Final answer:
Flood irrigation is not suitable for potato production because it can cause soil waterlogging and increase the risk of potato tubers rotting, leading to a lower crop yield.
Step-by-step explanation:
The type of irrigation practice that would NOT be suitable for potato crop production is C) flood irrigation. Potatoes are tubers and have specific needs for soil conditions to produce a healthy crop. Given that potatoes require well-drained soil and are susceptible to rot from standing water, flood irrigation would not be appropriate as it saturates the field with water that can lead to waterlogging of the soil, creating conditions that are conducive to tuber rot. Instead, methods such as drip irrigation, spray irrigation, and furrow irrigation allow for more controlled watering that does not saturate the soil to the same extent, thus reducing the chances of rot and other related diseases, ensuring a healthier yield of potatoes.