulching after irrigation can suppress water loss and reduce surface salt accumulation.Over time,salt ions accumulate in the soil surface with moisture evaporation,with Na+and Cl-ions accumulating most prominently in the surface layer.Na+significantly contributes to the increase in total surface soil salt content.Total salts,Na+,and Cl-accumulate the most in sandy soil and the least in clay soil.These findings provide scientific guidance for developing rational irrigation practices and secondary salinization control in saline farmlands in southern Xinjiang under the"dry sowing,wet emergence"planting technique.
saline-alkali soildry sowing wet emergenceevaporationwater and saltsionsresalt
万方数据
维普
