The Relationship Between Soil Physical-Chemical Characteristics And Quality Of Coastal Plain

In the new urbanization development of Binhai, soil quality problem mainly focus on soil salinization, soil alkalinization and so on. Nowadays, the management of soil salinization and the recovery of fragile ecological environment have become the key work of ecological environment protection.At this situation, it will have a great importance on improving the soil fertility and conserving soil quality to recognize the process and the varying feature of soil salinization. In this study, soil samples were collected from different land use types, including farmlands, vegetable fields, orchards, artificial plantations and wetlands in Tanggu. We analysed the water soluble salt, the content of heavy metal, soil organic matter, pH value, cation exchange capacity (CEC), total phosphorus, effective state of nitrate, phosphorous, potassium and other physical and chemical properties and space changes of nutrient character of these five land usage, including 28sampling point from the soil surface. Using single factor index and comprehensive pollution index method to evaluating the soil heavy metal content. The main research results are as follows:(1) In the different land usage, There is a big difference in the nutrient content. The range of the organic matters content is 15.43-31.04 g/kg .and show a order of orchard> vegetable land >farmland >aitificial grass land> wetland; The total nitrogen content diverse from 0.65 g/kgto 1.59 g/kg, The organic matter and the total nitrogen shows a similar diverse trend. The Total phosphorus shows a high content in the orchard and vegetable land. But in the farmland,aitificial grass land and wetland shows a low content. The range of available phosphorus content is 17.39～42.75 mg/kg. Among them the available phosphorus content shows a high content in the orchard is 42.75 mg/kg.and then is vegetable land and artificial grass land, but in farmland and wetland the available phosphorus content is not to 50% of the orchard. available phosphorus content and available potassium content has a different change, the content of available potassium reach a hige content in 802.0 mg/kg, and then is the artificial grass land,farmland,orchard vegetable field, the nitrate in the vegetable field show a high content, and then is the farmland,orchard,artificial grass land,wetland; The content of ammonium nitrate nitrogen order is vegetable field> orchard >aitificial grass land> farmland> wetland(2) In the different land usage soil samples, The Soil mechanical composition Present powder grain have a high content ,Sand and viscous has a trend of low content .In the different land use type, Powder content for the order is wetland> orchard> vegetable field >farmland .CEC in the different land usage show a high content in the vegetable land. And in different land usage the order is: vegetable field >orchard> wetland> farmland.(3) In the different land usage soil, the change feature of soil content and conductivity are similar, and these two values of wet land is higher than other land usage.(4) In different land use types, the Water soluble salt has a different distribution. The average value of Cl-/SO42- is wetland aitificial grassland farmland vegetable field. And the value of (Na+ +K+)/ (Ca2++Mg2+) shows a order of orchard> wetland> aitificial grass land >farmland>vegetable field. This result shows that increase the degree of Human utilization can intensifying the soil salinization play a positive role.(5) All the averages of full amount content of Cu, Zn, Ni, Pb, Cr, Hg and As in different landuse types of soil exceeded the background values in Tianjin soil. Except the amount of Cd are less than Tianjin.The average concentration of Cu content was 60.25mg/kg, much higher than background value (26.66 mg/kg). Cu contents in different landuse types of soil were vegetable field, 74.58 mg/kg; orchard, 71.33 mg/kg; farmland, 56.80 mg/kg; wetland, 56.72 mg/kg; artificial plantation, 45.39 mg/kg, respectively. Average concentration of Zn was 137.05 mg/kg. And Zn contents in different landuse types of soil were wetland, 168.16 mg/kg; vegetable field, 157.84 mg/kg; orchard, 132.83 mg/kg; farmland, 116.13 mg/kg; artificial plantation, 103.56 mg/kg, respectively. Average concentration of Ni was 64.81 mg/kg. And Ni contents in different landuse types of soil artificial plantation 74.93 mg/kg; vegetable field, 73.32 mg/kg; wetland 70.19 mg/kg; farmland, 58.40 mg/kg; orchard, 50.56 mg/kg, respectively. Average concentration of As was 18.43 mg/kg. And As contents in different landuse types of soil were artificial plantation, 19.85 mg/kg; wetland, 17.74 mg/kg; vegetable field, 16.16 mg/kg; orchard, 14.26 mg/kg; farmland, 14.05 mg/kg, respectively.Average concentration of Hg was 0.51 mg/kg. And Hg contents in different landuse types of soil were artificial grass land, 0.74 mg/kg; wetland, 0.71 mg/kg; vegetable field, 0.68 mg/kg; farmland, 0.34 mg/kg; orchard, 0.31 mg/kg, respectively. Average concentration of Pb was 42.40 mg/kg. And Pb contents in different landuse types of soil were vegetable field, 50.06 mg/kg; wetland, 42.70 mg/kg; artificial plantation, 38.79 mg/kg; orchard, 35.36 mg/kg; farmland, 32.20 mg/kg, respectively. Average Concentrations of Cd was 0.12 mg/kg. And Cd contents in different landuse types of soil were vegetable field 0.23 mg/kg; orchard 0.14 mg/kg; wetland 0.13 mg/kg; farmland, 0.08 mg/kg. Average concentration of Cr was 71.18 mg/kg. And Cr contents in different landuse types of soil were vegetable field, 76.73 mg/kg; farmland, 74.03 mg/kg; artificial plantation, 72.98 mg/kg; wetland, 69.91 mg/kg; orchard, 69.81 mg/kg.(6) Single factor pollution index were used to evaluate heavy metal pollution. Compared with Soil Environmental Quality Standards the result shows that Zn, Pb, Cd, As,and Cr in the research area were clean; Cu in 96% soils were clean; Ni in 71% soils were clean; Hg in 75% soils were clean; and the others showed pollution more or less. Adopting background values in Tianjin soil as evaluating standard, Cu in 57% soils showed moderate pollution and in 32% soils showed light pollution, 7% soils showed sever pollution; Zn in 39% soils wrer light pollution, 50% in soils were moderate pollution, 11% in soils were sever pollution. Ni in 57% soils were light pollution, 25% in soils were moderate pollution 18% in soils were sever pollution. Pb 32% in soils were light pollution, 43% in soils were moderate pollution,25% in soils were sever pollution. 82% in soils were clean. 14% in soils were light pollution, 4% in soils were moderate pollution. As in the reaseach area mainly light pollution, and the rate is 89%.Hg in soils are mainly sever pollution,and the rate is 86. 11% in soils were moderate pollution. Cr 54% in soils were clean, 46% in soils were light pollution.(7) Integrated pollution index were used to evaluate soil environmental quality. Taking Soil Environmental Quality Standards as evaluating standard, soils in different land use types 75% in soils were clean, 29% in soils were light pollution, 14% in soils were alert level.