Which of the following method is widely used in India for the computation of consumptive use?

Explanation:

• The Blaney–Criddle equation is widely used in India for estimating consumptive use (evapotranspiration) of crops due to its simplicity and reliance on readily available climate data like temperature and crop coefficients.

• Data Required: Only temperature and daylight hours, which are easily available.

• Advantages: Simple, practical, cost-effective.

• Limitations: Less accurate in extreme climates or non-standard crop conditions.

• Suitability: Preferred in Indian irrigation projects and rural planning.

Additional InformationPenman's equation

• Type: Physically based method (semi-theoretical).

• Formula Basis: Combines energy balance and aerodynamic terms.

• Parameters Used:

  • Temperature

  • Solar radiation

  • Humidity

  • Wind speed

• Advantages:

  • More accurate and scientific

  • Useful in precision agriculture or academic research

• Limitations:

  • Requires multiple climate data inputs

  • Complex calculations

• Suitability: Used in research, high-accuracy modeling, and where detailed meteorological data is available.

Tanks and Lysimeter

a) Lysimeter:

• Description: A device used to measure the actual evapotranspiration by isolating a soil volume and monitoring water inputs/outputs.

• Advantages:

  • Direct measurement

  • Highly accurate

• Limitations:

  • Expensive

  • Requires controlled setup and long-term monitoring

• Suitability: Used in research stations for calibration of empirical formulas.

b) Tanks (Class A Evaporation Pan, etc.):

• Description: Evaporation pans are used to measure evaporation losses; crop coefficient is applied to estimate consumptive use.

• Advantages:

  • Simple equipment

  • Easy to operate

• Limitations:

  • Indirect method for consumptive use

  • Influenced by pan location and wind

• Suitability: Supplementary tool for estimating evaporation, not commonly used alone for consumptive use.