--- title: "Food Security: What Limits Yield and What It Costs to Raise It" description: "Every way of getting more food out of the same land moves a cost somewhere else, usually onto soil, water or biodiversity. Working out which limit is actually binding on a given farm is what separates" canonical: https://lightmysky.com/learn/science/food-security-what-limits-yield-and-what-it-costs-to-raise-it-mt_SprRvGuyrK source: https://lightmysky.com/learn/science/food-security-what-limits-yield-and-what-it-costs-to-raise-it-mt_SprRvGuyrK.md retrieved: 2026-09-12 --- > **Agent view.** This is the Markdown twin of the page, for tools and assistants. > When to use this site, and the call that answers each job: https://lightmysky.com/agent-instructions.md > API description (OpenAPI 3.1): https://lightmysky.com/openapi.json · Authentication: https://lightmysky.com/auth.md > Pricing: https://lightmysky.com/pricing.md · Catalog: https://lightmysky.com/llms.txt · Full catalog: https://lightmysky.com/llms-full.txt > Every machine-readable file on this domain: https://lightmysky.com/.well-known/ai-catalog.json > Ask for Markdown with `Accept: text/markdown`, a `.md` address, or `?mode=agent`. # Food Security: What Limits Yield and What It Costs to Raise It Every way of getting more food out of the same land moves a cost somewhere else, usually onto soil, water or biodiversity. Working out which limit is actually binding on a given farm is what separates a real answer from a slogan. Subject: Science · Area: Organisms & Life Processes · Ages 15 to 16 Page: https://lightmysky.com/learn/science/food-security-what-limits-yield-and-what-it-costs-to-raise-it-mt_SprRvGuyrK ## Ready when they can - Name the main biological threats to food supply and say which are getting worse - Explain why feeding animals is an inefficient route to human food, in terms of energy transfer - Evaluate one intensive farming method by what it gains and what it costs ## Lesson: More food from the same field Food security means you and everyone around you can count on enough safe food, not just that a country grows a big harvest. Harvests are lost to pests, diseases, drought, floods and worn out soil. Climate change is spreading pests and crop diseases and shifting rain, and the poorest regions are hit hardest. Every food chain leaks energy. Plants trap only a slice of sunlight, and plant eaters turn roughly a tenth of what they eat into new body. The rest leaves as heat, movement and waste. That is why each higher level keeps only about ten percent of the level below it. **Example.** Picture a field holding 1000 units of food energy in grain. If you eat the grain, you share the full 1000 units. If cattle eat it first, about 900 units burn away keeping the animals alive, and roughly 100 units reach you as meat. Shortening the chain feeds more people from the same field. **Tip.** When you judge an intensive method, price both sides. Fertilisers boost growth but leak into rivers, pesticides kill pests but breed resistance, and irrigation drains aquifers. Name the threat, explain your method, then weigh what it gains in food against what it spends in water, pollution and wildlife. **Recap.** Less energy lost up the chain means more food on plates, and every farming method must pay its own costs. ## Practice 8 questions on this page, each with its working shown. ## Needs first - [Fertilisers, Leaching and Eutrophication](https://lightmysky.com/learn/science/fertilisers-leaching-and-eutrophication-mt_9lTF20DWOZ) - [Photosynthesis and Limiting Factors](https://lightmysky.com/learn/science/photosynthesis-and-limiting-factors-mt_PDn831oIih)