Which factor is most critical when scheduling irrigation?

Crop type and its water requirements are fundamental when scheduling irrigation because different crops have varying needs based on their growth stages, climate conditions, and soil types. Understanding the specific water requirements of a crop allows for precise irrigation scheduling that meets the plant's needs without over or under-watering. This is essential for optimizing crop yield and health.

While the size of the irrigation system is important for determining the capacity to deliver water, it does not influence how much water each specific crop needs. Similarly, the market value of the crops can impact economic decisions but is not directly related to the biological needs for irrigation. Availability of labor may affect irrigation implementation but does not change the fundamental requirements of the crops themselves. Thus, focusing on crop type and its water requirements ensures that irrigation practices are effective and sustainable.