| Huanghua city is a typical area of soil salinization agglomeration, development and utilization of saline land in the region has an important effect on the local ecological and economic sustainable development, and to find out the content and variation characteristics of soil salinity, nutrients can provide theoretical support for development and utilization of saline soil in the area. This paper takes Huanghua city of Hebei Province as an example, collected 310 soil samples uniform randomly in the field, through the analysis of soil characteristics, determination of salinity and nutrient content in soil; used spatial interpolation method obtained the spatial distribution of soil salinity and nutrient, analysis of the spatial distribution characteristics of salinity and nutrient; used SPSS software to analyze correlation between soil salinity and nutrient in the area; discussed variation characteristics of soil salt and nutrient from the land use types, soil types, soil textures and soil p H four aspects, the final conclusions are as follows:(1)The content of Ca2+ was 0.07~0.29 g/kg, the content of Mg2+ was 0.05~0.88 g/kg, the content of K+ was 0.04~0.26 g/kg, the content of Na+ was 0.40~7.38 g/kg, the content of Cl- was 1.45~21.20 g/kg, the content of SO42- was 0.30~2.86 g/kg, the content of HCO3- is 0.10~0.17 g/kg in Huanghua city. The most abundant was Cl-, followed by SO42-, without CO32- or CO32- content rarely. The HCO3- content had small differences between plots, distribution was uniform, salt content showed a trend of east high west low, coastal high inland low, the salt of saline soil mainly exists in the form of Na Cl, in addition, Mg2+ and HCO3- was also the main combining way of salt. The elements of soil salinity were not subject to ordinary normal distribution, but subject to the lognormal distribution. The total salt, Na+, Mg2+ for the strong variability, the variation coefficients were 161.93%, 130.01%, 123.42%; Ca2+, K+, Cl-, SO42-, HCO3- for moderate intensity variability, the variation coefficients were 49.99%, 50.37%, 98.19%, 81.20%, 16.34%.(2)The content of alkali-hydrolyzable nitrogen was 8.4~143.4 mg/kg; the content of available phosphorus was 0.4~202.7 mg/kg; the content of available potassium was 36.7~796.0 mg/kg; organic matter content was 2.2~39.3 g/kg in Huanghua city. Alkali-hydrolyzable nitrogen and organic matter content were lack, available phosphorus and available potassium content were rich; the spatial distribution of alkali-hydrolyzable nitrogen and organic matter content were uniform, the spatial distribution of the available phosphorus and potassium content were scattered. Alkali-hydrolyzable nitrogen and organic matter content showed a trend of east low west high, coastal low inland high; available phosphorus and potassium content showed a trend of east high west low, coastal high inland low. Alkali-hydrolyzable nitrogen and organic matter were subject to normal distribution, available phosphorus and available potassium were subject to lognormal distribution. Alkali-hydrolyzable nitrogen, available phosphorus, available potassium, organic matter in moderate variability, the variation coefficients were 41.7%, 59.9%, 43.5%; available phosphorus in strong variability, the variation coefficient was 115.8%.(3) From the analysis of correlation obtained that, alkali-hydrolysable nitrogen with available phosphorus content were extremely significant positive correlation, the correlation coefficient was r=0.422**; and with the organic matter content were extremely significant positive correlation, the correlation coefficient was r=0.752**; alkali-hydrolysable nitrogen with eight ions were negative correlation, with the total salt significant were extremely significant negative correlation, the correlation coefficient was r=-0.504**; available phosphorus with organic matter content were significant positive correlation, the correlation coefficient was r=0.321*, with salt ion correlation was not obvious; available potassium and potassium ions were extremely significant positive correlation, the correlation coefficient was r=0.482**, and with the other ions content and total salt content were positively correlation; organic matter and total salt content were significant negative correlation, the correlation coefficient was r=-0.296*. The total salt and Ca2+, Mg2+, K+, Na+, Cl-, SO42- were significantly correlated, and the significant relationship with Na+, Cl- were most, with HCO3- were negative correlation; there were positive correlation between Ca2+, Mg2+, K+, Na+, Cl-, SO42- each other, but HCO3- with other ions were negative ions correlation.(4) Form the variation characteristic of saline ions and nutrient, the main soil types was salinized soil, the main soil texture was in the middle level, p H value mainly in basic level 8-8.5 in Huanghua City. Under different land use types, except HCO3- content present the cultivated land and forest land in the highest level, other agricultural land in the lowest level, other salt ion content mostly present other agricultural land > grassland > unused land > garden land > cultivated land > forest land trend; Under different soil types, salt ion content mostly present coastal tidal flat soil > coastal saline soil > salinized soil > alluvial soil > damp alluvial soil > salt marsh soil, and HCO3- just had the opposite trend; Under different soil texture, salt ion content mostly present heavy loam soil > middle loam soil > sand soil > light loam soil, HCO3- content present heavy loam soil in the lowest, light loam soil in the highest; PH with HCO3- present significant negative correlation, with K+ had no obvious correlation, with other salt index present significant positive correlation, the rise of the p H play a important role in promoting soil salt ion content.Under different land use types, alkali-hydrolysis nitrogen, available phosphorus and organic matter content was higher in the garden and grassland, the other land content was low, and available potassium content was higher in the other land, cultivated land content was low; Under different soil types, alkaline-hydrolysis nitrogen content was higher in the salt marsh soil, coastal saline soil content was low, and organic matter was on the contrary, showed coastal saline soil content was higher, the minimum content was in salt marsh soil, available phosphorus and available potassium content was higher in coastal tidal flat soil, was lower in alluvial soil, damp alluvial soil; Under different soil texture, the texture was more heavy, alkali-hydrolysis nitrogen was lower, available potassium content was higher; The nutrient indexes and p H were negative correlation relationship, namely with the increase of p H, soil nutrient content gradually reduce, high p H will have certain inhibitory effect on soil nutrient content. |
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