Volatilization is the major immediate nitrogen loss when surface-applied manure

What really happens to nitrogen when manure lands on the field surface? Let me explain it in plain terms: a big chunk of that nitrogen can take a shortcut straight into the air as ammonia gas. In fact, the major immediate loss of nitrogen from surface-applied manure is volatilization.

Volatilization: the quick vanishing act of ammonia

Volatilization is the process by which ammonia (NH3) escapes from manure into the atmosphere. When manure sits on the soil surface, the ammonia it contains is exposed to air and can vaporize rapidly. This happens especially when the surface is warm, dry, and slightly alkaline, and when the manure isn’t incorporated into the soil right away. It’s not that nitrogen disappears forever—it’s just that a portion isn’t available for the crop in need of it. And that matters, because every bit of nitrogen that evaporates is money left on the table and more nitrogen that your crops don’t get to use.

To keep things in perspective, volatilization sits in a different league from other nitrogen losses. Denitrification, leaching, and oxidation are real processes too, but they tend to operate on different timelines and under different soil conditions.

• Denitrification: This is a broader, slower process that happens when soils stay saturated and are low in oxygen. It converts nitrate into gases like nitrous oxide or nitrogen, which then escape to the air. It’s more about saturated, waterlogged soils than an immediate surface event.

• Leaching: This is the movement of nitrate down through the soil profile with water, eventually reaching groundwater. It’s a longer-term concern, especially in sandy soils or after heavy rain.

• Oxidation: In the nitrogen world, oxidation is part of soil chemistry, but it isn’t the primary culprit for the big, immediate loss after surface application. It’s more about certain chemical reactions that happen over time.

Why surface applications are asking volatilization to happen

When you broadcast manure on a field, you’re basically laying nitrogen out in the open. If the soil surface is dry and warm, the ammonia gas can surge upward into the atmosphere within hours. If the surface is wet or slightly acidic, volatilization can be slower—but it’s still a factor to watch.

Several factors push volatilization up or down:

• Soil temperature. Warmer soils, especially in spring, encourage faster ammonia loss.

• Surface pH. Alkaline or higher pH conditions on the surface make ammonia more stable as a gas.

• Moisture level. A dry, dusty surface is a bigger volatilization risk than a moist one.

• Time to incorporation. The longer the manure sits on the surface, the more opportunity there is for ammonia to volatilize.

• Manure characteristics. Manure with a high ammonia content and certain solids levels can volatilize more quickly.

What this means for Maryland fields (the practical side)

Maryland agriculture features diverse soils—from loams to clays—and a climate that can be warm and humid. On many Maryland fields, especially those with poultry and dairy operations, a large share of the nitrogen in manure is a valuable asset when it stays in the soil. If ammonia gasses off before the crop can use it, you’ll notice a few telltale signs: slower-than-expected green-up, more reliance on external nitrogen inputs, and higher costs per bushel.

Environmentally, volatilization also matters. Ammonia that escapes into the air can contribute to air quality concerns and, in sensitive areas, may affect nearby ecosystems. For farm budgeting and for responsible stewardship, reducing those losses makes both economic and environmental sense.

Simple, practical steps to curb volatilization

The good news is there are straightforward management choices that dramatically cut the risk of immediate nitrogen loss from surface-applied manure. These aren’t about fancy gadgets; they’re about timing, technique, and a touch of planning.

• Incorporate or inject when possible. The most effective way to keep nitrogen from escaping as ammonia is to get the manure into the soil as soon as you apply it. Incorporation or shallow injection limits the manure’s exposure to air and slows volatilization dramatically.

• Time your application with weather and soil conditions. If you can, apply before a forecasted rain or when soil moisture is sufficient to accept the manure and hold it in place. Dry, windy days are a volatilization risk. If weather windows aren’t favorable, waiting can pay off.

• Use surface treatments strategically. Some producers use additives or inhibitors designed to slow volatilization, especially with urea-based fertilizers. When manure contains significant ammonia, talk with your extension agent or supplier about options that are appropriate for your situation and crop plan. Always check product labels and local guidance.

• Consider surface management after application. Gentle surface roughening or light tillage (where feasible and safe for the field) can disrupt a dry, exposed surface and help incorporate some of the nitrogen sooner.

• Leverage cover crops and timing of nitrogen availability. If you’re able to plant cover crops in a timely fashion, they can start scavenging nitrogen earlier, reducing the amount that’s vulnerable to volatilization. In spring, this can be particularly helpful as fields wake up and the crop sequence shifts.

• Align animal housing and fertilizer practices. On farms with manure-rich operations, coordinating manure handling, storage, and field application to minimize exposure time helps a lot. Shorter exposure means less opportunity for ammonia to escape.

• Keep soil pH in check where appropriate. While you can’t change soil pH overnight, knowing its role helps in planning. In some cases, lime management programs can influence surface pH over time, potentially reducing volatilization risk for future applications. It’s a longer game, but it matters.

A quick “does this apply to my field?” guide

If you’re wondering whether volatilization is the big risk on your farm, ask these questions:

• Is the field dry and warm right after application? If yes, volatilization risk is higher.

• Is the manure being applied on the surface without immediate incorporation? That’s a clear red flag for ammonia loss.

• Do you have a way to inject or incorporate within a day or two? If yes, you’re on a good track to keep nitrogen in the soil.

• Are you watching local weather and soil moisture to pick a favorable day? Planning pays off here.

The bigger picture for nutrient management

Nitrogen is a high-value, high-impact nutrient. When you lose it to volatilization, you’re not only increasing fertilizer costs but also missing a link in the nutrient cycle that feeds crop growth. The aim isn’t perfection—nobody expects everything to stay put—but it is about smarter, more precise management that respects both the field’s needs and the environment.

In Maryland, that balance often translates into a practical blend of timing, technique, and a touch of patience. It’s about recognizing when surface application works and when it doesn’t, and having a plan ready to reduce losses when conditions aren’t ideal. It also means staying curious: asking questions about soil type, climate trend, and the best equipment for your operation.

A few more thoughts to keep the conversation grounded

• Not every field behaves the same. A light, sandy soil with a hot wind will volatilize more quickly than a heavy, clay-rich ground under a gentle breeze. So, tailor your approach to what your field actually does.

• The same concept shows up with other nitrogen sources too. If you’re using solid manure in combination with liquid fertilizer, the same rules of exposure apply; partial incorporation can be a smart move to minimize losses across the board.

• Education and extension services can be a real asset. Local university extension offices and state programs often have field-specific guidance that reflects Maryland’s soils, climate, and regulatory environment. A quick chat with an advisor can save both money and headaches.

Let’s bring it home

When manure lands on the surface, volatilization is the major immediate nitrogen loss you’re likely to face. It’s efficient and fast for the ammonia to slip away as a gas, especially under warm, dry, alkaline surface conditions. The science behind it is simple enough to grasp, but the implications are meaningful: more nitrogen staying in the soil means stronger crops, better yields, and less wastage.

So next time you’re planning a field day, a fertilizer application window, or a cover crop schedule, keep volatilization in mind. It’s one of those practical concepts that pay dividends when you apply it—not just in theory, but in real-world farming where the clock is ticking and every nutrient matters.

If you want, I can tailor this to a specific Maryland county or crop type, or pull in some local extension resources that people in your area rely on. Either way, the core idea stays the same: manage surface exposure, plan with the weather, and keep nitrogen where your crops can use it. That’s how you turn a quick loss into a well-timed gain.