5. Constraints of lateritic soils
Physical constraints Chemical constraints
Soil erosion and hardening of
laterites
Low water holding capacity
Reduced soil volume due to
concretions and occurrence of
plinthite and petroplinthite
Drought stress
Low CEC
Low organic matter
High acidity
Fe and Al toxicity
High Phosphorus fixation
Poor nutrient status
7. I. Soil erosion and hardening of laterites
Views of
Gullies at the
west of
Bhatina
village,
Rampurhat
Laterites are very much erosion prone soil in India because---
I. It has high erodible kaolinitic clay (B horizon)
II. Surface crusting of iron oxides
III. Light textured
IV. Low moisture retention capacity and
V. Less vegetative growth
8. IRS 1D LISS III FCC image (2001) of the Rampurhat block of Birbhum district
in West Bengal(greenishblue patches are gully prone lateritic land).
Ghosh et al (2011)
9. II. Low water holding capacity
Soil Depth(in cm) Available water(%) Infiltration Rate
Lateritic 0-15 3.5 10.8
15-30 4.6
30-60 6.3
Black 0-15 15.3 0.60
15-30 10.2
30-60 13.4
Ushakumari (1986)
Drying out and hardening of upper horizons
Forms impenetrable crust
This reduces the ability of soils to absorb water
Irreversible hardening
10. III. Reduced soil volume due to concretions and
occurrence of plinthite and petroplinthite
Plinthite is a redoximorphic feature in highly weathered soil
Product of pedogenesis, it commonly occurs as dark
red redox concretions
Changes irreversibly to an ironstone hardpan or to irregular soil
aggregates on exposure to repeated wetting and drying
Structure change from angular blocky to massive structure
12. I. Low Cation Exchange Capacity
Due to lack of organic matter
Hydrous nature of clay
Percent base saturation ranges from 80 to 95 %
which reflects the dominance of basic cations in the
exchange complex
Exchangeable Aluminium is the predominant cation.
Low activity clay, therefore CEC is contributed by
pH-dependent charges
13. II. High Soil Acidity
Measure of soil acidity in lateritic soils-
1. Exchangeable Hydrogen ion
2. Exchangeable Aluminium ion
3. Effective Cation Exchange Capacity
High acidity attributed to acidic parent material
Three strategies to attenuate soil acidity-
1. Liming to reduce Al-saturation below toxic levels
2. Liming to promote Ca and Mg in soil
3. Use of plant species tolerant to Al, Fe, Mn toxicities
Sehgal et al (2000)
14. Kisiniyio et al (2014)
Effect of lime on exchangeable Al3+ during the cropping period
on a western Kenya acid soil
15. III. High Phosphorus Fixation
High P-fixation is attributable to
1. Hydrous oxides of iron and aluminium
2. Dominance of 1:1 type of clay
3. Increased soil weathering and decreased soluble silica
4. Acidic soils have higher P-fixing capacity
5. Fe and Al phosphates are formed and adsorption reaction occurs
16. IV. Poor nutrient status
Fe and Al ions occupy negatively charged sites useful to store
nutrients
Extremely weathered laterites are devoid of primary minerals,
bases and silica
1.) Pronounced leaching
2.) Relative accumulation of sesquioxides
Deficiency of P, K, Ca, Mg, Zn, B
Toxicity of Al and Mn
Low soil fertility status
19. Bio-reclamation –Converting degraded lateritic soils into productive
land in Niger by ICRISAT
Trees intercropped with vegetables under BDL system by ICRISAT, Nigeria
Degraded lateritic soil of Nigeria
Strategy-Bio-reclamation of Degraded Lands
(BDL) system which enhanced the conversion of
degraded crusted soils into productive lands in
Niger by ICRISAT
How it was achieved- By combining indigenous
water harvesting technologies (micro-
catchments, planting pits and trenches),
application of animal and plant residues and
plantation of high-value fruit trees and annual
indigenous vegetables that are resilient to
drought environments
Tree species- Ziziphus mauritiana (Pommedu Sahel),
sweet tamarind (Tamarindus indica), the domesticated
Sclerocaria birrea (marula) and the domesticated
Acacia senegal
Leafy vegetables-(Cassia tora, Gynandropsis
gynandra, Corchorus stridens, Cerathotheca
sesamoides, Leptadenia hastate, Hibiscus sabdariffa
and wild Amaranthus).
CASESTUDY-1
20. Advantage of vermicomposted FA over FYM in
augmenting growth and yield of the crop.
Vermicomposted FA + NPK100 (A), FYM +
NPK100 (B) and yield of potato from these
treatments (C).
Location-Birbhum, West Bengal
Chattopadhyay et al (2012)
CASESTUDY-2
21. Conclusions
Laterites are formed as a result of continuous wetting and drying for
years and includes alfisols, oxisols and ultisols which are highly
weathered soils.
Lateritic soils are highly weathered soils devoid of major nutrients like P,
Ca, Mg, K, Zn, B etc. Howevever toxicity of Fe and Al may be observed
as they are acidic soils.
Liming in tropical areas are not as effective as in temperate regions due
to low activity clays.
Formation of plinthite layer hinders the root penetration for germinating
crops. However, rice can be grown as it needs hard pan formation during
its growth period.
Vermicomposting and use of fly ash are promising practices to increase
the nutrient use and its efficiency.