What is soil pH?

 What is soil pH?

In soil science, pH stands for "Potential of Hydrogen." It's a measure of the concentration of hydrogen ions in the soil, which determines its acidity or alkalinity.

Soil pH is one of the most important factors in crop production because it influences nutrient availability, microbial activity, and overall soil health.

Soil pH measure how acidic or alkaline the soil is, on a scale of 0 to 14.

pH < 7 → Acidic soil

pH = 7 → Neutral soil

pH > 7 → Alkaline (basic) soil

⚖️ Effects of Soil pH on Crops

1. Nutrient Availability

At very low pH (acidic soils), essential nutrients like phosphorus, calcium, and magnesium become less available.

At very high pH (alkaline soils), nutrients like iron, manganese, zinc, and phosphorus are less available.

Most nutrients are most available in the range of pH 6.0 – 7.0.

2. Toxic Elements

Acidic soils may contain toxic levels of aluminum and manganese, which damage plant roots.

Alkaline soils can cause sodium build-up, leading to poor soil structure and reduced water infiltration.

3. Soil Microorganisms

Beneficial microbes (e.g., those that decompose organic matter or fix nitrogen) thrive best in neutral to slightly acidic soils.

Extreme acidity or alkalinity reduces microbial activity, slowing nutrient cycling.

4. Crop Growth

Different crops have specific pH preferences:

Acid-loving crops: Potato, tea, sweet potato, blueberry (pH 5.0–6.0).

Neutral-loving crops: Maize, wheat, rice, soybean, vegetables (pH 6.0–7.0).

Alkaline-tolerant crops: Barley, beet, asparagus, some legumes (pH 7.0–8.0).

🛠️ Managing Soil pH

If too acidic (low pH): Apply lime (calcium carbonate) or dolomite to raise pH.

If too alkaline (high pH): Apply sulfur, gypsum, or organic matter to lower pH gradually.

Regular testing: Farmers should test soil every 2–3 years to adjust pH before planting.

Key takeaway: Soil pH determines how well crops can absorb nutrients. Maintaining the right pH for your target crops ensures healthy growth, high yields, and sustainable farming.

~ NGA AgroClimate Tech