Development And Application Of New Saline-alkali Compound Amendment Based On Iron Tailings

In recent years,along with the continuous economic development,people's demand for the use of land resources is getting higher and higher,but due to the lack of land resources and the serious soil pollution,the improvement of saline land has gradually become the focus of people's attention.At present,the use of industrial and agricultural wastes to improve saline-alkali land has gradually become a research hotspot.This paper takes the saline-alkali soil of Zhenlai County,Baicheng,Jilin Province as the research object,and selects industrial and agricultural waste iron tailings as the main improved material,combined with desulfurized gypsum,straw,biochar and Organic fertilizer,using indoor potting simulation method,screened out the best improver formula through orthogonal experiments,using indoor soil column experiment to explore the influence of the improver on the salt and alkali soil water and salt transport,and field experiment was carried out based on the results of the study The main research results are as follows:1.The study area was heavily alkalized saline-alkali soil with a pH value of 10.42,a sodium alkalization degree of 37.00%,a salt content of 3.81%,a cation exchange amount of more than 15.00,a high content of HCO3-,and a low content of organic matter and alkali-hydrolyzed nitrogen.2.Different treatments have significant effects on the physical and chemical properties of soil,which can effectively increase the contents of soil organic matter,K+,Ca2+ and Mg2+,and reduce the contents of soil pH,Na+,HCO3-and sodium adsorption ratio.Of which 10 g iron tailings,desulfurization gypsum,5 g chopped straw 10 g,5 g,biochar organic fertilizer 3 g formula on the physical and chemical properties of saline soil improvement effect is best,five kinds of modified materials iron tailings and desulfurization gypsum on soil pH and sodium adsorption ratio significantly,the influence of straw,biochar and organic fertilizer has significant effects on soil organic matter and potassium content.3.Different treatments had significant effects on the growth of alfalfa.Among the five materials,iron tailings had the most significant effects on plant plant height,biomass,survival rate,chlorophyll content,MDA enzyme activity,POD enzyme activity and APX enzyme activity.Moreover,when iron tailings was added at 40g,the improvement of the indexes was the best.The effect of crushed straw on SOD activity of plants was the most significant,and the SOD activity was the lowest when the added amount was 5g.When the amount of iron tailings was 40g,the improvement effect on the selective ratio of potassium and sodium ions in plant roots and leaves was the best.4.According to the evaluation of the comprehensive effect of principal component analysis on the improvement of saline-alkali soil,40g of iron tailings,lOg of desulfurized gypsum,1g of crushed straw,3g of biochar,and 15g of organic fertilizer had the highest comprehensive scores,and the improvement effect was the best in all the experimental groups.Through the analysis of variance of the comprehensive score,the results show that the best improver combination for saline-alkali soil improvement is iron tailings 40g,desulfurized gypsum 10g,crushed straw 10g,biochar 3g,organic fertilizer 3g.5.According to the analysis of soil column experiment in the laboratory,the application of the improver can significantly increase the soil's water retention performance,soil infiltration capacity,reduce the soil salt content and improve the aggregate structure of the soil.The surface application of the improver had a significant effect on the early stage of infiltration,and the improvement effect on the 0-20cm soil layer was significant.The mixed application of the improver had a more significant effect on the later stage of improvement.Compared with the control,the salt content of the 45cm soil layer decreased by 58.01%,and the water content remained above 18.00%.6.Engineering and field test results show that the improved saline soil physical and chemical properties of the basic meet normal plant growth condition,after modifying agent to improve the pH saline-alkali reduce to 8.10 or so,electric conductivity at about 5.00 ms/m3,the soil surface of Na+ and HCO3-content is significantly lower,lower levels of more than 50.00%,and there is no obvious anti salt soil underlying cation,the planting alfalfa,tall fescue,alkaline grew well,high peak strains respectively is 44.60 cm,40.60 cm and 35.50 cm,The vegetation coverage of alfalfa and alfalfa both exceeded the 90.00%level.