Which of these is NOT a method of improving crop yield?

Analyze the question: We need the option that does NOT improve crop yield, meaning the quantity of crop produced from the farm during growing and harvesting.

Concept: Crop yield is improved by practices that happen before and during growth, such as:

• Using good (viable) seeds so more germinate
• Using pest-resistant varieties so fewer plants are lost
• Applying chemicals (pesticides, herbicides, fertilizers) to protect crops and boost growth
• Mechanized farming, which allows timely, efficient planting, weeding and harvesting over larger areas

In contrast, storage is a post-harvest activity. It prevents spoilage and losses of the crop that has already been produced, but it does not increase how much the farm produced.

Going through the options:

• A. Spraying with chemicals: controls pests and diseases, which improves yield.
• B. Mechanized farming: improves efficiency and the area cultivated, which improves yield.
• C. Pest-resistant seeds: reduces crop loss, which improves yield.
• D. Storing crops in barns or silos: post-harvest preservation, so it does not increase yield.
• E. Viable seeds: gives better germination and more plants, which improves yield.

Exam tip: Separate yield improvement (pre-harvest: seeds, fertilizer, pest control, machinery) from crop preservation (post-harvest: storage, drying, canning). When you see "NOT a method of improving yield," look for the post-harvest option.