Correct Answer - Option 1 : Yield of crop to the amount of water depleted by crop in evapotranspiration
Explanation:
The various types of irrigation efficiencies are given below:
1. Water Conveyance Efficiency: It is the ratio of water delivered to field (Wf) to the water diverted from reservoir (W). Mathematically it is given as:
\({\eta _c} = \frac{{\;Water\;Delivered\;to\;field\;}}{{Water\;\;diverted\;from\;reservior}}\)
Water diverted from reservoir – Water delivered to field = seepage loss in canal + Evaporation from canal.
2. Water application Efficiency: It is the ratio of water stored in the root zone (Ws) to the water delivered to field (Wf). Mathematically it is given as:
\({\eta _a} = \frac{{\;{\rm{Water\;stored\;in\;the\;root\;zone\;}}\;}}{{\;Water\;Delivered\;to\;field\;}}\)
Water delivered to field – Water stored in the root zone = Runoff + Evaporation
3. Water Used Efficiency: It is the ratio of water used consumptively to the water delivered in the field. (or) It is the yield of the crop per unit of water lost through evapotranspiration of the crop.
\({\eta _u} = \frac{{\;{\rm{Water\;used\;consumptively\;\;}}\;}}{{\;Water\;Delivered\;to\;field\;}}\)
Water Used = Water stored (Ws) – leaching – other requirements
4. Water Storage Efficiency: It is the ratio of water actually stored in the root zone and water which is to be stored in the root zone to bring the water content to its field Capacity.
\({\eta _s} = \frac{{\;{\rm{water\;actually\;stored\;in\;the\;root\;zone\;}}\;}}{{Water\;is\;to\;be\;stored\;in\;the\;root\;zone\;to\;bring\;the\;water\;content\;to\;its\;field\;capacity\;}}\)