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Published May 16, 2011, 05:15 AM

What is the process for residue checking?

CAVALIER, N.D. — One of Tony Valvo’s complaints is that the Natural Resources Conservation Service inadequately checked crop residue for which farmers receive certain incentive payments.

By: Mikkel Pates, Agweek

CAVALIER, N.D. — One of Tony Valvo’s complaints is that the Natural Resources Conservation Service inadequately checked crop residue for which farmers receive certain incentive payments.

From June 14 to June 18, 2010, Tony Valvo says he rode with Natural Resources Conservation Service soil technician Bob Lundquist in a government pickup truck to the Walhalla, N.D. area to do “residue management checks” on land that was in various conservation tillage programs — verifying that farmers in the programs were doing the ridge tilling, no-tilling or other tillage practices they will get some payment for.

On this trip, Valvo says, all of the checks except one were done from a windshield, without stopping the vehicle.

“He’d drive along, and say, ‘That one looks like 70 percent residue out there,’” Valvo says.

Valvo describes the business of driving around as “gun-decking.” Gun-decking is a naval term that means falsifying reports. The origin likely was from midshipmen taking shortcuts when doing navigation lessons.

Valvo asked if he could check one of the fields using a “line transect method,” he says. Lundquist’s estimate was off by 10 percent, but that’s the one that was used anyway.

A “line transect” is used for making statistical estimate of crop residues — in this case a 100-foot, polyethylene yellow rope, with red tape marks at 1-foot intervals. There were two of these ropes in the office, but Valvo hadn’t seen them used. In the field, Valvo says Lindquist didn’t seem to know the process had to be done multiple times to be statistically valid, a fact that Valvo knew from his teaching days.

“One pull is not enough,” Valvo says, adding, “You don’t need to be a pointy-head with a master’s degree to go out and use a rope and repeat it five times in a field to count residue cover. You don’t need to know why. You need to know how, and you need to record the results.”

Residue by the book

The Natural Resources Conservation Service agronomy field manual, available online, specifies the use of a 50- or 100-foot measure, with graduation marks. The line is stretched at least 45 degrees off the row.

The technician should select locations in a field “randomly” and “typical.” The surveyor should look at but a “single point on each mark” on an “area about the end of a needle.” The NRCS manual tells the surveyor to “count only from one side of the line and from the same point on each mark” and “only the residue that is large enough to intercept raindrops” with a rule of thumb of about three-third-seconds of an inch in diameter.

As Tony Valvo noted, the NRCS recommends five transects per field. The manual says at five observations, the process delivers accuracy within 15 percent of the mean. It can accept three measurements to provide accuracy of 32 percent plus or minus.

If a five-measurement test shows 50 percent cover, the surveyor has a 95 percent confidence level that the true mean was between 42 percent and 57 percent cover.

Jack Russell, current acting NRCS state conservationist for North Dakota, says “normal procedure” for the transect rope is to take “two or three transects,” he says. Further, he says there are printed “guide” in the county offices for producers to “kind of tell” how much residue they have, but that “after awhile, you get proficient” at visual estimates.

“If you’re good enough, you wouldn’t have to transect every field,” he says.

Technicians take digital photographs to document their estimates in the field. He says the contracts are supposed to be checked annually at the county level and spot-checked by area or state staff.”

Paul King, NRCS state administrative officer, says residue cover is verified one of two ways: 1) visually, “by experienced employees when the determination is readily apparent” and 2) by transect, by an “inexperienced employee or if the determination is not apparent to the experienced employee.” Field verification is done before planting or after planting, but before the crop gets too high, and on all contracts.

Despite the specific instructions on transect use, and the large amounts of money involved, there is “no specified methodology” for visually assessment of residue cover, King says. Employees simply are trusted to “get the result we need with the minimum input of time.” Photographic evidence is “not required or expected,” and there is no procedure for collecting it, King says.

Statistical sampling

Valvo acknowledges it may in fact be impossible to check all of the contracts the NRCS approves.

“Nobody can check them all,” he says.

He says the answer is random sampling.

NRCS already has purchased the tools to do a valid, random sampling of fields. He says the software is built into ARCgis, which already is owned by USDA, to measure parcels of soil types in a county — often irregular shapes within fields. The same software could randomize the parcels and choose enough in each soil class, crop and soil type — to be statistically valid and officials could find those locations using GPS and do their testing.

“It is very critical that the field operatives don’t know what those numbers are going to be, because they’re going to pick winners and losers,” he says.

Valvo says the National Agricultural Statistics Service, a sister agency to the NRCS, could supply the statistical expertise to provide the random points needed for random testing, and where to test considering the limitations of personnel and equipment. Valvo would use ARC-info software to determine the “where question” for easements checking. The farmer would be required to leave some percent residue on fields for wind and soil erosion, and the NRCS is supposed to verify the land is incompliance.

Valvo says anything would beat his six-hour trip with Lundquist.

“We “just wasted gasoline,” he says. “I just asked (Bob Lundquist) why don’t you just write these people a check. He just laughed at me, with a stupid grin on his face. He thought it was funny; I didn’t think it was funny at all.”