The Research Of Effect On Tianjin Binhai Saline Soil Improved By Acidic Residues

Tianjin Binhai area having widespread saline soil and characterized by sparse vegetation,vulnerable ecological environment and poor soil conditions,is referred to as “Green Forbidden Zone” by specialist.Tianjin,as a powerful engine,plays a decisive role in the regional development and coordination of Bohai Rim.But bottlenecks of the environmental greening existing in Binhai area have to be dealt with urgently.Through the study of modified technique for saline soil and current treatment status concerning acidic waste residue,selects 3 kinds of acidic waste residue(vinegar residue,vinasse,furfural residue)analysis its physicochemical properties.Against the typical Binhai saline-alkali soil along the downstream of Duliujian River in Tianjin City,a single-factor oriented indoor soil column simulation experiment was carried out to explore the function process,mechanism and effect of acidic waste residue in improving saline soil.Then the batter improvement effect vinegar residue was chosen to mix with other two improved material(Desulfurization gypsum and sandy soil)for the soil column experiment to verify its improvement effect.Finally,pot experiment is carried out by planting ryegrass on the modified soil,aims to provide theoretical support and technical foundation for amelioration of Tianjin Binhai saline soil and re-utilization of acidic waste residue in resources.The main results are as follows:1.The soil of 64 km downstream of Duliujian River,which in the south of Tianjin Binhai New Area(Dagang District),is the typical coastal saline soil,soil bulk density is 1.42 g/cm3,the permeation coefficient is 2.28×10-6cm/s,Clay and powder up to 85%,the soil mechanical composition is not reasonable,causing heavy texture,soil harden compaction and poor permeability.The content of soil salt is super high,the average is 18.94 g/kg,pH value is 8.36,the content of organic matter is low,the soil is full of salt and alkaline,physical and chemical properties are not good,it is useless without improved.2.The results of experiment shows that the mixed with all three kinds of acidic waste residue can significantly improve saline soil physical structure,improve permeability,the permeation coefficient is higher than treatment which was not mixed with saline soil 1-2 orders of magnitude,at the same time of improving the efficiency of water desalination,can also significantly reduce the degree of alkaline.Among them,the ability of vinegar residue and vinasse to enhance the permeability is stronger,therefore desalting efficiency are more prominent,but furfural residue has a stronger control capability to Inhibit alkaline,the improvement degree of different acidic waste residue has a Positive correlation with the proportion of added.3.Under the condition of mixed with acid residue waste separately,mixed with 20% and 30% the results of the gap is not big,in the production practice comprehensive consideration should be based on the principles of input and output efficiency,typically 20% of the content is basic can meet the requirements of improvement.4.In the mixed blending experiment,the physical structure of the soil was improved effectively,and the effect was better than that of the single factor.The conductivity and pH value of leaching solutions were similar to those of single factor blending test,but the conductivity of mixed blending decreased more rapidly and the pH value increased slightly and the speed was slower,Which is related to the addition of sand to improve the permeability of the soil and desulphurization gypsum to reduce the degree of alkalization.5.At the same time mixed blending improving soil permeability,shortening the leaching time,increased water consumption,the amount of water consumption treatment 3 up to 1720 ml,far more than water used in the treatment 1 1250 ml.Therefore,it is necessary to consider the principle of saving water while improving the soil permeability.6.Comprehensive consideration each treatment effect of desalination process,desalination,principle of input and output efficiency and saving water.The results showed that treatment 4(desulphurization gypsum 1%,sand 30%,vinasse 10%)had the best effect on the comprehensive improvement of saline soil,and the water consumption was 1320 ml.Shorten the desalting time about 30 times,the total desalting efficiency reached 89.4%,and the salt content as low as 2.01 g / kg,pH value of 7.82,is the best combination of mixed blending test and the best ratio.7.In the pot experiment,after leaching the germination rate of ryegrass reached 95%,and the growth was good,which indicated that it was very effective to improve the saline soil by mixed blending technology.The germination rate and biomass of ryegrass were best in the group 4,which is the best treatment,and the results of mixed soil column test was be proved,after mixed leaching the saline soil could meet the normal growth needs of greening plants.