Net Wrap for Cornstalk Bales: What Hay-Wrap Buyers Need to Know

By the XES Netting team — bale net-wrap manufacturer · Updated August 16, 2026 · ~31 min read

Quick answer: do not assume the roll you run on hay will run on your baler for corn residue. Fit has to be verified against your exact make, model and identification number, the current operator manual, the machine's configuration and the physical roll label — bale or chamber width alone proves nothing. Wrap count can also change with the crop: John Deere's manual for the 468, 468 Silage Special and 568 sets a minimum of 4 wraps for corn stalks against 2 for hay, and other machines need their own manuals. But the binding is still the least consequential decision here. What actually determines whether baling cornstalks works out is how much residue you can remove without damaging the soil, whether the residue is dry enough to store, whether the crop's pesticide label allows the residue to be used the way you intend, whether it has been tested for nitrate before it reaches cattle, and whether every piece of wrap comes off before feeding.

Scope of this page. This covers dry corn stover baled after grain harvest. It does not cover whole-plant corn silage, whole-plant corn baleage, or film-wrapped high-moisture packages, which are different products with different fermentation, safety and equipment considerations. Everything below assumes a dry bale.

What corn stover is, and how much of it you have

“Corn stalks,” “corn stover” and “corn residue” all describe the leaves, stalks, cobs and husks left after the combine takes the grain.

University of Minnesota Extension reports that corn grain and stover yields are related, “typically a 1:1 ratio,” and that in their research across several Minnesota locations stover production ranged from 3.2 to 4.0 tons per acre, averaging 3.8 tons per acre, with about 0.8 tons per acre of cobs. That Minnesota work spanned irrigated and rainfed sites at grain yields from 160 to 243 bushels per acre — use it as an order-of-magnitude guide, not as a prediction for your field.

Before the baler: how much residue can you actually remove?

This is the question the original version of this article skipped, and it is the one with the longest consequences.

Iowa State University Extension writes that “recent studies suggest that only 20 to 30 percent of the total stover production could be removed for biofuel, based on ground cover requirements to control soil erosion,” while also noting that “the methods or guidelines for residue removal from any given field is not clear or well documented.” The same ISU page reports a long-term study in which stover removal versus stover returned “had reduced the total source of carbon (SC) by 20 percent and corn derived soil organic carbon by 35 percent in a 13-year period.” That ISU encyclopedia entry dates from 2007 and is framed around biofuel harvest; the erosion and soil-carbon principle applies equally when the bales go to cattle, but treat the specific percentage as dated guidance rather than a current prescription, and ask your NRCS office or agronomist what your field's slope, tillage system and rotation will tolerate.

Baling also exports nutrients. Published removal figures vary, and you should see the spread rather than a single number:

ISU states plainly that these rates “can vary widely depending on the hybrid planted, yields obtained, how much of the stover is harvested, and rainfall patterns,” and that a forage laboratory test can establish the specific analysis for your material. Note that the two sources do not agree closely on phosphate; ISU's range is per ton of dry matter and Minnesota's is a measured mean from their own locations. Run your own analysis rather than budgeting from either figure.

ISU also notes that the nitrogen picture is less certain than phosphate and potash: “the effect of harvesting stover on nitrogen fertilizer requirements is less certain. Some research shows that removing stover can actually increase the availability of nitrogen to the succeeding crop.”

Baling moisture: drier than you might expect

NDSU Extension is direct about this in its corn residue publication: “The corn stalk also can contain significant moisture, even after the plant matures. This makes baling and storing corn stalks more problematic. In most cases, 15% or less moisture is desirable for long-term storage. At levels above 15%, the likelihood of molding and spoilage increases.”

That is a stricter target than the figure the earlier version of this page carried, and it is the number to work to for stover you intend to keep. A previous version of this article said “under 18%”; we could not find a source for that and have replaced it with NDSU's 15%.

One honest gap: we could not find an Extension publication that applies hay-fire moisture thresholds specifically to baled corn stover. NDSU's concern at moisture above 15% is stated as moulding and spoilage rather than fire. Spontaneous heating in wet hay is well documented for conventional hay, and monitoring stacks for heat is sound practice regardless, but we are not going to attach a stover-specific fire threshold to a source that does not state one.

