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土壤胶体与土壤吸收性能 PowerPoint PPT Presentation


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土壤胶体与土壤吸收性能. Last Class. 1 、土壤孔性 (孔隙度、相对密度、土壤容重、孔隙类型) 2 、土壤结构性 (块状、核状、柱状、片状、团粒) 3 、土壤耕性 (粘结和粘着性、可塑性、胀缩性). 问题. 1 、结合本专业所学,谈谈您对土壤耕性的认识。 2 、计算题: (1) 某土壤测得其烘干土重为 100g ,其吸湿水含量为 20 g/kg ,求其风干土重。

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土壤胶体与土壤吸收性能

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Last Class

  • 1

  • 2

  • 3


  • 1

  • 2

    (1) 100g20 g/kg

    (2)(10000m2)20cm25cm337.5g250 g/kg



  • 1-1000



1

1-1001-1000nm


2


A

a.SiO2.H2OH2SiO3

H2SiO3==H++HSiO3-== H++ SiO32-

b.

AlOH3+H+AlOH2++H2O pH<5

+

OH-

AlOH2O-+ H2O

c.




1:1


2:1

Al3+Si4+Mg2+Al3+


21


B

C-

-COOH-OH


+ + + + + +

+ - + + - + -+ - + -

+ - - + -

- +

+

- +

+ - +


1SiO2

21

2


  • A.

  • B.


  • cm2/gcm2/cm3

    2:1,



  • pH

  • 21


:pH

(pH0):pH

1-OH

2Al2O3.3H2O)

3COOH

4


1-OH

-OHH+

-OH

-OH

-OH

-O-

-O-

-O-

+3H+

pH05

11


2

pH04.8

pHpH0:

Al2O3.3H2O 2Al(OH)2++2OH-

pHpH0:

Al2O3.3H2O 2Al(OH)2O-+2OH-


3

pH

-COOH H+ + COO-

-OH H+ + -O-

pH

-NH2 -NH3+


4

SiO2.H2OH2SiO3pH02

pH


3

  • 1

  • 2



  • Fe3+ >Al3+ >Ca2+ >Mg2+ >H+ >NH4+ >K+ >Na+


  • Na+Ca2+


4

1

2

3

4

5


  • 1


  • 2


  • 3


  • 4


  • 5


  • 1

    2:11:1

  • 2

  • 3

    (pH0)

  • 4



1


K+

+CaCl2

Ca2+ +2KCl=

K+


  • 1

  • 220Ca2+39.1K+

  • 3


  • Fe3+ >Al3+ >H+ >Ca2+ >Mg2+ >NH4+ >K+ >Na+


4Cation Exchange CapacityCEC

  • pH

    cmol/kg


  • 2111

  • pHpH


  • A.CECCECCEC


  • B.

2:1>1:1>


  • C. pHH+


  • pH


  • 10 cmol/kg10~20 cmol/kg20 cmol/kg


5

  • 1BSP

    H+Al3+

    (K+Na+Ca2+Mg2+)


  • 80%

  • 80%H+Al3+


  • pH


6

1

:


2

H+Ca+Mg2+K+H+ Ca+Mg2+K+


Na+>K+>Mg2+>Ca2+>H+Al3+


3

NH4+K+


4

1.41.331.42



1

Al(OH)3 +HCl= Al(OH)2++Cl-+H2O

Al(OH)3 +NaOH= Al(OH)2O-+Na++H2O

2NH2 H+NH3+

3-OH


  • 1H2PO4-HPO42-PO43-HSiO3-SiO32-

  • 2Cl-NO3-NO2-

  • 3SO42-CO32-HCO3-


>>>

>>


1H+HB H++B-

2


soil reactionH+OH-H+Al3+Na+


  • soil acidityH+H+Al3+

  • H+Al3+CO2


1active acidity

H+pH

5 5.0-6.5 6.6-7.5 7.6-8.5 >8.5

pH4~9

pH


2potential acidity

H+Al3+Al(OH)2+Al(OH)2+Al(OH)2.50.5+1000

xH

yAl

(x+3y)K+xH++yAl3+

+(x+3y)K+=


1(exchangeable acidity)


H

+KCl=

K+HCl

K

K

K

Al

+3KCl=

+AlCl3


2

CH3COONa

CH3COONaNaOHpH8.5Na+


CH3COONa

+H2O=

CH3COOH+NaOH

H

+Na+OH- =

+H2O

Na

Na

Na

Na

Al

+3CH3COONa+3H2O=

+Al(OH)3

+3CH3COOH


1OH-

1 Na2CO3NaHCO3CaCO3

2Na+


2

1 pH

2Na2CO3NaHCO3c mol/kg

3Na+:=/*100%

5%-20%>20%


  • pH



M

+H =

H+M+

  • 1

H+H+H+

H

+MOH =

M+H2O

MOHM+OH-M+H+H+OH-H2OpH


1

1

2


  • 2

H2CO3

+Ca(OH)2=

CaCO3+2H2O

H2CO3+2NaCl

Na2CO3

+2HCl =


  • 3

R-CH-COOH

+HCl= R-CH-COOH

NH3Cl

NH2

(

R-CH-COOH

+NaOH= R-CH-COONa+H2O

NH2

NH2

(


  • 4

2Al(H2O)63+

+2OH-1=

[Al2(OH)2(H2O)8]4++4H2O

pH<4Al3+66H+OH-OH-OH-


  • 1

    pH

  • 2

    pH


  • 1

    pHpH>9.0<2.5


2

  • 1pH ,

  • 2pH


3


pH


  • 1pH6~8pH68

  • 2pH6.5~7.5pH6.5pH7.5


  • 3pH8.5 pH6~8

  • 4pH5~7.5


  • 1

  • 2CaSO4


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