FFA Floriculture Practice Test

Which of the following instruments is not used to measure greenhouse crop nutrient levels?

1. pH meter

2. Conductivity meter

3. Tensiometer

4. Colorimeter

The correct answer is: Tensiometer

The correct answer indicates that a tensiometer is not used for measuring greenhouse crop nutrient levels. A tensiometer is primarily used to measure soil moisture tension, which helps growers monitor the water availability for plants. It provides information on how much water is present in the soil and how easily the plants can access that water, but it does not provide any information about nutrient levels. In contrast, the other instruments mentioned are directly related to measuring nutrient levels. A pH meter assesses the acidity or alkalinity of the nutrient solution, which is crucial for determining nutrient availability to plants. A conductivity meter measures the electrical conductivity of the nutrient solution, which correlates with the concentration of soluble salts, thereby giving an indication of nutrient levels. A colorimeter can estimate nutrient concentrations based on the color intensity of a solution, which is useful in analyzing specific nutrients. Thus, the tensiometer’s purpose distinctly diverges from the others, affirming its role as the correct answer in the context of measuring nutrient levels in greenhouse crops.