Soil Conservation District Secretary, Elizabeth Gibbs
NRCS Dictrict Conservationist, Martha Griffin
Clover adds yield, nutritional quality to pasture
Clover adds yield, nutritional quality to pastures
Clover adds yield, nutritional quality to pastures
MT. VERNON, Ill. — Legumes in pastures improve forage quality, increase animal gains and reduce fescue endophyte effects.
“The clover dilemma is if there is enough clover in the field for high yields and if there are broadleaf weeds in the pasture should they be sprayed to kill them,” said Jimmy Henning, University of Kentucky Extension professor.
“Clover can extend grazing over grass alone and often times it gives you more yield in the summer,” Henning said during a presentation at the Heart of America Grazing Conference. “And it will reduce the nitrogen fertilizer cost though nitrogen fixation.”
It is important for graziers to determine how much yield they need from their pastures for their livestock before deciding if they have enough clover to withhold nitrogen fertilizer.
Henning discussed research that evaluated yields from forage and the nitrogen transfer in mature alfalfa and grass pastures. “In five- to six-year pastures, the yields increased as the alfalfa increased from 11 to 55%,” he added.
“The yield is going to be more correlated to the legume content of last year,” he said. “There is not much direct transfer of nitrogen in season from the legume to the grass.”
A study in Virginia compared the dry matter yield of three systems — fescue and nitrogen, fescue and red clover and fescue and alfalfa.
“They were able to duplicate the yield with fescue and clover and increase the yield with fescue and alfalfa,” Henning said. “We can make fields of grass and clover yield like grass and nitrogen, but it takes a lot of legumes to do that.”
How long the clover has been in a pasture impacts yield. When comparing a newly seeded grass and clover pasture to a long-term stand of grass and clover, Henning said, for the long-term stand, the yields peak out at about 30% legume, however with the new stand, yields continue to increase all the way to 80% legume.
“Actual yield tonnage depends on the productivity of the legume,” he noted.
“You may choose to apply moderate rates of nitrogen in the spring even if the stand has clover in it,” Henning said. “It doesn’t kill the clover but the clover will take a break and when the nitrogen goes away the clover will start the factory again.”
But, the speaker added, don’t put nitrogen down at the same time clover is being established.
With a grazing system, the clover, grass, livestock, roots, nodules are all interacting and the nitrogen flows throughout the system.
“The legume is pulling the nitrogen out of the air and there is the decay of leaves, dead roots and sloughing of nodules,” he said. “The majority of the nitrogen is going through the cow and coming out its back end, so feeding the grass nitrogen from legumes takes time.”
Alfalfa can fix 150 to 300 pounds of nitrogen per acre per year and both white and red clover are similar, Henning reported. “From 80 to 90% of that is excreted through the animal as manure and urine,” he added. “The manure contains nitrogen and phosphorus and the urine is nitrogen and the majority of the potassium.”
About 50% of urinary nitrogen is lost through volatilization, Henning said.
“From 14 to 22% of the area of the pasture is covered with manure and urine so the grazing system is going to have a great impact on the ability of getting nitrogen flowing through the system. With continuous or low stocking rates, more nitrogen is concentrated around the loitering areas like the fence, shade or waterers.”
When a rotational grazing system is utilized, the nitrogen distribution in the pasture is improved. The goal, Henning said, is higher stocking rates with shorter grazing duration. “The No. 1 pathway of nitrogen transfer from legumes to grass is through grazing livestock,” he added.
“The increase in yield in mixed stands comes from the legume,” Henning stated. “For high yields we need 25 to 30% legume by weight in the pasture, year after year.”
Microbes could be used by farmers as natural fertilizer for poor soil
Microbes could be used by farmers as natural fertilizer for poor soil
A study published in The ISME Journal identified 522 genomes of archaea and bacteria associated with the roots and soil of two plant species native to the Brazilian montane savanna ecoregion known as campos rupestres ("rocky meadows"). Hundreds of microorganisms hitherto unknown to science were identified, showing that the ecoregion is a biodiversity hotspot and that many new organisms have yet to be described and classified in Brazil.
