Farm & Ranch
[AgriLife Today] Closed-loop concept could be the future of sustainable animal farms
By: Adam Russell
- Writer: Adam Russell, 903-834-6191, adam.russell@ag.tamu.edu
- Contact: Dr. Eunsung Kan, 254-968-4144, eunsung.kan@ag.tamu.edu
STEPHENVILLE – Dr. Eunsung Kan sees his concept of a closed-loop dairy farm, which reuses wastewater, emits zero waste and powers itself on manure, as the future of sustainable animal farming.
Kan, a Texas A&M AgriLife Research chemical and environmental engineer in Stephenville, said his concept could change the way dairies, swine and poultry farms deal with manure, wastewater and greenhouse gasses while utilizing the waste to generate electricity.
Animal waste is a blessing and curse for dairies.
Manure is sold to local farmers who need to infuse nutrients into the soil for crops and forage. However, tons of manure can also be logistically taxing as facilities keep up with the treatment and distribution of large quantities of environmentally problematic materials monitored by state and federal environmental regulators.
Farm operations have been implicated in higher-than-normal levels of nitrogen and phosphorous, antibiotics, heavy metals and hormones in surface and groundwater downstream from facilities. Manure is also a known contributor to greenhouse gas emissions, such as methane and carbon dioxide.
The U.S. Department of Agriculture Natural Resources Conservation Service estimates manure from a dairy milking 200 cows can produce as much nitrogen as is in the sewage from a community of 5,000-10,000 people.
Kan’s research would utilize existing technology – biochar, a carbon material similar to charcoal, created from animal manure and agricultural waste, such as corn stubble or rice straw – that would be used to filter solid waste and effluent. The biochar could be used as a slow-release fertilizer or converted, via pyrolysis, which is the decomposition of organic material by heat, into energy to power the farm.
The closed-loop dairy concept focuses on three main goals – wastewater treatment using dairy manure-derived biochar, producing bioenergy using dairy manure and capturing greenhouse gasses via adsorption onto dairy manure-derived biochar, Kan said.
Biochar has proven to provide a beneficial surface chemistry that can filter a wide range of contaminants, including nitrogen and phosphorous, he said. When the surface of biochar is modified with several methods in a lab, it has shown an ability to capture antibiotics, pesticides, hormones, heavy metals and other possible contaminants.
“The mission is the treatment and reuse of dairy wastewater and the conversion of dairy waste into energy to power the facility,” he said. “It focuses on providing a model for sustainable farming.”
Last year, Kan received a $1 million grant from the Texas A&M University Chancellor’s Research Initiative Fund to research the viability of the closed-loop dairy system. Before joining AgriLife Research, he also received about $400,000 in research grants from the Environmental Protection Agency, U.S. Department of Agriculture and U.S. Geologic Survey to research the concept’s potential to treat animal waste, control greenhouse gas emissions and convert manure to energy.
CONCEPTUAL SYSTEM
The closed-loop dairy is a relatively simple concept, Kan said.
Cows produce manure, which when mixed with remnants of local crops, can become a seemingly endless supply of filtering material, fertilizer and energy.
Columns filled with biochar would act as a water purification system that filters nitrogen, phosphorous and other contaminants from liquid as it passes through, Kan said.
“The affluent from the column would then be very low in nitrogen and phosphorous,” he said. “If we filter to low levels of nitrogen and phosphorus it wouldn’t cause any environmental problem.”
The biochar used to filter nitrogen and phosphorous could then be used as slow-release fertilizer that provides needed nutrients to plants and would not wash away as runoff from heavy rains. In addition, biochar immobilized with photocatalysts would decompose toxic contaminants to harmless products when irradiated by exposure to ultraviolet light.
For instance, Kan’s study has shown that a biochar immobilized with photocatalysts completely degraded antibiotic and hormone compounds while effectively controlling pathogens. The potential for biochar’s use to filter wastewater goes beyond agriculture and could be applied at any wastewater treatment plant, or even to filter contaminants in injection water used in the petroleum industry for fracking.
For energy, dairy manure would be fed into a pyrolysis reactor on site that would use relatively low heat, 500-1,000 degrees Fahrenheit, to create compressed hydrogen and carbon monoxide syngas that can be used to create electric power, Kan said. Excess electricity could be sold to local utility companies. The byproduct from pyrolysis of dairy manure is biochar.
“The principle is very simple,” Kan said. “The dairy would just need a different size reactor to meet its scale of manure output and energy needs.”
Dr. Sergio Capareda, an AgriLife Research agricultural engineer in College Station, proved the pyrolytic conversion of dairy manure to syngas and biochar from his USDA-funded project, Kan said. Kan plans to advance this concept by biologically converting syngas to butanol and bio-jet fuel as alternative transportation fuels, and developing biochar-based processes for wastewater treatment and greenhouse gas control.
