Water Resources

1. Water Resources – Meaning
   Water resources refer to surface water and groundwater available for agricultural, domestic, and industrial use.
2. Importance of Water in Agriculture
   Water is essential for germination, nutrient uptake, photosynthesis, and overall crop growth.
3. Types of Water Resources
   Major water resources include rainfall, rivers, reservoirs, tanks, canals, and groundwater.
4. Surface Water
   Surface water includes rivers, lakes, tanks, and reservoirs used mainly for irrigation.
5. Groundwater
   Groundwater is water stored in aquifers and extracted through wells and tube wells.
6. Rainfall as a Water Resource
   Rainfall is the primary source of water for Indian agriculture, especially in rainfed areas.
7. Irrigation – Definition
   Irrigation is the artificial application of water to crops to supplement rainfall.
8. Objectives of Irrigation
   Irrigation ensures adequate soil moisture, increases cropping intensity, and stabilises crop yields.
9. Major Irrigation Systems
   Major systems include canal irrigation, tank irrigation, and well irrigation.
10. Canal Irrigation
    Canal irrigation supplies water from rivers and reservoirs to agricultural fields through canals.
11. Tank Irrigation
    Tank irrigation stores rainwater in small reservoirs, mainly practised in South India.
12. Well Irrigation
    Well irrigation uses groundwater and is widely adopted due to its reliability and flexibility.
13. Minor Irrigation
    Minor irrigation includes small-scale systems such as tube wells, check dams, and lift irrigation.
14. Micro-Irrigation
    Micro-irrigation includes drip and sprinkler systems that improve water-use efficiency.
15. Drip Irrigation
    Drip irrigation delivers water directly to the root zone, reducing wastage and improving yields.
16. Sprinkler Irrigation
    Sprinkler irrigation simulates rainfall and is suitable for uneven and sandy soils.
17. Water-Use Efficiency (WUE)
    WUE refers to crop yield per unit of water used and is crucial in water-scarce regions.
18. Critical Stages of Irrigation
    Water stress during the flowering and grain filling stages severely reduces crop yield.
19. Waterlogging
    Waterlogging occurs when excess water saturates the soil, reducing oxygen availability to roots.
20. Drainage in Agriculture
    Proper drainage removes excess water and prevents salinity and waterlogging.
21. Salinity and Sodicity
    Improper irrigation leads to salt accumulation, affecting soil productivity.
22. Rainwater Harvesting
    Rainwater harvesting collects and stores runoff for agricultural and domestic use.
23. Watershed Development
    Watershed development ensures efficient management of land and water resources.
24. Water Resources and Climate Change
    Climate change affects rainfall variability and groundwater recharge.
25. Water Resources and NABARD
    NABARD finances irrigation projects, watershed programs, and micro-irrigation initiatives.