What does pH measure in soil, and why is it relevant?

pH measures the acidity or alkalinity of soil, which is a crucial factor in determining nutrient availability for plants. The pH scale ranges from 0 to 14, with a value of 7 being neutral. Soils with a pH below 7 are considered acidic, while those above 7 are alkaline.

The relevance of pH in soil lies in its direct influence on how well plants can absorb essential nutrients. Most nutrients are optimally available to plants within a certain pH range (generally between 6 and 7.5). When the pH is too low (acidic) or too high (alkaline), certain nutrients may become locked in the soil, making them unavailable to plants. For instance, iron becomes less available in alkaline conditions, leading to deficiencies that can cause chlorosis in plants. Conversely, an overly acidic soil may lead to an abundance of nutrients like aluminum, which can be toxic to plants.

Understanding and managing soil pH is vital for successful farming practices, as it can significantly impact crop health and yield. This makes the measurement of pH relevant not only for individual growers but also for overall agricultural practices in a given region.