Q&A: Everything You Need to Know About Soil pH

1: Why is soil pH important for crop growth?

Soil pH plays a critical role in crop growth because it directly impacts several key factors:

1. Nutrient Availability: The pH level affects the solubility of essential nutrients in the soil. Different nutrients are more readily available to plants at specific pH ranges. In slightly acidic to neutral soils (pH 6.0-7.0), most nutrients are accessible for plant uptake.
2. Soil Microorganism Activity: Soil pH influences the activity of beneficial soil organisms, including bacteria, fungi, and earthworms. These organisms play a crucial role in nutrient cycling and organic matter decomposition. Soil pH also affects the activity of microbes responsible for nitrogen fixation in leguminous crops.
3. Soil Structure: Proper pH balance contributes to good soil structure. Well-structured soil allows for better water infiltration, aeration, and root penetration.

2: What challenges arise in acidic soils (low pH)?

Low pH soils pose several challenges for plant growth and nutrient availability:

1. • Nutrient Imbalance: Acidic soils can reduce the availability of essential nutrients like phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg), leading to nutrient deficiencies in crops.
   • Toxic Elements: Aluminium and manganese become more soluble in acidic soils, potentially reaching toxic levels and harming plant roots.
   • Poor Microbial Activity: Soil microorganisms are less active in acidic conditions, affecting nutrient cycling and organic matter decomposition.

3: What challenges arise in alkaline soils (high pH)?

Soils with high pH levels can negatively impact plant nutrition in several ways:

• Nutrient Lockup: Alkaline soils limit the availability of iron (Fe), manganese (Mn), and zinc (Zn). These nutrients become less accessible to plants, which leads to stunted growth.
• Iron Chlorosis: High pH interferes with iron uptake, causing yellowing of leaves (iron chlorosis) in susceptible crops.

1. • Poor Nutrient Mobility: Some nutrients, like phosphorus, become less mobile in alkaline soils, leading to uneven distribution around plant roots.

4: How does extreme soil pH impact crop health and productivity?

Extreme soil pH profoundly influences crop growth:

• Root Damage: Extreme pH levels can harm root systems, affecting water and nutrient uptake.
• Reduced Crop Yield: Unfavourable pH conditions lead to stunted growth, lower yields, and poor crop quality.
• Increased Disease Susceptibility: Imbalanced pH can make plants more vulnerable to diseases and pests.

5: Can soil pH influence soil drainage?

Absolutely! Soil pH impacts drainage and water movement. Well-balanced pH levels lead to better soil structure and porosity, allowing water to infiltrate efficiently. Adequate drainage is essential for nutrient uptake and healthy root development. Additionally, proper drainage helps prevent root diseases.

6: What are the optimal pH levels for different crops?

Optimal pH varies depending on the crop. Here are some guidelines:

• Field crops (cereals): These grow well in a slightly acidic to neutral soil with a pH range of 6.0-7.0.
• Most Vegetables: Slightly acidic to neutral (pH 6.0-7.0).
• Blueberries: These acid-loving plants thrive in more acidic conditions, with a pH of 4.5-5.5.

• Tea: Tea prefers acidic soils with an optimal pH range between 4.5 and 5.5

Remember to conduct soil tests specific to your crop and adjust pH accordingly or choose crops suited to the soil pH.

7: How can farmers measure soil pH?

Farmers have a few options:

1. Periodic Soil Testing: Certified laboratories analyse soil samples, including pH measurement.
2. Field Kits: Farmers can use pH test strips for quick on-site measurements, although these are less accurate.
3. Greenhouses (Intensive Crops): Regular monitoring and automatic pH adjustments are routine in greenhouses using drip irrigation.

8: How can farmers adjust soil pH if it’s not in the ideal range?

Farmers can modify soil pH using the following methods:

• Raising pH (less acidic): Adding lime (calcium carbonate) increases soil pH. The lime reacts with soil acidity, neutralising it and making the soil less acidic. For soils low in magnesium, dolomitic lime (which contains both calcium and magnesium) is a good choice.
• Lowering pH (more acidic): Elemental sulphur can lower soil pH. It oxidises to form sulphuric acid, which increases soil acidity. Incorporating organic materials like compost or manure can gradually reduce the pH due to the release of organic acids.

Remember to consistently monitor pH levels and make necessary amendments to maintain optimal crop conditions.

9: How can farmers deal with high pH in fertigation?

ICL offers a range of water-soluble fertilisers for fertigation that help address high pH challenges and enhance nutrient uptake:

• Nova PeKacid: This product is designed to lower pH in both water and soil. It improves nutrient availability and uptake.
• Agrolution pH Low: This effective solution also helps address high pH issues while optimising nutrient delivery to crops.