With dairy herds at their highest level since 1993 but replacement heifers at a near 50‑year low, producers are under pressure to maximize output – both per cow and per acre. That makes crop nutrition strategy a more essential component of the system than ever for feed growers heading into early summer, especially as forage demand outpaces available acres.
Joe Leslie, a sales account manager for AgroLiquid, works with forage growers across the Northeast and sees the same patterns limit tonnage year after year. In our conversation, he breaks down the most common nutrient mistakes that suppress yield, the high‑efficiency strategies that make economic sense when margins are tight, and the practical soil and plant nutrition adjustments that matter most for summer forage planning.
Leslie brings a combination of experience to the discussion: agronomy, dairy nutrition and a lifetime on a western Pennsylvania dairy farm. After walking thousands of forage fields, he consistently sees the same issues – especially growers falling behind on nutrient removal in high‑yielding forage systems.
“If we don’t keep up with that, we’re going to hit a wall, so to speak,” he says. “And once you hit that wall, it’s really expensive to try to get back ahead.”
Here, “that” refers to replacing the large amounts of potassium (K), phosphorus (P) and micronutrients removed with every cutting. When those nutrients aren’t replenished, yields eventually decrease.
With this foundation in mind, Leslie outlines the fertility decisions that protect yield, the silent nutrient gaps that limit tonnage and the adjustments that help growers maximize production when acres are fixed.
Biggest yield‑limiting mistake: Falling behind on nutrient removal
When Leslie evaluates forage fields, one issue shows up more than anything else: growers underestimating how many nutrients forage crops remove. Forage systems export nearly all aboveground biomass, meaning the soil bank is constantly being drawn down – often faster than growers realize.
“For grass production specifically, we throw a lot of nitrogen at grass, and we see great responses,” he says. “But we continue to pull from that bank of phosphorus and potassium and other micronutrients – if we don’t keep up, we’re going to fall behind.”
Nitrogen drives early growth, but without adequate K, P, sulfur (S) and micronutrients, its efficiency drops sharply. The crop simply can’t use the nitrogen (N) growers are paying for.
“Forage production is removal, removal, removal,” adds Leslie. “It’s not like row crop production – it’s constant removal.”
High‑yielding systems remove significant amounts of nutrients, and the higher the tonnage goal, the faster the soil bank is depleted. For operations pushing for more tons per acre, nutrient replacement is not optional – it’s the foundation of sustained yield.
Potassium: The silent yield killer
Among all nutrients, K is the one Leslie sees growers fall behind on most often – and the consequences can be severe. Potassium plays a central role in water regulation, stand persistence, winter survival and regrowth. When it’s short, yield drops long before visual symptoms appear.
He points to dairy farms in the Northeast using a corn silage/triticale rotation.
“They were relying on the bank, and then they hit a wall,” he says. “And it’s really expensive to try to get back ahead.”
Potassium deficiencies rarely show dramatic visual symptoms until yields are already compromised. By the time regrowth slows or stands thin, the damage is done – and recovery can take multiple seasons and significant investment.
“Potassium is really important,” says Leslie. “It’s one that’s easy to fall behind on if you don’t stay ahead of it.”
For growers trying to increase tons without adding acres, potassium is often the first place to look.
Soil tests: Widely used, yet misinterpreted
Leslie sees more growers doing soil tests than ever before – often pulling them up on their phones. But the challenge now is interpretation, not adoption.
“Just because you have a lot of one nutrient doesn’t mean it’s a good thing,” he says. “It’s the balance of those nutrients – understanding your base saturation percentages and the balances they need to be in is really important.”
For alfalfa, calcium (Ca) levels and the Ca‑to‑magnesium (Mg) balance are especially critical. Misreading those ratios leads to poor decisions, wasted dollars and lost yield potential.
Leslie’s advice: Work with an agronomist you trust. The soil test is only as valuable as the decisions it informs.
The most important early‑season decision happens in the fall
Leslie stresses that the foundation for first‑cut yield was laid months earlier.
“Early season for first cut actually starts with the applications we made last fall to amend the soil,” he says. “Lime sources, potassium applications and fall amendments set the stage for spring growth. If those corrections weren’t made, in-season applications can only do so much.”
Fall fertility is often overlooked in forage systems, but it’s one of the most cost‑effective ways to build soil reserves and support aggressive spring growth.
Nutrient interactions that growers underestimate
Nitrogen gets the attention, but S is the nutrient Leslie sees consistently underapplied in forage systems.
“Sulfur will make nitrogen more efficient,” he says. “In hay production, I consistently see sulfur left out.”
Sulfur is essential for protein formation and N metabolism. Without it, N uptake suffers, and crude protein levels decline – even when N rates are adequate.
Other interactions matter too – K with Mg, Ca with boron (B) and the overall balance of cations. But S-N efficiency is the one Leslie believes could deliver the fastest improvement for most growers.
Where to spend fertility dollars when budgets tighten
With fertilizer prices high and margins tight, Leslie encourages growers to focus on two things:
- Feeding the plant directly – especially nutrients a crop likes (e.g., K, Ca and B for alfalfa)
- Amending the soil correctly – using the right lime source, correcting base saturations and addressing long‑term imbalances.
Leslie frames the decision this way: “If I’m going to spend that dollar, is it giving the plant something that’s going to give me yield and quality, or am I amending the soil the right way?”
Cost‑effective applications: Multiple, smaller passes
When asked which nutrient applications consistently pay back, Leslie pointed to timing, not a specific product.
“The most cost-effective applications tie back to multiple applications through the season,” he says. “Spreading out your risk and being more efficient than one big bulk spread up front.”
Multiple passes improve nutrient availability, reduce tie‑up and match supply to crop demand – especially in fast‑growing forage systems.
Placement, timing and form: The efficiency trifecta
“Placement, timing and form are really everything,” Leslie says.
Key principles he emphasizes:
- Spread applications out to improve efficiency and reduce risk.
- Choose nutrient forms that resist tie‑up and move into the plant.
- Match placement to the crop’s uptake pattern.
An analysis only tells you what was applied – not what the plant actually received.
“If it doesn’t get into the plant, it’s not paying you back,” he says. “Improving nutrient protection, timing and availability often allows growers to reduce total pounds while maintaining or increasing tonnage,” he adds.
For growers who need more tons but can’t add acres
Leslie’s advice is simple: Stay ahead of nutrient removal.
“More tons is great, but that means we’ve removed more,” he says. High‑yielding systems remove enormous amounts of nutrients, and relying on the soil bank only works for a short time.
“You may get away with it for a year,” he cautions, “but it could cost you way more down the road.”
For operations that can’t expand acreage, a full‑season, multisource fertility program – manure, dry and liquid – is often the most reliable path to higher tonnage.
