Irrigation management is important for plant growth in Tamil Nadu, where the percentage of irrigated land ranges widely from 0.1% to 88% depending on the district. Irrigation is necessary due to the uncertainty of monsoon rainfall, uneven rainfall distribution, effects of different regional rainfall patterns, cultivation of high-yielding crops, and differences in soil water holding capacity. The suitability of water for irrigation depends on the amounts and types of salts present, including cations like calcium, magnesium, and sodium, and anions like chloride, sulfate, and carbonate. Water is assessed based on total salt concentration, sodium adsorption ratio, and boron content.

1. Irrigation Management
Anirudh R Bharadwaj

2. Growth of Plants
In Tamil Nadu the percentage ranges from as low of 0.1% in Nilgris to a
high of 88% in Thanjavur district. Arcot districts and Kanchipuram register 50
to 78%. Dharmapuri (19%), Salem (23%) and Dindigul (29%) are the districts
which need greater effort to increase the irrigated area.

3. Necessity of Irrigation
i) Uncertainty of monsoon rainfall
ii) Uneven distribution of rainfall
iii) Effect of winter rainfall (North India)/ Effect of SWM in South India
iv) Cultivation of high yielding crops
v) Difference in water holding capacity of the soil

4. Suitability of Water for Irrigation
• Depends on the amounts and type of salts present in water.
• Soluble constituents - Ca, Mg, Na - cations
- Cl, SO4, (CO3)2 -anions.
• Present in minute quantities are boron, selenium, molybdenum
and fluorine

5. Three parameters:
• Total salt concentration
• Sodium Adsorption ratio water
• Boron content

6. Thank You