Bale weight and density: an actual formula

Iowa State's Ag Decision Maker file A1-70 gives a usable estimate rather than a rule of thumb. It states that “large round corn stover bales typically contain about 8 to 10 pounds of dry matter per cubic foot,” and gives this estimate for a large round bale of 20% moisture stalks:

  Weight (lb) = diameter (in) x diameter (in) x width (in) x 0.005
                        [ round bales, 20% moisture ]

  Worked example, 5 ft x 6 ft bale
  ---------------------------------
  round bales are quoted WIDTH x DIAMETER,
  so a 5 x 6 bale is 5 ft wide, 6 ft diameter

  width     60 in
  diameter  72 in

  72 x 72 x 60 x 0.005  =  1,555.2 lb

Two cautions on that formula. It assumes 20% moisture, so it is an as-baled wet weight at that moisture and not a dry-matter figure. And ISU itself notes that “the weight of a bale will vary considerably depending on the type of baler used and the dryness of the stover.” If weight matters commercially, weigh a representative sample of bales.

Net wrap fit and wraps per bale: verify, do not assume

An earlier version of this page told readers that the same wrap they run on hay works on corn residue, and that chamber width alone decides wrap width. That was wrong, and we have removed it. Bale or chamber width does not establish that a particular roll will run on a particular machine.

Before ordering a roll for a specific baler, confirm against the exact manufacturer, model, full serial or product identification number, the current operator manual for that machine, its configuration, and the physical label on the roll:

• the net type the machine is approved for, and the approved wrap width
• maximum roll outside diameter and maximum roll mass the machine accepts
• core inside diameter and core length
• winding direction and leader arrangement
• required supports, spacers and hardware
• the threading path for that machine
• brake and feed-system type, and the controller mode in use

Crop can also change the required wrap count, which is a separate question from fit. The answer to “will this roll work?” is conditional on those checks, not a yes.

Wrap count: at least one manufacturer does differentiate by crop

An earlier version of this page stated that we found no operator-manual source giving wrap counts, and none differentiating residue from hay. That was incorrect. John Deere publishes the instruction openly. In the operator manual for the 468, 468 Silage Special and 568 round balers (OMFH309531), under “Setting Number of Net Wraps,” Deere states that “different crops require a different number of wraps for effective baling” and gives these minimum recommendations:

The same wording appears in the later operator manual OMFH313140, which covers the 469, 469S, 569 and 569S round balers — a different, later model line, not another revision of the 468/568 manual. Deere also notes that “bales stored with less than two wraps of net wrap may be damaged by handling or weather conditions,” and provides a chart showing that if machine speed is below rated PTO speed, a higher monitor setting is needed to achieve the desired number of wraps.

Two things follow. First, this is a model-scoped instruction for those Deere balers, not a universal rule — do not carry Deere's four wraps onto another manufacturer's machine. Every other baler requires its own current operator manual for its own model and identification number. Second, the 2.5 to 3 wraps that the previous version of this article recommended for corn stover would fall below Deere's stated minimum of four for corn stalks on those models, which is a good illustration of why an article should not invent a wrap count at all.

What Extension does say about corn residue and binding

An earlier version of this page also claimed we found no authoritative source on crop differences, and none preferring net wrap to twine for residue. Both claims were wrong, and the contradicting text was on a page this article already cited. NDSU's corn residue publication states:

• “Because corn stalks are tough and large, compared with the stems of typical grass or legume forages, successfully baling corn residue with some balers may be difficult. Some manufacturers produce specialized balers just for use in harvesting corn residue. In any case, the fibrous nature of corn stover creates more wear and tear on balers.”
• “Net-wrapped bales seem to work better than twine-tied bales due to the coarseness of the material.”
• “In most cases, you will need more net wrap or twine when baling corn stalks than for conventional forages.”

Scope that carefully. NDSU supports a qualitative distinction — corn residue is coarse and tough, it is harder on balers, net wrap tends to suit it better than twine, and it generally consumes more binding than conventional forages. It does not endorse any particular product or SKU, does not establish that a given roll fits a given machine, does not describe an abrasion mechanism acting on the netting itself, does not give an exact wrap count, does not quantify cost, and does not promise a particular outcome on your machine. For the number of wraps, go back to the current manual for your exact baler.

A correction on lignin

An earlier version of this article claimed corn stover is about 18% lignin by dry weight against roughly 7–10% for mature alfalfa, and used that gap to argue stover abrades net wrap. Both halves of that were unsound.