Several other researchers and engineers within the Texas A&M system are collaborating with Kan, and interest in the concept is growing among public institutions and private companies.
CONCEPT TO REALITY
Kan will produce a lab-scale version of the closed-loop dairy to determine the necessary scale for application and experimentation at the neighboring Southwest Regional Dairy Center in Stephenville, a privately owned working dairy operated by Tarleton State University used for educational purposes. He hopes to have a system, including the pyrolysis reactor, operating at the dairy within three to four years.
“Having the dairy farm here provides a good opportunity for field data,” he said. “The field demonstrations will help us work out any problems that might arise at the various scales that might be applied by commercial animal farms.”
The dairy produces milk that is processed for consumption and into products such as cheese and yogurt and sold in local grocery stores.
Clay Dameron, the dairy’s waste manager, said between 300-400 cows are milked daily. Those cows produce manure and effluent that is treated via a conventional lagoon system. Around 90-130 tons of solids are moved to nearby croplands and pastures every three weeks where it’s used as fertilizer. Treated liquids from the lagoon are dispersed via sprinklers in nearby fields.
Kan said he believes the closed-loop system will prove to be a logistically and financially viable model for dairy producers to implement in the future. He expects his pilot project at the regional dairy to produce data that will draw more interest and investment from public institutions and private companies.
“It is very exciting,” he said. “I look forward to working with my collaborators and colleagues to make this concept a reality that could change the way dairies operate by providing a self-sustaining, environmentally friendly model.”
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Farm & Ranch
Forage Needs in the Fall
By Savannah Magoteaux
Two bales can look almost identical and feed very differently. Color, smell and leafiness tell part of the story, but a forage test tells you what your cattle are actually being offered. If you buy hay by the ton or are trying to stretch winter feed, that little lab sheet can be one of the cheapest management tools on the place.
Reading the report
Start with dry matter. Hay contains water, and labs report nutrients either “as fed” or on a dry-matter basis. Feeds are easiest to compare on a dry-matter basis because it takes moisture out of the comparison. Hay that is 90 percent dry matter is about 10 percent water.
Crude protein, usually abbreviated CP, is the number most people recognize. It estimates protein from the forage’s nitrogen content. Higher isn’t automatically better. The goal is to match the hay to the animal. A dry, mature cow in mid-gestation doesn’t need the same protein as a lactating cow, a growing replacement heifer or a young calf.
Energy matters just as much. Beef cattle forage reports commonly estimate energy as total digestible nutrients, or TDN. Low-TDN hay may fill a cow up before it supplies enough energy, particularly when her requirements rise late in gestation or during lactation. That is when you may need better forage, an energy supplement or a different feeding plan.
Fiber numbers explain why some hay looks coarse and why animals may not be able to eat enough of it. Neutral detergent fiber, or NDF, is closely tied to intake. As NDF climbs, cattle generally eat less because the forage moves through the digestive tract more slowly. Acid detergent fiber, or ADF, is tied to digestibility. Higher ADF generally means lower digestibility.
Some reports also include relative feed value or relative forage quality. These indexes help compare lots of forage, particularly alfalfa and mixed hay, but they aren’t a complete ration. They don’t replace looking at protein, energy, minerals, animal class and expected intake.
Then come the numbers you hope are boring. Nitrate testing matters when drought, heavy nitrogen fertilization, cloudy weather or other conditions have stressed the forage enough to cause nitrate accumulation. Sorghum-type forages, johnsongrass, corn and some weeds deserve particular attention. Nitrates stay in hay after it is cut and baled, so a risky crop doesn’t become safe just because it dried.
Minerals deserve a look, but this is where a hay report gets harder to interpret. Calcium, phosphorus, potassium, magnesium and other minerals may be listed, yet a complete mineral program depends on water, other feeds and local conditions. A high number isn’t always an advantage. Excessive potassium, for example, can interfere with magnesium use under some circumstances. If you are balancing a ration for high-risk animals, work with a nutritionist or Extension specialist rather than treating the lab sheet as a stand-alone mineral prescription.
Moisture tells another story. Hay baled too wet is at greater risk of heating and mold, and very wet hay can become a fire hazard as microbial activity raises its internal temperature. A test taken months later can’t reconstruct every storage problem, so inspect the stack, too. A musty odor, visible mold, unusual heat and dark discoloration are all reasons to investigate.
Getting a good sample
A hay test is only as good as the sample, and sampling is the step most likely to ruin a good analysis. A handful pulled from the outside of one convenient bale doesn’t represent a stack of 100 bales. Round bales aren’t uniform from the outside to the center, and one bale may not represent the whole cutting.
