Question

Consider the following details of crops as given below:

$\begin{array}{cccc}\text{Month}& \text{Monthly temp.}& \text{Monthly percentage}& \text{Usefull}\\ & {\text{Avg}}^{\circ }C& \text{of day time hrs. of year}& \text{rainfall (cm)}\\ \text{November}& 19.0& 7.19& -\\ \text{December}& 16.0& 7.15& 1.2\\ \text{January}& 12.5& 7.30& 0.8\\ \text{February}& 13.0& 7.03& -\end{array}$

If the latitude of the place is ${30}^{\circ }C$, then consumptive use of crop
[Use Blaney-Criddle equation and crop factor, $k=0.75$]

• A. 42.4 cm
• B. 23.85 cm
• C. 31.8 cm
• D. 56.67 cm

Answer 1

The correct option is C 31.8 cm

Using Blaney-Criddle equation,
$C_u=k\sum F$
where,
$F=\frac{P}{40}[1.8t+32]$

$\begin{array}{cccc}\text{Month}& \text{Temperature}& \text{Percentage}& \text{F}\\ \text{November}& 19.0& 7.19& 11.9\\ \text{December}& 16.0& 7.15& 10.9\\ \text{January}& 12.5& 7.30& 9.9\\ \text{February}& 13.0& 7.03& 9.7\\ & & & \sum \text{F}=42.4\end{array}$

$C_u=k\sum F$
$=0.75\times 42.4$
$=31.8cm$