The NREL inter-laboratory study by Templeton and colleagues, published in the Journal of Agricultural and Food Chemistry in 2010, homogenised a single corn stover sample and had seven analysts run 154 replicate analyses. Their reported lignin figure was 12.3% of dry weight, not 18%. More importantly, that value is Klason (acid-insoluble) lignin, the method used in biomass work, whereas forage laboratories report acid detergent lignin (ADL) for alfalfa. The two methods do not produce comparable numbers on the same material, so setting a biomass Klason figure beside a forage ADL figure is not a valid comparison. We have removed the claim rather than repair it. Note that this is a narrower point than it may look: NDSU does report that “the fibrous nature of corn stover creates more wear and tear on balers,” which is about the machine, and that residue generally consumes more binding than conventional forages. What was never supported is the specific claim that stover abrades the netting because of a lignin difference.

Storing stover bales outside

Ohio State University Extension's factsheet on storing corn stover describes uncovered outdoor storage this way: “The top layer of bales is exposed to sun and rain, thus reducing the quality... For the typical six bale-high storage stack, this unusable top layer results in a loss of about one-sixteenth of the dry matter. Biological activity in the other bales results in additional dry matter loss... These losses are equivalent to reducing the value of the feedstock by more than 17 percent.”

Scope that carefully before applying it. The OSU factsheet is written for biobased industry feedstock, describes large rectangular bales stacked six high, and draws its loss figure from Darr and Shah (2012). It is not a measurement of a row of round bales on the ground on your place. OSU does report that tarping “helps protect feedstock quality by preventing water from dew, rain or snow from entering the stacked bales” and that indoor storage maintains quality by reducing water entry.

We could not find a land-grant Extension publication giving measured dry-matter-loss numbers for round stover bales stored on bare ground versus an elevated, well-drained pad. Keeping bales off wet ground and away from standing water is sound practice and consistent with what OSU says about water entry, but we are not going to invent a number of weeks or a loss percentage for it, and the storage tiers this article previously carried — 0 to 60 days, 60 to 180 days, over 180 days, and a claim that bedding bales keep 9 to 12 months — had no source and have been removed.

On UV life: our own wrap, like others, is tested under DIN EN ISO 4892-2, which is a laboratory xenon-arc exposure method for plastics. That standard defines how an exposure test is run — lamp, filters, irradiance, wet and dry cycles — and does not itself establish a field service life in months. Any “12-month UV life” figure, ours included, is a manufacturer's extrapolation from laboratory hours to field time, and depends on the acceleration factor and failure criterion chosen. We have removed that claim from this page because the standard does not support it on its own.

Feeding: test for nitrate first

This is the section the earlier version of this article omitted entirely while recommending stover for a winter beef cow ration. Corn is a nitrate accumulator and baling captures the worst part of the plant.

NDSU Extension states: “The lower parts of the corn stalk will have the highest concentration of nitrates. Plant parts closest to the ground contain the highest concentrations of nitrates.” It adds that “leaves contain less nitrate than stalks or stems, while the seed and flower usually contain little or no nitrate.”

That distribution matters for baling specifically. A grazing cow takes leaf first — NDSU notes that “cattle will graze the leaves before grazing the stalk” — while a baler collects the whole plant, lower stalk included. NDSU's mitigation is height-based: “the risk of poisoning can be reduced when haying by raising the cutter bar above 6 inches or by monitoring grazing livestock and removing them when the stubble height of the plants is at 6 inches.”

NDSU also reports that “feeding drought-stressed forages from oats, barley and corn causes the majority of nitrate poisoning cases in North Dakota.” That is a state-specific observation rather than a national statistic, but it points clearly at which crops and conditions drive the problem.

Drought is not the only trigger. NDSU notes that “prolonged cool temperatures and cloudy conditions also can disrupt the conversion process,” along with “frost, hail or disease,” and that nitrogen-fertilised plants typically carry higher nitrate than unfertilised ones. SDSU Extension adds that fields receiving significant nitrogen or manure before drought are at greatest risk, and warns that “rainfall following drought conditions does not immediately eliminate nitrate concerns. In fact, nitrate levels may significantly increase for several days after a rain event.”

Drying does not fix it

This is the point most likely to catch someone out. University of Nebraska–Lincoln states: “The drying process does not decrease nitrates, so this hay may need to be diluted in the diet with other forages low in nitrates.” NDSU puts it in storage terms: “Nitrate concentrations do not decrease through time in stored forages because photosynthesis is required for conversion of nitrates in the plant. Ensiling can decrease nitrate content through fermentation, but samples still should be submitted for analysis to determine accurate levels.”

