To produce different levels of water stress corresponding to 100%, 75%, and 50% field capacity in a pot experiment, you'll need to control the amount of water you provide to the plants relative to the maximum water-holding capacity of the soil. Here's how you can achieve each level:
100% Field Capacity:Start by saturating the potting mix with water until it reaches its maximum water-holding capacity. This means watering the pots thoroughly until water begins to drain from the bottom. Allow excess water to drain away, ensuring that the soil is uniformly moist but not waterlogged. After draining, measure and record the weight of each pot to establish the baseline weight at 100% field capacity. Throughout the experiment, maintain the soil moisture level by watering the plants whenever the soil starts to dry out, ensuring it remains close to saturation.
75% Field Capacity:After saturating the soil to 100% field capacity as described above, allow the pots to drain until they reach 75% of their maximum weight. This weight corresponds to the soil moisture level at 75% field capacity. To maintain this level of water stress, only water the plants when the soil dries out to a point where it reaches around 75% of the maximum weight measured after saturation.
50% Field Capacity:Follow a similar process as above to saturate the soil initially. Allow the pots to drain until they reach 50% of their maximum weight, indicating that the soil is at 50% field capacity. Throughout the experiment, maintain the soil moisture level by watering the plants only when the soil dries out to a point where it reaches around 50% of the maximum weight measured after saturation.
It's crucial to monitor the soil moisture levels regularly using a moisture meter or by weighing the pots to ensure that the desired level of water stress is maintained consistently throughout the experiment. Adjust the watering frequency and volume as needed to achieve the targeted field capacity levels and induce the desired level of water stress in the plants.