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Improving Pasture Fertility

Fertile pasture grows more grass, holds up better under grazing and feeds cattle more reliably. Improving it is a slow job that starts with knowing what the soil lacks, not with buying a load of fertilizer.

Start with what the soil is missing

Guessing at fertility is how money gets wasted. A soil test shows nutrient levels and soil acidity, and it tells you whether a problem is a nutrient shortage, an acidity issue or something else entirely, such as compaction, poor drainage or overgrazing. Fix the biggest limit first, because adding more of something that is not the limit does little.

Take samples the way the lab or extension office directs, and keep a map of where each sample came from.

Write down what the test says and what you did about it. Two or three years of simple notes make it far easier to judge whether a change in fertility or grazing actually paid off.

Grazing management comes first

Fertility and grazing are tied together. A pasture grazed too short, too often, grows slowly and loses the roots that mine nutrients. Better rest, fewer animals or rotation can improve production before you spend anything on inputs.

Many ranchers find that a modest change in grazing does as much as a fertilizer program, and fertilizer on an overgrazed stand is partly wasted.

• Do not graze plants too short
• Rest pastures between grazings
• Spread cattle with water and mineral placement
• Control weeds that crowd out grass

Manure and nutrient cycling

Cattle return much of what they eat to the soil, but unevenly. Nutrients pile up near water, shade, feeders and loafing areas, and the far corners go without. Rotational grazing, moving feeders and bale grazing, where cattle graze hay laid out across a field, can spread nutrients more evenly.

Keep feeding sites away from streams, wells and ponds. Runoff of manure is an environmental and often a legal concern, and NRCS can help with site design.

Watch the places where cattle gather in winter, since heavy manure and trampling there can build up nutrients and bare ground at the same time.

Legumes in the mix

Legumes such as clovers host bacteria that capture nitrogen from the air, which can reduce the need for purchased nitrogen and improve forage quality. They need adequate soil acidity and nutrient levels to do well, and they can be crowded out by heavily fertilized grass.

Some legumes can cause bloat in cattle. Ask your extension agent and veterinarian about managing the risk, and do not rely on your own treatment methods.

Fertilizer decisions

When fertilizer makes sense, the soil test, the forage species and your goals decide what to use and when. Timing matters because plants take up nutrients during active growth, and rain right after application can wash nutrients away. Follow label directions, local rules and extension guidance, and keep spreaders calibrated.

Do not apply near water, on frozen ground or before heavy rain without advice. Fertilizer and fuel storage call for safe handling, so follow manufacturer and OSHA guidance.

Spread your effort across the ranch carefully. Treat the pastures that respond best, such as well-drained fields with a good stand, before the thin, rocky or wet ground that may never pay back the cost of inputs.

Cost and payback

Fertilizer prices swing, and payback depends on what the extra grass is worth to you. Compare it with options such as lowering stocking, buying hay or improving grazing. Ask your lender or accountant how it fits your budget, and use current local figures. This is education, not financial advice.

A useful question is how many extra days of grazing or how much less hay the change will bring. If you cannot answer that even roughly, wait and gather more information from your extension agent first.

Common mistakes and what to ask

Mistakes include fertilizing without a test, ignoring soil acidity, overgrazing fertilized stands and applying before a storm. Another is expecting results the first season from a slow-changing soil.

Ask your extension agent what your test means, which problem to fix first and what program assistance may exist through NRCS or FSA. Program terms change, so ask directly.

Review the plan each year with your extension agent. Rainfall, herd size and prices change, and the right program changes with them.

• No soil test
• Ignoring acidity
• Applying right before rain
• Fertilizing weedy, overgrazed pasture

More in Nutrition, Forage & Grazing

• Soil Testing on Ranches
• Lime and Fertilizer Decisions
• Weed Control in Pastures
• Brush Management on Ranches
• Poisonous Plant Control
• Pasture Renovation Basics