UNL quantifies the ensiling route: “If done right, ensiling can decrease nitrate content of the forage by 40 to 60%,” with proper moisture, good packing, raised chopper height, and at least 21 days of fermentation. That is a route available to chopped silage. A dry stover bale has not fermented, so it does not get that reduction.

Thresholds, and the units trap

UNL reports that “most recommendations for the level of nitrates in forages that cause issues are based on hay and it is suggested that levels above 2,100 ppm NO₃-N are toxic,” and that grazing cattle often tolerate more than cattle eating hay. UNL also cautions that “even with adaptation, feeding hay free-choice is risky when the hay has higher than 2,100 ppm NO₃-N,” because hot spots in the hay can deliver a much larger dose than the lot average suggests.

Check the units on your lab report before you compare anything to that number. Laboratories may report nitrate as nitrate-nitrogen (NO₃-N) or as the nitrate ion (NO₃), and the two differ by a factor of about 4.43. UNL's 2,100 ppm NO₃-N is roughly 9,300 ppm expressed as NO₃. Results are normally reported on a dry-matter basis. Confusing the two units is a well-known way to badly misjudge a feed, in either direction.

Sampling bales properly

NDSU is specific, and it is more work than pulling a handful from one bale: “The best testing strategy for forages that have been cut and baled is to use a bale probe to collect core samples and submit them to a laboratory for analysis. Ideally, 10% of bales or at least 20 core samples per lot of forage should be collected. A lot is defined as hay harvested within 48 hours from the same field.” NDSU also notes the Nitrate QuikTest “is not designed to evaluate nitrate content in harvested forages.”

What poisoning looks like

SDSU Extension lists “difficult and rapid breathing, mouth breathing, rapid and weak heartbeat, below normal body temperature, muscular weakness loss of muscle coordination, blue coloration of mucous membranes, marked dilation of pupils, collapse and death,” with “dark or chocolate-brown blood” as a telltale sign, and instructs producers to “pull animals from the feed source immediately and test the feed.” NDSU explains the mechanism: nitrate converts to nitrite in the rumen, and nitrite “prevents hemoglobin in red blood cells from carrying oxygen, resulting in suffocation.”

Pregnant cattle deserve particular caution. SDSU warns that “warning signs of high nitrates in the cow prior to abortions are unlikely seen, as abortions may be the first warning sign.” If you suspect nitrate poisoning, that is a call to your veterinarian, not a decision to make from a web page.

If a lot does test high

UNL describes management rather than a way to make the problem disappear: dilution with low-nitrate forage, and “grinding and blending of low and high nitrate hay is best to reduce risk.” UNL also notes that “feeding a couple pounds of corn to cattle when feeding mature high nitrate forages can lower risk. Higher dietary energy increases the rate of detoxification.” Separately, UNL advises not turning cows onto drought-stressed cornstalks hungry. And UNL warns: “Do not feed hay, straw, or fodder suspected of being high in nitrate when it is damp. Damp hay tends to be more toxic because some of the nitrate already has been converted to the more toxic nitrite before being consumed.”

Build the ration with your veterinarian or a nutritionist against your actual lab numbers and the class of cattle involved. None of the figures above are a ration.

Feeding: every piece of wrap has to come off

As a net wrap manufacturer we would rather you knew this than not.

SDSU Extension states: “Net wrap and other plastic hay binding materials are not digestible in the rumen, so a treatment for [net wraposis] is not available. The best plan is prevention.”

University of Nebraska–Lincoln's BeefWatch summarises the research: “Research by North Dakota State University (NDSU) has shown that the rumen microbes do not digest plastic net wrap or biodegradable twine. Sisal twine does get digested but at a much slower rate compared to hay.” In an NDSU study, “steers were fed net wrap in a ration until 14 days prior to harvest to determine if the material would pass through the digestive system. However, there was still a significant amount of net wrap remaining in the rumen after 14 days.”

UNL describes what accumulates: “Cows fed ground, net wrapped hay for 140 days in an SDSU study accumulated a softball-sized mass in the rumen consisting of 0.8 to 1.1 pounds of net wrap. The entangled mass of net wrap and feed measured around 3 feet in length when stretched out. Based on the amount of net wrap offered through the diet, about 53% of the net wrap was recovered through rumen evacuations.” UNL adds that Montana State University research found 47% of offered net wrap recovered from the digestive tract.