Texas A&M AgriLife recommends using a hay probe and collecting cores from multiple bales in a lot, then combining them into one representative sample. A coring probe reaches through the layers of the bale and gives the lab a much better cross-section. Test different cuttings, fields or hay types separately, and don’t blend samples from separate fields or cuttings to save the cost of a test if you will feed them as separate lots.
Putting the numbers to work
The most useful way to read the report is backward from the cattle. What class of animal will eat this hay, at what stage of production, and how much is she likely to eat? Once you answer those questions, the lab numbers start to mean something.
A mature dry cow in good body condition can often use lower-quality forage than a first-calf heifer nursing a calf. Young cattle need nutrients for growth on top of maintenance, and cold stress raises energy demand. A hay test becomes valuable when you pair it with those real-world differences.
Remember that price per bale isn’t the same as price per unit of nutrition. A cheap bale with very low energy and protein may require expensive supplementation, and better hay can turn out to be the lower-cost feed once you count waste and supplements.
Before buying, try putting two hay reports side by side. Compare dry matter, crude protein, TDN and fiber first. Then add delivered cost and likely feeding waste. A heavier, denser bale isn’t automatically more economical, and a greener bale isn’t automatically more nutritious. The numbers make the comparison fair.
Testing is especially valuable after a hard weather year. Drought hay may be lower in yield and higher in nitrate risk. Mature, rain-damaged hay may test lower in protein and energy than it looks. Hay cut from a fertilized field after stress may deserve a safety screen before it ever reaches a feeder.
A forage test won’t make poor hay better. It shows you where the gaps are before your cattle show them through lost condition or lower performance. One report can’t answer every feeding question, but it replaces several guesses with measurements, and that makes winter nutrition planning much more accurate.
Farm & Ranch
When Acorns Become a Problem
By Savannah Magoteaux
A heavy crop of acorns under an oak tree usually looks more like a sign of fall than a livestock problem. For most cattle in most years, that is all it is. Trouble starts when acorns stop being an occasional bite and become a meaningful part of the diet.
Oak leaves, buds and acorns contain tannins that can damage the digestive tract and kidneys when cattle eat enough of them. Green acorns are generally considered more toxic than mature brown ones, but either can cause problems if cattle eat too many.
The risk climbs when forage is short and cattle go looking for something else to eat. Drought, overgrazed pastures or simply a heavy acorn crop can set up that situation.
Cattle aren’t equally interested in acorns. A few animals in a herd may eat far more than the rest, which helps explain why cases can appear scattered.
Early signs can be vague. Affected cattle may go off feed, look depressed or become constipated. As the damage progresses, you may see dark or bloody manure, abdominal pain, frequent urination followed by reduced urine output, dehydration and weakness. Kidney failure is the most serious concern.
You can’t remove every acorn from a wooded pasture, so prevention comes down to keeping cattle from relying on them. Adequate forage and supplementation take away the incentive to eat large amounts.
You can also fence cattle away from heavily producing oaks for a while, especially when pasture conditions are poor. If several animals seem to be seeking out acorns, take a close look at the rest of the ration instead of assuming they will quit on their own.
If you suspect oak poisoning, call a veterinarian early. Treatment is supportive and does much more good before severe kidney damage sets in. Moving unaffected cattle away from the source and providing good-quality feed and water may prevent more cases.
Acorns are an important fall food for deer, squirrels and other wildlife, and a few acorns generally don’t spell disaster for cattle. The concern is quantity. A pasture full of oaks becomes a different management problem when grass is short, cattle are hungry and the ground is covered with something they are willing to eat.
Oak toxicity comes up most often in cattle, but other livestock can be affected, too. And the risk isn’t limited to acorns. Oak buds and young leaves also contain tannins, so spring can occasionally bring problems as well. In fall, though, the obvious temptation is lying on the ground where cattle can eat it quickly.
Watch where your cattle spend their time. If cows that normally graze open grass start camping under oaks and hunting acorns, that behavior tells you something.
Walk the pasture, estimate how much usable forage is left and check whether a few dominant animals are eating more than the rest. Hay or supplemental feed may help, but place it where all the cattle can reach it rather than assuming one feeder will solve the problem.
Oak poisoning can look like other illnesses, and no one can diagnose kidney damage from pasture observation alone. A veterinarian may use history, clinical signs and lab work to separate it from dehydration, digestive disease or other toxicities. That is another reason to mention a heavy acorn crop when you call. A detail that seems like an ordinary part of fall can be an important part of the history.
Your pasture plan doesn’t have to be complicated. If one wooded trap has a much heavier acorn crop than the rest, use another pasture while you still have the choice.
