Roger Rohrer hasn’t committed any crimes, but he runs his farm as though he’s a man on probation. Standing outside one of his chicken houses in Pennsylvania’s Lancaster County, he points to a small fenced area down a grassy slope.

“That is a Strasburg Borough municipal well,” he said. “This whole farm drains right by that watershed.”

Several years ago, he asked his insurance company whether he could get a policy that would protect him in the event of contamination of a municipal well. The answer was no. If there was contamination, Rohrer surmised, he’d be out of business.

If Strasburg’s water supply becomes polluted and unusable, Rohrer doesn’t want anyone pointing a finger at his farm. “We believe we are farming under probation,” he said.

In the last decade and a half, “R Farm,” as it is named, has transformed from an operation where urea fertilizer was heavily applied once — two weeks before planting — into a model of nutrient management where fertilizers are carefully metered out in three smaller doses to reduce runoff and improve crop performance.

His farm — actually two farms, one of 130 acres and one of 80 acres — are

subdivided into a number of fields with different soil types. Yearly, a consultant prepares a nutrient management plan for each field. Based on soil tests, the crop being grown and other data, the plan tells Rohrer how much manure from the

1 million chickens he grows each year and how much chemical fertilizer should go on each field, and when.

He has gained a higher level of precision from several years of corn stalk nitrate tests, which provided greater insight about the amount of nitrogen the corn absorbed — and allowed fertilizer applications to be adjusted accordingly.

The plans tell him he doesn’t need as much phosphorus as is produced by his chickens. So only 200 of the 1,200 tons of chicken litter produced each year are applied to the ground. The rest is sold to a mushroom producer in Kennett Square.

After a couple crops of mushrooms have drawn down the nutrients, Rohrer brings back the poultry waste and sells it to Amish farmers who use it as mulch for their gardens. “I don’t have to apply that litter on the fields,” he said. “I currently have a place to get rid of it.”

But he’s worried that back-and-forth exchange won’t last. As Maryland implements its new phosphorus management tool, which will reduce the amount of poultry litter that can be applied to Eastern Shore farms, he is concerned the mushroom growers will be overwhelmed with poultry litter from Maryland, and not need his anymore.

“If you aren’t aware of that, and aren’t concerned about it in Lancaster County, you should be,” he said.

The first nutrient application for most of the land is poultry litter, which provides the phosphorus the crops need to start growing, along with about a third of the nitrogen and a lot of organic material that will enrich the soil.

Each spring, he watches the weather for the right temperatures and, especially, the rainfall. He wants the soil to be “receptive” to the nutrients — dry — but he also wants about half an inch of rain within a few days so the nutrients and organic materials soak into the soil, preparing it for planting.

An application of commercial nitrogen is disced a couple inches into the soil when the crop is planted, and a third “sidedress” application mixed with a stabilizer to help hold the nutrient into the soil, is dribbled between the rows when the plants are starting to grow — and will rapidly take up the nitrogen.

“It is common sense, really, but it takes more work,” Rohrer said. “It takes more equipment.”

He and his sons manage moisture as carefully as they do nutrients. The amount of residue left after harvest, and from cover crops, varies by field, with more being left on drier soils on the ridges to help them retain moisture.

“Good yields pull nutrients out of the ground. That’s why the moisture is important. If we can keep moisture in the ground and get good yields, that allows us to be profitable.”

While nutrient management is a core element, it is part of a larger conservation system employed by Rohrer on the farm.

That system includes other measures, such as planting nutrient-absorbing cover crops in the fall, using continuous no-till on his fields and planting forest buffers along his streams. Several acres of land are set aside around each chicken house to give the ground a chance to absorb the runoff from the buildings before it reaches the stream.

Not everyone is sold on his techniques. “Some of my friends think I’m nuts,” Rohrer said. But he is a fourth-generation farmer, and thinks the changes are essential if the land is to be farmed by future generations of his family.

As the public becomes further removed from farm production and has growing concerns about a clean environment, the social and political pressures — along with changing science — are going to require farmers to do a better job, he said. The wells drawing water from under his land are a constant reminder of that challenge.

“If anyone needs to be concerned about doing it by the book, or better than the book, it’s us,” he said. “But I would like to think I’d be doing it that way anyway.”

To read more about recent concerns about accounting for nutrient managment in the Bay watershed, cluck here.