The discovery could potentially be a basis for the development of biological substitutes for the chemical fertilizers used by farmers, especially those containing phosphorus.
"Phosphorus is normally present in the soil, but not always in a form that plants can use. Most of the microorganisms we found make phosphorus soluble so that plants can absorb it," said Antônio Camargo, first author of the article.
The study was conducted under the aegis of the Genomics for Climate Change Research Center (GCCRC) in partnership with the Brazilian Agricultural Research Corporation (EMBRAPA) at UNICAMP.
One of the plants, Vellozia epidendroides, lives in shallow soil, whereas another, Barbacenia macranta, was found growing on exposed rock. Both belong to the family Velloziacea. Specimens were collected in a private area adjacent to the Serra do Cipó National Park in Minas Gerais state.
A comparison of microorganisms associated with plants found growing in soil and on rocks showed that they comprised different communities but shared many species. Several microorganisms were highly specialized in phosphorus transport and conversion to the soluble form of the mineral, which plants can absorb.
"Microbial communities also play an important role in supplying nitrogen, another essential plant nutrient," said Camargo, currently a researcher at the US Department of Energy's Joint Genome Institute, where the genomes were sequenced.
Novel solutions
"Previous research focused on plants' mechanisms for adapting to the harsh conditions of this montane savanna and often ignored microorganisms. Our study shows that microorganisms can play a key role in plant adaptation to the extreme conditions of this environment. In particular, they supply the phosphorus need to fuel plant growth," said Rafael Soares Correa de Souza, one of the corresponding authors of the article.
The researchers expect their discoveries to contribute to the creation of products that replace chemical fertilizers based on phosphorus, one of the crop nutrients most widely used by Brazilian farmers. More than half the phosphate fertilizer used in Brazil is imported, mainly from Morrocco but also from Russia, Egypt, China and the United States.
In addition to the dependence on imports, phosphate fertilizer pollutes water bodies, and its production is a source of greenhouse gas emissions, estimated at 1 kg for every kg of fertilizer produced. Moreover, phosphorus is a non-renewable natural resource and hence finite.
Biological fertilizers are already in use in Brazil. In the case of soybeans, they are the main source of nitrogen in 80% of the planted area. A previous study by the GCCRC estimated that the use of biological inoculants instead of nitrogen fertilizers could save USD 10 billion per year.
"The study also underscores the need for conservation of Brazil's ecosystems, which can supply many other nature-based solutions like this one," said Souza, a co-founder of biotech startup Symbionics, which develops next-generation biologics.
As noted, campos rupestres are biodiversity hotspots with many exclusive species. They form mosaics totaling some 26,500 square kilometers scattered across Brazil in biomes such as the Cerrado (savanna), Caatinga (semi-arid areas in the Northeast) and Atlantic Rainforest. The main threats to these ecosystems are mining and cattle raising.
The researchers are now conducting studies to test the benefits of some of the microorganisms found in croplands. Experiments are under way at the GCCRC in Campinas.
Alternative Forages:
Specialist looks at different options
Kansas State University’s Beef Systems Specialist Jaymelynn Farney is investigating how cattle choose what to eat.
Farney, who is at the Southeast Research and Extension Center in Columbus, Kansas, has been performing studies on what forages cattle prefer. She’s using summer cover crops, or annual forages, in re-purposed protein tubs. They’re then offered to cattle to determine preference.
“I have grown eight plant species in each growing period and offered the plants to the cows in two 24-hour sessions,” she said. “We recorded their behavior for the first hour after introduction to the plants and they were video recorded through the remainder of the time to see which plants they completely consumed and in which order.”
The study wants to help producers make decisions about which cover crops to plant when incorporating grazing.
“There is a laundry list of plants that contain useful cover crop benefits and it becomes daunting to select the species that will meet your operation’s objectives,” Farney said.
When deciding what plant species to sow, Farney said there are two trains of thought.
