Alkali Soils

1. Management of
Alkali Soils
Presented by:
BABANJEET
L-2021-H-85-D

4. Lack of drainage
Use of basic fertilizers
Salt blown by wind
Economic Activitries
Sources of
Soluble
salts
Rock and minerals
 Halite, Feldspar,
Calcite, Dolomite etc
Arid and semi arid climate
Ground water
Ocean water

5. Sodic Soil
• Flocculation Van der Waals Attraction
• Short range attraction
Ca2+
Ca2+
Na+
Flocculated
Small hydrated
ionic radius
Dispersed
Large hydrated
ionic radius

6. Aridisols
Argids Durids
Gypsids Orthids
Alfisols
Aqualfs Udalfs
Ustalfs Xeralfs
Mollisols
Albols Aquolls
Udoll Cryolls
Inceptisols
Aquepts Orchrepts
Vertisols
Aquerts Usterts
A
A
M
I
V
05
Taxonomic Classification of
Salt Affected Soils
04
03
02
01

7. Sodic Soil –Reduced Hydraulic Conductivity
0 10 20 30 40
ESP %
Hydraulic
Conductivity

8. Specific ion
effect:
Deficiency of
cations like
Ca++ and
Mg++
Conc. of OH-
ions:
damage at
pH 10.5 or
more
Caustic
influence:
high sodicity
due to
Na2CO3 and
NaHCO3
Alkalinity
Availability of
nutrients: High
pH decreases
availability of
Ca++, Mg++, N,
Fe, Cu, Zn etc
Dispersion of
soil colloids:
Na+ acts as a
deflocculating
agent
Problems
associated
with sodic soils

9. Important Terms
[Na+]
SAR = ─────────────
√[Ca2+ + Mg2+]/2
ESP = Proportion of the cation exchange capacity occupied by the
sodium ions and is expressed as a percentage.

10.  Mechanical methods:
 Flooding and leaching
 Scrapping of surface soils
 Under drainage
Leaching requirement:
LR (%) = Ddw/Diw X 100
Where, Ddw and Diw are the depth of drainage water and depth of irrigation water, respectively.
Or
LR (%) = Eciw/Ecdw X 100
Where, ECiw and ECdw are the electrical conductivity of irrigation water and drainage water, respectively.
Amount of water required mm/season
AW = ET/1-LR
Reclamation and Management of Sodic soils

11.  Leaching and drainage
– Preconditions
• Reversible processes (Low Na+ saturation, moderate physical deterioration)
• Adequate amount of good-quality water
• Good vertical drainage of the soil profile (Light texture, good hydraulic conductivity, low alkalinity,
low ESP)
• Good horizontal drainage of the area
• Frost-free period after the vegetation season
 Prevention
• Quality control of irrigation water
• Stabilization of ground water table
– Prevention of rise
– Lowering
• Saline seep-control
Possibilities of salinity control

12.  Proper drainage
 Use of salt free irrigation water
 Planting or sowing of seeds in the furrow
 Use of acidic fertilizers
 Use of organic manures
 Ploughing and leveling of field
 Growing salt tolerant crops:
 High salt tolerant: Sugarbeet, Okra, Eggplant
 Moderately salt tolerant: Tomato, Beetroot, Peppers
 Low salt tolerant: Beans, Radish
 Sensitive crops: Lettuce, Spinach, Cabbage, Carrot.
Cultural methods

13. C
S A
S
Chemical amelioration
Soluble Sources:
Gypsum, Calcium chloride and
phospho-gypsum
Acid- formers:
Sulphur, Sulphuric
acids,
Pyrites and Lime-
sulphur
Sparingly Soluble:
Calcite and CaCo3

14. Sulphur and sulphuric acid
2 NaHCO3 + H2SO4 Na2SO4↓ + 2 CO2↑a + 2H2O
Na2CO3 + H2SO4 Na2SO4↓ + CO2↑a + H2O
Na H
Micelle + H2SO4 Micelle + Na2SO4↓
Na H
Na
Micelle + CaSO4 Micelle-Ca + Na2SO4↓
Na

15. Conversion
2NaHCO3 + CaSO4 Na2SO4 + CO2↑a + H2O + CaCO3
Leachable
Na2CO3 + CaSO4 Na2SO4 + CaCO3
Leachable
Other amendments:
FeSO4, FeS2 and lime sulphur (CaS5)
Organic amendments:
Use of organic manures and green manuring

16. Summary of Saline & Sodic soils
Summary of Saline & Sodic Soils

17. Biochar
 Three different biochars
 Maize stover biochar(MB)
 Poultry manure biochar(PB)
 Rice straw biochar(RB)
 Electricalconductivity
 EC2
 EC8 (4.6 g/L)
 EC16dS/m (9.3 g/L)

18. Net C mineralized was greater in the PB-
amended (15-23%) compared to RB (11–
19%) or MB (9–17%)
Effect on C mineralization and Soil organic
carbon content
Higher soil organic C (SOC) conc.
observed in the saline soils amended
with RB(41–67%) than PB (17–44%).

19.  RB with its greater reserve of potassium can serve as a good source of
available K in the saline soils.
 The study showed the potential of biochar derived from different
feedstocks in ameliorating saline soils.
 Greater ability of poultry manure biochar in improving resilience of
soil microbial biomass to survive under salinity was evidence of
feedstock’s type in influencing biochar behavior in stressed
environments.
Conclusion

20.  TG-B composite was prepared by using industrial by-products titanium
gypsum and biochar as raw materials and then modified by ball milling
method
 To explore the improvement effect on saline-alkali soil and plant
growth

21. Detailed process of biochar production from vegetable wastes

22. Proteobacteria,
Actinobacteria,
Gemmatimonadetes
and Bacteroidetes
A
Relative abundance
was 33.03%, 22.21%,
17.62%, and 8.88%,
respectively
B
Community histogram
at Phylum level

23. An effective strategy to
improve soil
Optimum ratio of TG-B was 10:2
TG-B and biochar promoted the
germination and growth of rice
significantly through the synergistic
effects
pH, EC, SAR and soluble
Na+ decreased by 20.74%,
77.24%, 68.77% and
44.70%
CaSO4⋅2H2O particles in TG-B were
finer, dispersed evenly, and contacted
fully with soil gelatinous particles
Conclusion

24. Thank
you