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In recent years, due to climate change, as well as the impact of irrational human development and utilization, the Yellow River Delta region a series of ecological and environmental problems, such as: freshwater wetlands shrinking, the Yellow River mouth of the Yellow river courses increase in the number of vegetation degradation of ecological functions, species diversity attenuation soil salinization degree of ecological functions have been seriously damaged. Since July 2002 in the Yellow River Delta wetland restoration project since the implementation of freshwater each year in early June wetland restoration area wet period in the Yellow River to the introduction of the Yellow River water, restoration of the Yellow River Delta wetland soil nutrients and vegetation in order to clarify the sources of freshwater, this study set the four test area like places that are not carried out artificial restoration of degraded wet ground (Ⅰ), restore the three-year wet ground (Ⅱ), restore the five-year wet ground (III), restore the seven-year wet ground (Ⅳ) using a pH meter , conductivity, potassium dichromate volumetric method - eliminate cooking method, potassium dichromate - sulfuric acid digestion, 2mol/LKCl extraction - indophenol blue colorimetry, phenol disulfonic acid colorimetry, sulfuric acid - perchloric acid The consumer cooking method the, 0.05mol/LNaHCO3 Act were measured in soil pH, salinity, organic carbon, total nitrogen, ammonia nitrogen, nitrate nitrogen, total phosphorus, available phosphorus content. The results show that: (1) through freshwater recovery continued to increase the number of plant species of the Yellow River Delta wetland, in the The typical recovery recovery 7a district communities: water smartweed, cattail, and freshwater restoration contribute to the reed plant growth in the Yellow River Delta wetland plants the 7a District height to recover before the restoration of 45cm to 99.25cm; (2) With the restoration year increments soil conductivity value decreased, the difference was significant (p lt; 0.01) in the 0-20cm depth trends: 8.975 ds / m → 0.935ds / m → 0.696ds / m → 0.327ds / m, 20-40cm soil: 4.688ds / m → 1.144ds / m of → 1.027ds / m of → 0.364ds / m; kind in the recovery the ground vertical distribution also reflects the same trend ,20-40cm soil conductivity value is higher than the 0-20cm soil conductivity values, not recovery area opposite; Among the soil pH is between 8.222 to 8.477, with an average 8.353, alkaline soil, little change in amplitude, with the recovery time of the increment is not showing a clear trend; (3) surface soil organic carbon, total nitrogen content were shown with the recovery time of growth and increase trend , the difference was significant (p lt; 0.01), compared with the non-recovery area recovery 7a District, an increase of 120%; 20-40cm layer of soil organic carbon content showed a trend of decreased and then increased soil total nitrogen content of the various recovery area slightly lower than recovery zone; the different restore the life of the soil organic carbon, total nitrogen content of the spatial distribution of the characteristics consistent :0-20cm higher than 20-40cm, but did not resume on the lower total nitrogen content closer to no significant difference (p gt; 0.05); plots layers nitrate levels were lower than the content of ammonia nitrogen; (4) 0-20cm layer of soil carbon and nitrogen ratio in all sorts of places with the increase in recovery time and reduce the recovery from recovery 7.704 → 6.776 → recovery 3a 5a 6.179 → recovery 7a 5.037,20-40cm of soil carbon and nitrogen ratio showed the first decrease and then increase the trend, to recover from the recovery 6.503 → 3a, 5.869 → recovery 5a, 4.982, and after a slight rise to the recovery 7a, 6.156, less than 25; (5) recovery area total phosphorus content is slightly higher than the recovery area, all kinds of soil phosphorus content level characteristics embodied: 0 -20cm soil total phosphorus content showed a decreasing trend after the first slight increase with the growth of the recovery time, but there is no obvious trend in the 20-40cm soil; upper and lower levels in the vertical distribution of the test is still no obvious rule, and content margin; (6) Among the 0-20cm layer of soil available phosphorus content with the recovery time is showing a growing trend consistent before ,20-40cm no clear trend characteristics in the vertical direction, the non-recovery area 0-20cm layer of soil available phosphorus content is less than 20-40m depth each recovery area 0-20cm soil available phosphorus content higher than 20-40cm soil and variations from growing; (7) total nitrogen and organic carbon is closely related to the correlation reached a very significant positive relationship (r = 0.947, p lt; 0.01), the wetlands soil organic carbon, total nitrogen and pH into very significantly negatively related (r = - 0.564, -0.574; p lt; 0.01), soil NH4-N and organic carbon, total nitrogen content was significantly positively correlated (r = -0.550, -0.522; p lt; 0.05), ammonia nitrogen and nitrate was highly significant Negative relevant relationship (r = -0.226, p-lt; 0.01); wetland soil fast-acting phosphorus content and organic carbon to achieve significant positive related (r = 0.747, p-lt; 0.05), and total nitrogen reached a very significant with are related (r = 0.895, p lt; 0.01).
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