Grinding is not a solution. UNL is explicit: “While grinding net wrapped bales may reduce the particle size compared to feeding intact net wrap, health issues can still occur.” SDSU's producer survey found that when grinding bales, 11% of producers removed net wrap or twine and 18% did not. In that same survey, among respondents who had livestock mortality, 26% had a veterinarian conduct postmortem exams, and 30% of those reported recovering net wrap from inside the animal.

The practical rule is simple: remove all net wrap and twine before cattle can reach the forage, and account for the pieces. Follow the operator manual for your processor, bale bed or feeder, and keep clear of crush and roll zones when handling bales — support and stabilise a bale before cutting anything, and never cut wrap from a raised bale.

What baled stover can and cannot do in a ration

NDSU's corn residue publication gives an average composition for corn stover on a dry matter basis of 5.0% crude protein, 49.0% TDN, 42.4% ADF and 7.2% ash, describing it as “generally low in protein and digestibility, compared with grass hay, but higher in quality than most cereal straws.” University of Minnesota Extension reports comparable figures: “about 5% crude protein, 70% NDF concentration, and 50% dry matter digestibility,” adding that stover “is often used in maintenance rations of non-lactating beef cows” and that “supplementation with energy and protein are required if corn stover is the primary ingredient in rations for growing and lactating animals.”

Iowa State frames the same point economically: “when supplemented with protein, vitamins and minerals, stover can supply the nutritional needs of cows that are in moderately good body condition during fall and early winter.”

Baled stover is not the same feed as grazed stover

This distinction matters and is easy to miss. NDSU states: “While grazed corn residue can serve as the sole source of forage for beef cows, harvested or baled corn stover should not be utilized as the sole source of forage in winter feeding programs because the harvested material typically contains a greater proportion of stalk and cob, which are less nutritious than the leaf and husk.”

Minnesota describes the same mechanism from the grazing side: cattle “can be more selective and eat the higher quality leaves and grain lost in combining,” and “baled corn stover is often lower in quality than grazed stover because of field harvesting losses which include chopping, shredding, and raking.”

So a grazing figure is not transferable to a bale, and the low-quality stalk fraction that carries the most nitrate is also the fraction baling concentrates. Both of those point the same direction: test the material you actually baled.

Mould and mycotoxins

Iowa State reports that in hail-damaged corn, “ear rot severity and mycotoxin severity were significantly greater in hail damaged fields compared to fields that were not damaged by hail,” that ear rot severity predicted vomitoxin and zearalenone contamination, and that “approximately 50 percent of the grain samples from hail-damaged fields were above FDA regulation levels.” ISU adds that “while ear rots do not always result in toxin problems, they are a warning sign to suspect toxins.”

An honest limit on that: ISU's work there addresses grain and silage. We did not find an Extension publication that sets a specific threshold for baling residue out of an ear-rot-affected field. What follows reasonably is that a field with visible ear rot is a reason to test before feeding rather than a reason to assume the residue is fine, and that decisions about feeding suspect material belong with your veterinarian and a laboratory. Do not treat the absence of visible mould in a bale as evidence that it is clean.

Pesticide labels and harvest contamination

Two gates sit between a standing crop and a legal, usable bale, and neither is about the wrap.

The current physical product label controls what the residue may be used for. Before baling residue for feed or bedding, read the actual label on the containers of every product applied to that crop, for the season in question — not a remembered rate or a summary. Some labels restrict or prohibit harvesting treated crop residue for feed or bedding, and set pre-harvest and grazing intervals. Those feeding, grazing and manure restrictions travel with the lot: they follow the bales to whoever feeds them, and they can apply to manure from animals that ate the residue. If you sell the bales, the applied products, application dates and any restrictions have to be disclosed with them, because the buyer cannot read a label they have never seen.

Baled residue picks up more than plant material. Because residue is gathered off the ground, soil, stones and other foreign material can end up in the bale, and how much depends on the collection method and cutting height — shredding, raking and windrow handling all sit closer to the soil surface than a hay swath does. That matters in two ways: ingested soil and stones are a hazard to animals and to processing equipment, and soil contamination raises the ash fraction, which dilutes the feed value that a laboratory report will show. It is another reason to test the material you actually baled, run equipment according to its manual, and inspect for foreign objects before processing.

