同土壤类型交换性镁含量：棕壤>潮土，与土壤交换性钙的规律一致。棕壤各亚

The exchangeable magnesium content of the same soil type: brown soil>chaos soil, consistent with the law of soil exchangeable calcium. The exchangeable magnesium content of each subtype of brown soil is not much different. The tidal brown soil is slightly higher than the typical brown soil, with an average of 302.1mg/kg, a variation of 93.3~8.1mg/kg, and a standard deviation of 141.45mg/kg; Brown soil is the lowest, with an average of 228.7mg/kg, a variation of 132.5~536mg/kg, and a standard deviation of 145.82mg/kg. The exchangeable magnesium content of each sub-category from high to low is as follows: tidal brown soil>typical brown soil>brown loamy soil>white pulped brown soil. The content of exchangeable magnesium in subgroups of Chao soil is obviously different, the content of salinized Chao soil is significantly higher than that of Chao soil subgroup, the average content is 414.22mg/kg, 251.62mg/kg; the variation of salinized Chao soil is 199~592mg/ kg, standard deviation 146.13mg/kg; fluctuating soil amplitude is 63~699mg/kg, standard deviation 140.38mg/kg. The content of exchangeable magnesium in each sub-category salinized Chao soil> Chao soil. <br>(2) Exchangeable magnesium content in different land types. The exchangeable magnesium content of different land types varies greatly. The orchards and vegetable fields are significantly higher than the grain fields. The vegetable fields are the highest, with an average content of 373.44mg/kg, a variation of 115.6~699mg/kg, a standard deviation of 142.21mg/kg, and a coefficient of variation. 38.08%; the orchard is slightly lower than the vegetable field, the average content is 365.65mg/kg, the variation range is 102~915mg/kg, the standard deviation is 139.99mg/kg

Interchangeable magnesium content with soil type: brown soil and tidal soil, consistent with the law of soil exchange calcium. The content of sub-class exchange magnesium content of brown soil is not much different, the tide brown soil is slightly higher than the typical brown soil, the average change is 302.1 mg/kg, the variation is 93.3 to 8.1mg/kg, the standard deviation is 141.45mg/kg; The content of inter-class exchange magnesium is from high to low in order: tidal brown soil, typical brown soil, brown soil, white slurp izede brown soil. The difference of the inter-class exchange magnesium content of the tide soil was obvious, the salted moisture soil content was significantly higher than that of the tide soil sub-class, the average content was 414.22 mg/kg, 251.62 mg/kg, the salted tide soil change was 199 to 592 mg/kg, the standard difference was 146.13 mg/kg; Sub-class exchange magnesium content salinized tidal soil and tide soil.<br>(2) The content of exchange magnesium of different land types. The difference between the different types of land exchange magnesium content is relatively large, orchards, vegetable land is significantly higher than grain fields, vegetable land is the highest, the average content is 373.44mg/kg, the variation is 115.6 to 699mg/kg, the standard deviation 142. 21mg/kg, variation coefficient 38.08%; Orchard slightly lower than vegetable land, average content of 365.65mg/kg, variation 102 to 915mg/kg standard deviation 139.99mg/kg

The content of exchangeable magnesium in the same soil type was brown soil > fluvo aquic soil. The content of exchangeable magnesium in brown soil was slightly higher than that in typical brown soil, with an average of 302.1 mg / kg, with a range of 93.3-8.1 mg / kg and a standard deviation of 141.45 mg / kg; the albic brown soil was the lowest, with an average of 228.7 mg / kg, with a range of 132.5-536 mg / kg and a standard deviation of 145.82 mg / kg. The order of exchangeable magnesium content of each subgroup was as follows: tidal brown soil > typical brown soil > brown soil > albic brown soil. The content of exchangeable magnesium in different types of fluvo aquic soil was significantly different, the average content of salinized soil was 414.22mg/kg, 251.62mg/kg; the range of salinized fluvo aquic soil was 199-592mg/kg, and the standard deviation was 146.13mg/kg; the variation range of fluvo aquic soil was 63-699mg/kg, and the standard deviation was 140.38mg/kg. The content of exchangeable magnesium in each subgroup was higher than that in salinized fluvo aquic soil.<br>(2) Exchangeable magnesium content of different land use types. The content of exchangeable magnesium in orchard and vegetable field was significantly higher than that in grain field, the highest in vegetable field, with an average content of 373.44mg/kg, a range of 115.6-699mg/kg, a standard deviation of 142.21mg/kg, and a coefficient of variation of 38.08%. The average content of exchangeable magnesium in orchard was 365.65mg/kg, with a range of 102-915mg/kg and a standard deviation of 139.99mg/kg<br>