Final answer:
The required drainage coefficient in a scenario with 0.3 inches per day peak crop ET, a leaching requirement of 0.08, and an application efficiency of 76% with zero rainfall is calculated to be approximately 0.10 inches per day.
Step-by-step explanation:
The student is asking about a drainage coefficient, which is a concept used in agricultural engineering, specifically within the field of irrigation and drainage systems design. A drainage coefficient is a measure of the capacity of a drainage system to remove excess water from the soil. The peak crop evapotranspiration (ET) rate is given as 0.3 inches per day, with a leaching requirement (LR) of 0.08 (8%). With no pre-infiltration loss and a given application efficiency (AE) of 76%, we can calculate the required drainage coefficient. Since rainfall is zero, the drainage system must handle the excess water applied beyond what the crop requires for ET, accounting for inefficiencies (LR and AE).
To find the drainage coefficient, you first calculate the amount of water that needs to be applied by dividing the ET by AE: 0.3 in/day / 0.76 = 0.395 in/day. Then, subtract the ET to find the excess water: 0.395 - 0.3 = 0.095 in/day. Finally, you adjust for LR: 0.095 / (1 - 0.08) = 0.103 in/day or approximately 0.10 in/day. Therefore, the drainage system should be designed to handle a drainage coefficient of at least 0.10 inches per day.