What this page cannot tell you

• Whether your residue is safe to feed. A representative sample and a selected set of analytes, read with your veterinarian or nutritionist, can support a decision — but no analysis proves a heterogeneous lot is free of every hazard. Results are bounded by how and where samples were taken, how many cores, how the lot was defined, which analytes were requested, and each method's limit of detection. Nitrate and mycotoxin contamination in particular is often clustered rather than evenly spread, so a clean result on one set of cores does not clear the whole lot.
• How much residue your fields can spare. That depends on slope, soil, tillage and rotation; ask NRCS or your agronomist.
• What your bales weigh. Estimate with the ISU formula, then weigh a representative sample — scale weight, not a formula, should control handling and sale.
• Whether a given roll of net wrap fits your baler, or how many wraps it should apply. Both come from the current operator manual for your exact machine, its identification number and configuration, checked against the physical roll label.
• Whether the residue may legally be fed or used as bedding. That comes from the current label on the products applied to that crop.
• How long your bales will hold up outside. We removed the day-count tiers this page used to carry because we could not source them.

If you are buying or selling stover bales

Whichever side you are on, put the following in writing rather than assuming it:

• Field, hybrid and harvest date, and whether the crop was drought-stressed, hailed, frosted or showed ear rot
• Every pesticide product applied to that crop, the application dates, and any harvest, feeding, grazing or manure restrictions on the current label
• Nitrogen and manure history on that field
• Collection method and cutting height, since these affect soil, stone and ash content
• Baled moisture and how it was measured, plus storage since baling — inside, tarped, or open ground
• Bale width and diameter, and a representative measured weight with the moisture basis stated
• Whether a representative cored lot analysis exists, including nitrate, with its date and the units used
• Binding type, and who is responsible for removing and disposing of it
• Price unit — per bale or per ton, and at what moisture — plus delivery and unloading terms

No seller, us included, can guarantee that a given lot is suitable for a given class of animal.

Frequently asked questions

Can I use the same net wrap for cornstalk bales as for hay?

Do not assume so. Bale or chamber width does not establish that a roll will run on a given machine. Verify against the exact manufacturer, model, full serial or product identification number, the current operator manual, the machine's configuration and the physical roll label: the approved net type and width, maximum roll outside diameter and mass, core inside diameter and length, winding direction and leader, required supports, spacers and hardware, the threading path, the brake and feed system, and the controller mode. Crop can also change the required wrap count, which is a separate question from fit. NDSU Extension does note that “net-wrapped bales seem to work better than twine-tied bales due to the coarseness of the material” and that “in most cases, you will need more net wrap or twine when baling corn stalks than for conventional forages” — a qualitative point about the crop, not a statement that any particular roll fits your baler.

How many wraps per bale for corn stover?

Use the current operator manual for your exact machine. At least one manufacturer differentiates by crop: John Deere's manual for the 468, 468 Silage Special and 568 round balers states that “different crops require a different number of wraps for effective baling” and gives minimums of 2 wraps for hay, 3 for straw, wheat hay and cereal grains, and 4 for corn stalks, Sudex, hay grazer and milo stalks. That is scoped to those Deere models — do not carry the figure onto another manufacturer's baler. Deere also notes that bales stored with fewer than two wraps may be damaged by handling or weather, and that a higher monitor setting is needed when machine speed is below rated PTO speed. An earlier version of this article recommended 2.5 to 3 wraps for corn stover, which would fall below Deere's stated minimum of four on those models; that recommendation has been removed.

Do I have to test cornstalk bales for nitrate?

Test before feeding. Corn accumulates nitrate, and NDSU Extension reports that “the lower parts of the corn stalk will have the highest concentration of nitrates” — which is exactly what a baler collects, while a grazing cow takes the leaf first. Drying does not help: University of Nebraska–Lincoln states that “the drying process does not decrease nitrates,” and NDSU notes concentrations do not fall in storage because photosynthesis is required to convert them. Risk rises with drought, frost, hail, disease, prolonged cool or cloudy weather, and high nitrogen or manure history.

How do I sample bales for a nitrate test?

NDSU advises using a bale probe to collect core samples for laboratory analysis, ideally “10% of bales or at least 20 core samples per lot of forage,” where a lot is forage harvested within 48 hours from the same field. NDSU also notes the Nitrate QuikTest “is not designed to evaluate nitrate content in harvested forages.” Check whether your laboratory reports nitrate-nitrogen (NO₃-N) or nitrate ion (NO₃), because the two differ by a factor of about 4.43 and are easy to confuse.

