Which of the following tools is commonly used for soil testing?

The commonly used tool for soil testing is indeed the soil pH meter. This instrument measures the acidity or alkalinity of the soil, which is crucial for understanding the nutrient availability for plants. Soil pH directly affects the chemical processes in the soil and influences plant growth, making it an essential factor to monitor in landscape management and gardening.

A soil pH meter provides precise readings that help landscapers and agricultural professionals make informed decisions about soil amendments and overall land management. By using this tool, one can gauge whether the soil conditions are optimal for certain plants and adjust them accordingly through the application of lime or sulfur, for instance.

While a spade, watering can, and rake are certainly useful tools for different tasks in landscaping, they do not provide the specific data required for soil testing. A spade is primarily used for digging and moving soil, a watering can is for hydration, and a rake is employed for leveling or gathering materials. None of these tools have the capability to analyze soil chemistry as effectively as a soil pH meter does.