• Crop Water vs. Field Irrigation Requirements:
• Statement (I): Water requirement of the crops is lesser than the field irrigation requirement. $\implies$ Correct.
• Water Requirement ($WR$) represents the total consumptive use plus leaching/nursery needs. Field Irrigation Requirement ($FIR = WR - ER - S$) accounts for field application losses (conveyance, deep percolation, runoff);
• Because of application efficiency $\eta_a \lt 100\%$, $FIR = \frac{NIR}{\eta_a}$, meaning field irrigation requirement is larger than net crop requirement.
• Statement (II): Field irrigation requirement does not include contribution from other sources except irrigation. $\implies$ Incorrect.
• Net irrigation requirement explicitly deducts contributions from effective rainfall ($P_e$) and groundwater contributions ($G_w$).
• Conclusion: Statement (I) is correct but Statement (II) is incorrect (Option 3).

• Crop Coefficient Approaches in Evapotranspiration (FAO-56):
• Statement (I): Single crop coefficient approach is used for surface irrigation methods. $\implies$ Correct.
• In surface (border, furrow, basin) irrigation where the entire soil surface is wetted periodically, crop transpiration and soil evaporation are combined into a single time-averaged crop coefficient ($K_c$), yielding $ET_c = K_c \cdot ET_0$.
• Statement (II): Dual crop coefficient approach is used for micro irrigation methods. $\implies$ Correct.
• In drip/micro irrigation where only a small fraction of the soil surface is wetted frequently, $K_c$ is partitioned into basal crop transpiration ($K_{cb}$) and soil surface evaporation ($K_e$), yielding $ET_c = (K_{cb} + K_e) ET_0$.
• Conclusion: Both Statement (I) and Statement (II) are correct (Option 1).

Correct option: (1) Both Statement (I) and Statement (I) are correct

• Blaney-Criddle Evapotranspiration Method:
• Statement (I): Blaney-Criddle method uses mean temperature and monthly percentage day time hours. $\implies$ Correct.
• The empirical Blaney-Criddle formula computes consumptive use factor as $f = P(0.46 T + 8.13)$, where $T$ is mean monthly temperature (°C) and $P$ is annual percentage of daytime hours.
• Statement (II): Blaney-Criddle method was developed for the humid condition for consumptive use computation. $\implies$ Incorrect.
• The Blaney-Criddle method was developed specifically for the arid and semi-arid Western United States; it requires significant correction factors when applied to humid regions.
• Conclusion: Statement (I) is correct but Statement (II) is incorrect (Option 3).