Purposefully plant only those species that cattle will consume to maximize land usage or gains along with capturing some cover crop benefits; or
Strategically plant species that cattle are averse to in order to leave appreciable biomass in the field for soil health objectives.
“With these two things in mind I was interested in seeing how cattle that were completely naive to cover crops consumed these plants,” Farney said.
Initially, Farney has found the most preferred plants include: Barley, Austrian winter pea and Graza forage radish (tie), mustard, Impact collard, Trophy rape, and purple top turnip (all fairly the same in preference). Last was Bayou kale. Her preference information was collected prior to a freeze.
“Stay tuned to next year to find out what their preference to these same species are when grazing after a killing freeze,” Farney said.
For summer grazing, in order from most preferred to least includes: Brown mid-rib forage sorghum and sorghum-Sudan (tied for first), pearl millet, Black oil sunflower and sun hemp (tied for third). Least favorite with little to no difference (strongly objected) were mungbean, okra and safflower.
Farney said there is some learning in both the cattle and the researchers associated with these summer grazing plants.
“The first day exposed nearly all the cows did not even try the okra, but the second day they consumed them before mungbean and safflower,” Farney said. “Another interesting comment about the summers, all grazing occurred when the sorghums were 2 feet tall to minimize prussic acid issues.”
For the sorghums, grazing occurred 35 days after planting. The sunflowers in that time frame were very small and immature (6 to 8 inches tall at the most) while the mungbean and okra had leaves that were over 7 inches in diameter.
“Preference studies become difficult to quantify as cattle do learn and modify grazing behavior especially after that first introduction to new plants,” she said.
When in drought
Farney suggests spending some time to determine the plant species with more drought tolerance.
“I would stay away from really expensive components of mixtures because there is a greater chance of crop failure with no moisture,” she said. “There is some literature that shows that a few different plant species as a cover crop have some environmental lee-way.”
For stocker cattle
Farney leans heavily on the grass component of a stocker cover crops plan.
She limits brassicas to a 1 pound per acre with maximum of 1.5 pounds of brassica seed per acre. Amounts over this can cause the brassicas to outcompete the grass species and reduce grass tonnage. For fall forages, the grass and brassica species offer enough protein to the animal.
“Younger calves have a stronger aversion to the broadleaves and brassicas than cows do and this can potentially hamper gains for a short duration until they begin to consume these plants,” Farney said
“In Kansas, from my research and measuring producers fields, we rarely get any fall growth of legumes,” she said. “This is an expensive component of the mixture and with the combination of low to no-growth and no need for additional protein to meet calf requirements, I do not include legumes in fall covers.”
Farney suggests oats and barley—both spring and winter varieties—to those looking to graze something other than native grass as they offer the earliest, quickest growth. Triticale is intermediate and wheat and rye will have the majority of their growth late winter and early spring. Turnips and radishes have a very rapid growth rate, but once a freeze happens, they don’t generate any more dry matter. Grass species continue to have some growth as the season goes on.
Managing the meat
During and through a drought, the reduced availability of forages hurts stocker producers the most.
“If forage is severely limiting, alternative methods of growing these calves need to be implemented,” Farney said.
She said Dale Blasi at the K-State Stocker unit has been doing interesting research that shows that limit feeding stocker calves can be a viable management strategy.
“These calves gain as well as contemporaries on less feed,” Farney said. “This allows us to stretch our forage and feed base.”
With the option of several high energy feedstuffs, when limit fed and balanced in the ration become an economical option to forage only, especially at elevated prices due to low supply and high demand.
“Substitution is another thing to consider with stockers,” Farney said. “We are essentially wanting to feed more of something else so they eat less grass or hay.”
Corn has commonly been identified as the culprit of reducing free-choice hay and grass consumption, according to Farney. A general rule of thumb for supplementing corn is 0.3 percent of the animal’s body weight or less will not reduce forage consumption. A level above that can reduce it. At 0.75 percent of body weight, for each pound of corn they will consume one pound less forage on a dry matter basis.
“It is still important to make sure to meet protein requirements,” Farney said.
Tennessee's farmers care for the landscape with no-till farming