Soil reaction for crops: For general field crops, the target soil pH maintained by fertilization and liming practices for optimum growth is typically in which range?

Introduction / Context:
Soil pH strongly affects nutrient availability, microbial activity, and root health. Most agronomic recommendations aim for near-neutral conditions for broad-acre crops, adjusting with lime or acidifying amendments as needed. This question asks you to identify a typical target interval for general crop production, recognizing that some specialty crops have different preferences.

Given Data / Assumptions:

• General mixed farming context (cereals, legumes, oilseeds).
• Balanced fertilizer use and standard soil amendments.
• No highly specialized crops like blueberries (acid-loving) or asparagus (alkaline-tolerant) are implied.

Concept / Approach:
Availability of major nutrients (N, P, K) and many micronutrients is maximized near neutral pH. While the absolute optimum for many crops can lie between pH 6.0 and 7.5, many extension guides accept a practical operating window extending to about pH 7–8, particularly in calcareous regions where complete neutralization is impractical. Thus, among the given ranges, 7–8 best represents the typical management target opposed to clearly suboptimal extremes.

Step-by-Step Solution:

Verification / Alternative check:
Soil-testing recommendations often prescribe lime to raise pH into the 6.5–7.0+ zone; in calcareous soils, management within 7–8 is common and productive.

Why Other Options Are Wrong:

• pH 4–5: severely acidic; aluminum toxicity and P fixation limit growth.
• pH 9–10 or 12–13: highly alkaline/caustic; micronutrient deficiencies and structure issues.
• pH 2–3: extremely acidic and unsuitable for crops.

Common Pitfalls:
Assuming one universal ideal pH; crop-specific and soil-specific targets exist, but general field practice avoids strong acidity or alkalinity.

Final Answer:
pH 7–8 (near neutral to mildly alkaline).