Coastal Soil Salinity Dynamics And Its Improvement Technology

In order to explore the effects of different modifiers on the improvement of coastal saline alkali soil, the saline soil in Binhai Districtwas studied to ascertain the dynamics of coastal soil salinity in different soil layers and the distribution of salt ions. Combining with the monitoring of soil salt content on the test area of the original in 2014,the saline soil in the test area would be improved by setting different ratio of three modifiers,which were OSA, zeolite and garden waste,through the combination of indoor simulation experiment and field experiment. After data processing and beinganalyzed by periodic sampling and determination, the conclusions were drawn as followed.(1)During the period when the original soil where there was no human impactwas monitored, the content of the original soil salinity showed seasonal changes obviously, and it appeared three peaks which were May, July and September in 2014. The changes of ions to the original soil salt were consistent with the salt content. The phenomenon that original soil salinity was banked up in the test area was serious. Soil salt content in soil layer 0-20 cm was much higher than that of the other twosoil layers.In addition, the content of soil salinity in most was high. The changes about the content of Na+,K+,Mg2+,Ca2+,SO42- and Cl- ions in 0-20 cm soil layer were with time obviously. ThepH value of original soil was mostly over 8 and soil was alkaline.(2)The average value of EC and salinization of the soil in the test area wheregreen belt on both sides of the roadwas replaced by exotic soils were high.The content of soluble salt in the surface soil of 0-20 cm was differentwith an uneven distribution, and it showed a great difference between thedistribution of soil salinity on the both sides in Xueyuan Road.(3)Laboratory soil trial showed that it had good results by adding Zeolite of which the amount was 12.5 g·L-1 with other two modifiers or by adding OSA separately.(4) By combining simulation test, three kinds of modifiersin different proportions were added in field experiment. The improved depth in Area A that was on the south side of the green belt in School Road was 0-40 cm by addding six treatments which were CK, T1, T2, T3, T4 and T5. Correspondingly, the improved depth in Area B that was on the north side of the green belt in School Road was 0-20 cm by addding other six treatments which were CK2, TR1, TR2, TR3, TR4 and TR5.In Area A,5 kinds of improved treatments which were CK, T1, T2, T3, T4 and T5could significantly decrease the total salt content of 0-20cm soil during the improved periodwhen was 4 stages which were 1 months later,5 months later,9 months later and one year later. Especially,after applying treatments one year, the effect of reducing content of Na+ and Cl- was significant. The total salt content of soil 20-40 cm was significantly decreased only after 1 months of improvement. The improvement effect of the soil layer 0-20 cm was better than that of the soil layer 20-40cm. It did better that the effect of the modified treatment on the 0-20 cm of the surface layer than that of the soil layer 20-40cm.In Area B, the other five kinds of improved treatments which were TR1,TR2,TR3,TR4 and TR5 also could significantly decrease the total salt content of 0-20 cm soil in the soil layer during the period of improvement that was 4 stages which were 1 months later,5 months later,9 months later and one year later. Especially, after setting modifiors into saline soil one month, the effect of TR2, TR3 and TR4 was significantly better than that of TR5.After applying treatments one year, the effect of TR1, TR2, TR3 and TR4 was significantly better than that of TR5. The contents of, Ca2+, Mg2+, Cl-, SO42- and K’in soil were significantly decreased in the treatments by 5 kinds of modified treatments. Addtionally, value of pH was significantly reduced only by TR5.To sum up, OSA, Zeolite and Green-Wast were effective salt-reduction materials in the coastal regions of Bilateral Friendship Farm. The results would provide a theoretical basis and valuable reference to select an effective way to ameliorate coastal saline soil.