Home › MCQs › Agronomy › Question #2073
Back to Questions
Agronomy QUESTION #2073
Question 1
The Blaney-Criddle method of estimating crop water requirements is primarily based on:
  • Net solar radiation and wind speed data
  • Mean monthly temperature and daylight hours (sunshine percentage), making it suitable for regions where only temperature data are available but less accurate than the Penman-Monteith method✔️
  • Actual measured pan evaporation data corrected by a pan coefficient
  • Soil type and available water capacity in the root zone
Correct Answer Explanation
The Blaney-Criddle formula \(ET = p(0.46T + 8)\) uses only mean monthly temperature (T) and monthly percentage of annual daylight hours (p). It was widely used before reliable radiation and humidity data were available. While simple, it overestimates ET in humid conditions and underestimates in arid climates — less accurate than the Penman-Monteith equation.