WATERLOGGING

Dr. M. DhakshinamoorthyProfessor (SS&AC)

IMTI, Trichy

CAUSES FOR WATER LOGGING

Poor natural drainage

Heavy downpour coupled with poor natural

drainage

Spilling of rivers and continuous submergence

Poor irrigation management without

considering soil properties

Heavy seepages from canal, distributaries and

water sources

Development activities (road/bridges/railway line)

choking of natural drains

Poor drainage system

Poor upkeep of water sheds

Hydraulic pressure from upper irrigated areas/

Seepage in low lying areas

EFFECTS OF WATER LOGGING

Accumulation of excess soluble salts in shallow

water table

Reduction of soil strength

Oxygen diffusion is 10,000 times lesser then

running water

Redox potential is – 400mV

Accumulation of Co2 , CH4, HCo3-, Co3

2- and H2S

Change in the soil pH and stabilization

(Neutral)

Anaerobes microbes exists with low energy

level

Reduced nutrient availability

Accumulation of toxicants (H2S, CH4)

Poor crop growth/nutritional disorders and

yield reduction

ILL EFFECTS ON SOIL

Lack of aeration (Oxygen)

Reduced soil temperature

Creation of salinization

Inhibiting/Reducing microbial activity

Problems in managing the soil

Obstruction to seed germination /growth

Excess weed growth

Affecting salt and water balance

Damage to building, wells, pipelines, roads etc.

Water logging causes soil salinity

Poor drainage

Sea water intrusion

Districts Ill drained & waterlogging

Salinity/Sodicity

Soil series

Area (ha) Soil series Area (in ha)

Thanjavur

Kallivayal

482(0.14%)

Kallivayal 482 (0.14%)

Thiruvarur

Kallivayal

1535 (0.8%)

Kallivayal & Kivalur

3727 (1.9%)

Naga-pattinum

Kallivayal & Naga-pattinum

10486 (4.6%)

Kallivayal, Kivalur & Nagapattinum

36845 (16.3%)

SALINITY AND WATERLOGGING IN THE COMPOSITE THANJAVUR Dt.

•Provision of surface drainage

•Lining the canals to avoid seepage and associated Stalinization

•Harvesting of the run off water and its recycling in the post rainy season

•Increasing the carrying capacity of the drainage channels by strengthening the bunds

MANAGEMENT OF WATERLOGGED SOILS

•Conjunctive use of ground water, canal water and stored rainwater to arrest/reverse the rise of water table

•Provision of check dams to prevent the sea water intrusion

•Growing saline resistant, high yielding deep water rice varieties (ADT40, CO43, TRY 1 & 2, IR 36, IR 42, Pokkali)

MANAGEMENT OF WATERLOGGED SOILS

• Irrigation induced water logging

• Poor quality irrigation water

• Salinity due to prawn culture

• Sea water intrusion

OTHER CONSTRATINTS

Coastal Soils

Characteristics

Clay < 10 % Sand > 90 %

Very low water retention capacity

pH varies from 7.9 to 8.1

EC is generally < 0.23

CEC 3.8 to 8.4 me/100g

High CaCO3 and SOM

Management of Coastal soilsProvision of Protective Embankment

Levelling the land to provide uniform drainage of excess water

Avoid summer fallow to avoid sea water intrusion

Mulching during post harvest period to improve soil properties

Lowering water table through deep drains

Grow Rice varieties that tolerate water logging and salinity

Transplant more seedlings per hill

Apply suitable amendments as and when necessary

Management of Coastal soils

Low pH (3 – 4) and medium to high salinity

High OM decomposition in brackish water under anaerobic conditions results in Iron Pyrites

Pyrites on oxidation give H2SO4 lowering soil pH

Found in Sri Lanka, Indonesia, Thailand, Vietnam, India, Senegal,

Acid Sulphate soils

Toxic concentration of Fe and Al

Low availability of Ca and P,

Shallow water table resulting in water logging,

Low base saturation.

Acid Sulphate soils

Water logged Soils – Suitable for Rice only

Never drain these soils – Pyrites gets oxidized to sulphuric acid – pH further lowered

Apply lime to increase pH and reduce toxicity of Fe and Al

Heavy doses of lime 5 – 10 t/ha every 2 to 3 years

Acid Sulphate soils

Soil Physical Constraints

Slow permeable soils

Excessive permeable soils

Sub soil hard pan

Shallow soils

Fluffy paddy soils

Surface crusting

Slow Permeable Soil

High clay content

Low Infiltration Rate – 6 cm/day

High Surface Runoff

Impeded DrainageLow nutrient availability due to fixation in clay lattice

Slow Permeable Soil 739 sq.km in Coimbatore, 526 sq.km in Dharmapuri 1243 sq.km in Trichy and 420 sq.km in Salem district

Apply organic manures 10 to 15 t/ha to improve soil physical properties

Form Ridges and Furrows to Provide aeration to roots and provide adequate drainage

Excessive Permeable Soil

High sand > 70 %

Low water and nutrient retention capacity

Weak aggregate structure due to low OM and finer fractions

6,519 sq.km in Coimbatore, 3,774 sq.km in Dharmapuri; 2,800 sq.km in Trichi, 1,837 sq.km in Madurai, 1,845 sq.km in Salem and 524 sq.km in North Arcot Districts.

Excessive Permeable Soil

Plough the soil uniformly 24 hours after rains or irrigation

The soil should be rolled 10 times with 400 kg stone roller of 1 met long (or) an empty tar drum filled with 400 kg sand

Sub soil hard panOccur in red soils – 8 m ha in T N

illuviation of clay to the sub soil horizons coupled with cementing action of oxides of iron, Aluminium and calcium carbonate

High BD – 1.8 g/cc

low infiltration, WHC, available water and movement of air and nutrients

1,320 sq.km in Coimbatore, 2,450 sq.km in Madurai and 1,448 sq.km in North Arcot districts.

Sub soil hard panAdvantages of chisel ploughingReduces the BD by 0.2 to 0.4 mg. m-3.

The hydraulic conductivity was almost doubled in sub soil

Conserves 30-40% more soil moisture.

Roots proliferation is improved by 40-45%.

Nutrient mobility especially N & K increased by 20-30% and 30-40%

Shallow Soils:

Parent rock immediately below the soil surface at about of 15-20 cm depth.

This restricts the root elongation and spreading. 209 sq.km and 384 sq.km in Salem and North arcot districts . 

Fluffy Soils:

Continuous submergence and intense cultivation – Soil structure destroyed

Low BD, Mechanical Strength, poor anchorage to plants Situation further aggravated by stubble incorporation 

Fluffy Soils:

After the harvest of Rice, when the soil is under semi-dry condition, compact the field by passing 400 kg stone roller (or) an empty tar drum filled with 400 kg of sand 8 times. 

Surface CrustingFound in red soils of Trichy, Pudukottai, Ramnad and Tirunelveli.

Colloidal oxides of iron and aluminium in alfisols bind the soil particles under wet regimes. On drying it forms a hard mass on the surface.

It prevents germination of seeds; inhibits root growth poor infiltration, accelerates surface runoff, poor aeration, affects nodule formation in leguminous crops.

Surface Crusting

Plough the soil at optimum moisture and apply lime 2 t/ha and plough again

Apply FYM or CPC 10 t/ha to improve soil physical properties

Scraping surface soil by tooth harrow will be useful.

Sprinkling water at periodical intervals may be done wherever possible.