If you can’t move the herd, make sure hay and supplement are adequate before the animals get hungry enough to seek out acorns aggressively. Salt or mineral by itself won’t make up for a shortage of forage.
The problem usually fades as cattle eat through the crop or the acorns weather or get covered. Don’t return cattle that have already shown signs as soon as they look better, though. Kidney injury can be serious. Follow your veterinarian’s recommendations and reassess the pasture before turning recovered animals back out.
Farm & Ranch
Land Market Report
By Jared Groce
Late summer has been brutal on our livestock, our grass and the rural land market in North Texas. We currently have an astounding 42 months of inventory on hand in our report area, and the only properties selling are the ones priced right. Overpriced properties aren’t even getting looked at, much less receiving offers, so pricing your property correctly matters more than ever right now.
Many sellers are still picturing the daily price increases we saw in 2020 to 2023, but those days are behind us, and agents need to be more realistic with listing prices to get any activity for their clients. Hopefully the rains will come soon and bring more land buyers with them this fall, but right now it is still very much a buyer’s market. No one knows how long this dry spell will last, but it will likely take a flood to end it. The same is true of the weather!
They say the best time to plant a tree, or buy land, was 20 years ago, and the second-best time is today.
| County | Area | Acres | $/Acre | List Price | Sold Price | Sale/List | DOM |
|---|---|---|---|---|---|---|---|
| Clay | Henrietta | 120.07 | $5,150 | $714,000 | $618,309 | 86.60% | 434 |
| Clay | Bellevue | 159.44 | $6,184 | $981,000 | $985,959 | 100.50% | 48 |
| Clay | Henrietta | 293 | $4,982 | $1,538,250 | $1,459,600 | 94.90% | 212 |
| Clay | Average | 190.84 | $5,438 | $1,077,750 | $1,021,289 | 94.00% | 231 |
| Collin | Anna | 11.08 | $84,356 | $1,200,000 | $935,000 | 77.90% | 634 |
| Collin | Average | 11.08 | $84,356 | $1,200,000 | $935,000 | 77.90% | 634 |
| Cooke | Muenster | 11 | $18,000 | $209,000 | $198,000 | 94.70% | 250 |
| Cooke | Gainesville | 19.3 | $16,580 | $345,000 | $320,000 | 92.80% | 541 |
| Cooke | Valley View | 96.23 | $15,500 | $1,679,215 | $1,491,565 | 88.80% | 194 |
| Cooke | Average | 42.18 | $16,693 | $744,405 | $669,855 | 92.10% | 328 |
| Denton | Sanger | 16.46 | $39,422 | $649,000 | $649,000 | 100.00% | 47 |
| Denton | Cross Roads | 10.35 | $97,575 | $1,200,000 | $1,010,000 | 84.20% | 40 |
| Denton | Sanger | 300 | $14,000 | $4,999,999 | $4,200,000 | 84.00% | 1,327 |
| Denton | Aubrey | 74.09 | $57,684 | $4,815,525 | $4,273,550 | 88.70% | 302 |
| Denton | Average | 100.22 | $52,170 | $2,916,131 | $2,533,138 | 89.20% | 429 |
| Grayson | Collinsville | 11.61 | $46,516 | $600,000 | $540,000 | 90.00% | 280 |
| Grayson | Van Alstyne | 18.8 | $58,511 | $1,175,000 | $1,100,000 | 93.60% | 280 |
| Grayson | Whitesboro | 30 | $37,984 | $1,170,000 | $1,139,506 | 97.40% | 277 |
| Grayson | Average | 20.14 | $47,670 | $981,667 | $926,502 | 93.70% | 237 |
| Jack | No sales reported | — | — | — | — | — | — |
| Montague | Montague | 485 | N/A | $5,566,000 | N/A | N/A | 333 |
| Montague | Bowie | 26 | $12,244 | $323,500 | $318,352 | 98.40% | 743 |
| Montague | Montague | 37.3 | $10,327 | $428,950 | $385,195 | 89.80% | 1 |
| Montague | Saint Jo | 1,185 | $7,764 | $10,000,000 | $9,199,829 | 92.00% | 19 |
| Montague | Average | 433.33 | $10,112 | $4,079,613 | $3,301,125 | 93.40% | 274 |
| Wise | Sunset | 12 | $19,027 | $234,000 | $228,320 | 97.60% | 16 |
| Wise | Sunset | 12 | $19,027 | $234,000 | $228,320 | 97.60% | 14 |
| Wise | Chico | 11.44 | $24,476 | $299,000 | $280,000 | 93.60% | 24 |
| Wise | Chico | 10.25 | $29,265 | $315,000 | $300,000 | 95.20% | 12 |
| Wise | Average | 11.42 | $22,949 | $270,000 | $259,160 | 96.00% | 17 |
DOM = days on market
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