What nitrate level is dangerous?

University of Nebraska–Lincoln reports that for hay “it is suggested that levels above 2,100 ppm NO₃-N are toxic,” and that free-choice feeding above that level is risky even with adaptation because hot spots can deliver more than the lot average. That figure is nitrate-nitrogen on a dry-matter basis, roughly 9,300 ppm expressed as nitrate ion. Interpret your own report with your veterinarian or nutritionist against the class of cattle you are feeding rather than treating a single number as a pass mark.

Does net wrap need to come off before feeding?

Yes, all of it. SDSU Extension states that net wrap and other plastic binding materials “are not digestible in the rumen, so a treatment for [net wraposis] is not available. The best plan is prevention.” University of Nebraska–Lincoln reports that cows fed ground, net-wrapped hay for 140 days in an SDSU study accumulated a softball-sized rumen mass of 0.8 to 1.1 pounds of net wrap, that about 53% of what was offered was recovered, and that Montana State research recovered 47%. Grinding does not solve it: UNL states that “while grinding net wrapped bales may reduce the particle size compared to feeding intact net wrap, health issues can still occur.”

How dry should corn stover be to bale?

NDSU Extension advises that “in most cases, 15% or less moisture is desirable for long-term storage” and that above 15% the likelihood of moulding and spoilage increases. Note that Iowa State's bale-weight formula is stated at 20% moisture — that is the basis for its weight estimate, not a recommended baling moisture. We could not find an Extension source applying a stover-specific spontaneous-combustion threshold, so we are not quoting one.

Can baled cornstalks be a cow's only forage?

NDSU says no: “harvested or baled corn stover should not be utilized as the sole source of forage in winter feeding programs because the harvested material typically contains a greater proportion of stalk and cob, which are less nutritious than the leaf and husk.” Grazed residue is a different feed, because cattle select leaf and husk. NDSU gives average stover composition as 5.0% crude protein and 49.0% TDN on a dry matter basis, and Minnesota reports about 5% crude protein and 50% dry matter digestibility, so supplementation is the norm rather than the exception.

How much residue can I remove without hurting the field?

Iowa State Extension writes that “recent studies suggest that only 20 to 30 percent of the total stover production could be removed for biofuel, based on ground cover requirements to control soil erosion,” while noting that removal guidelines for any given field are “not clear or well documented.” That page also reports a 13-year study where removal cut corn-derived soil organic carbon by 35%. Because it is dated 2007 and framed around biofuel harvest, treat it as a principle and get a field-specific answer from NRCS or your agronomist.

How much stover does a corn crop produce?

University of Minnesota Extension reports that grain and stover yields are related, “typically a 1:1 ratio,” and measured stover production of 3.2 to 4.0 tons per acre, averaging 3.8 tons per acre, across several Minnesota locations at grain yields of 160 to 243 bushels per acre, with about 0.8 tons per acre of cobs. Those are Minnesota figures, so use them for scale rather than as a forecast for your field.

Sources

• NDSU Extension, “Beware of Nitrate Poisoning in Livestock” — highest nitrate concentration in the lower stalk and parts closest to the ground, cattle grazing leaf before stalk, the 6-inch cutter-bar and stubble-height mitigation, nitrite and haemoglobin, abortion risk, drought-stressed oats, barley and corn in North Dakota (ndsu.edu, accessed August 16, 2026).
• NDSU Extension, “Test Forages for Nitrate Before Haying or Grazing” (June 2020) — triggers beyond drought, no decrease in storage, ensiling caveat, bale-probe sampling protocol, QuikTest limitation (ag.ndsu.edu, accessed August 16, 2026).
• NDSU Extension, “Utilizing Corn Residue in Beef Cattle Diets” (AS1548) — stover composition, 15% moisture storage target, baled stover not a sole forage, and the binding and equipment passage: tough and large stalks, specialised balers, more wear and tear on balers, net-wrapped bales working better than twine-tied due to coarseness, and needing more net wrap or twine than conventional forages (ndsu.edu, accessed August 16, 2026).
• John Deere operator manual OMFH309531, 468, 468 Silage Special and 568 round balers, “Setting Number of Net Wraps” — minimum 2 wraps hay, 3 straw/wheat hay/cereal grains, 4 corn stalks/Sudex/hay grazer/milo stalks; fewer than two wraps risks handling and weather damage; monitor-setting chart below rated PTO speed (manuals.deere.com, accessed August 16, 2026).
• John Deere operator manual OMFH313140, 469, 469S, 569 and 569S round balers (N.A.), “Set Number of Net Wraps” — the same crop-specific minimum wrap recommendations in this later model line's manual (manuals.deere.com, accessed August 16, 2026).
• University of Nebraska–Lincoln BeefWatch, “What to do with High Nitrate Forages?” (September 2021) — drying does not reduce nitrate, 2,100 ppm NO₃-N, hot spots, ensiling 40–60%, dilution, supplemental corn, damp-hay warning (beef.unl.edu, accessed August 16, 2026).
• University of Nebraska–Lincoln BeefWatch, “Exercise Caution when Grazing Cattle on Drought Stressed Cornstalks” (2021) — do not turn cows in hungry, supplemental energy (beef.unl.edu, accessed August 16, 2026).
• University of Nebraska–Lincoln BeefWatch, “Hold the Net Wrap and Twine” (2024) — NDSU digestibility work, 140-day SDSU rumen mass, 53% and 47% recovery, grinding does not prevent problems (beef.unl.edu, accessed August 16, 2026).
• SDSU Extension, “Summary of Forage Binding Survey and Current Net Wrap Research” — no treatment available, grinding-removal survey percentages, postmortem recoveries (extension.sdstate.edu, accessed August 16, 2026).
• SDSU Extension, “High Nitrates and Pregnant Cows” — clinical signs, chocolate-brown blood, abortion as first warning sign, sampling (extension.sdstate.edu, accessed August 16, 2026).
• SDSU Extension, “Drought-Stressed Forage: Nitrate Considerations” — fertilisation and manure history, post-rain nitrate rise (extension.sdstate.edu, accessed August 16, 2026).
• University of Minnesota Extension, “Harvesting corn stover” (March 2024) — 1:1 grain-to-stover ratio, 3.2–4.0 tons per acre, measured nutrient removal, composition, baled versus grazed quality (extension.umn.edu, accessed August 16, 2026).
• Iowa State University Extension Ag Decision Maker file A1-70, “Estimating a Value for Corn Stover” — 8–10 lb dry matter per cubic foot, the 20% moisture weight formula, 1,500 lb typical bale, phosphate and potash removal ranges, supplementation framing. This page blocks automated requests, so it is cited without a hyperlink; it is at extension.iastate.edu under agdm/crops/html/a1-70.html (accessed August 16, 2026).
• Iowa State University Extension, “Residue removal and potential environmental consequences” — 20–30% removal ceiling for erosion control, 13-year soil carbon study (crops.extension.iastate.edu, accessed August 16, 2026).
• Iowa State University Extension, “Risk of ear rot and mycotoxins in hail damaged crops” — ear rot and mycotoxin severity, ear rots as a warning sign (crops.extension.iastate.edu, accessed August 16, 2026).
• Ohio State University Extension, “Storing Corn Stover for Biobased Industries” (FABE-6601) — uncovered stack losses and the “more than 17 percent” value reduction, tarping and indoor storage, scoped to six-high rectangular stacks for biofeedstock (ohioline.osu.edu, accessed August 16, 2026).
• Templeton, Scarlata, Sluiter and Wolfrum, “Compositional Analysis of Lignocellulosic Feedstocks. 2. Method Uncertainties,” Journal of Agricultural and Food Chemistry 58(16), 2010 — corn stover Klason lignin of 12.3% of dry weight from 154 replicate analyses (pmc.ncbi.nlm.nih.gov, accessed August 16, 2026).
• Nebraska Extension NebGuide G1846, Wortmann, Klein and Shapiro, “Harvesting Crop Residues” — residue harvest in the context of soil conservation and nutrient removal (extensionpubs.unl.edu, accessed August 16, 2026).

Written by the XES Netting team. We manufacture bale net wrap; we do not sell balers, forage testing, feed or veterinary services. Where we could not find an authoritative source for a claim that appeared in an earlier version of this article, we removed the claim and said so rather than leaving it in place.

Featured photo: Corn shocks, Forestville, Minnesota (2006) by Jonathunder, licensed under CC BY-SA 3.0, via Wikimedia Commons. The photograph shows hand-stooked corn shocks, a traditional harvest method, rather than the baled corn residue this article describes.