Signs of Rill Erosion in No-Till and Tilled Fields

Keen observers have noted signs of rill erosion in crop fields. Do we still need conservation practices like grassed waterways and strip cropping to control these?

Reports have been coming in of rill erosion in crop fields. In some cases these rills are transformed into gullies. These fields may be in previously tilled or no-till fields. Rills are the result of concentrated flow cutting into the soil and carrying soil away with runoff. If nothing is done to heal them rills degrade into gullies.

The difference between rills and gullies is that rills can still be crossed easily with farm equipment, but gullies cannot. Rills can easily become gullies in no-till field because the rills are not filled in and in the next runoff event the runoff cuts in a bit more. However, tillage doesn’t solve the problem of concentrated flow runoff, but just covers up its effects – rills will form again next year if concentrated flow occurs.

Here are some tips to avoid rill erosion:

  • Rill erosion can only happen if there is surface runoff. So first of all, we need to use practices in the field that help maximize infiltration. This includes permanent no-tillage, vigorously growing multi-species cover crops, deep-rooted bio-drilling crops, close-growing crops, planting on the contour, heavy mulch cover, perennial grass and forage crops, manure and compost, and avoiding compaction to name just a few.
  • However, even if farmers use all these practices, water may still run off occasionally. During the spring, summer and fall, rainfall events may be so intense that they exceed infiltration capacity on a very healthy soil. Climatologists tell us that these heavy rainstorm events will become more common in our state. So we have to be ready for “the Big One” at all times by armoring the soil with crop residue and living cover and, below ground, live root systems to hold the soil in place.
  • Strip cropping still makes sense, even if no-tillage is used. To alternate strips of annual crops with perennial sod planted on the contour helps stop runoff from creating rills that might form in the annual crop strips. The strips just don’t have to be as narrow as they were in the tillage days because of the improved soil health and increased infiltration in the no-till annual crop strips.
  • Runoff can also form when the subsoil is frozen but the topsoil is already thawed – the water will just not infiltrate when the pores are all full with ice! Additionally, we have soils that have natural impervious layers, such as fragipans. Water ponds on top of these layers leading to a seasonally high water table. Once the top of the water table reaches the soil surface, water will run off, no matter how healthy your soil is. Where this water commonly collects in the landscape to form concentrated runoff, it is really beneficial to have grassed waterways. The grassed waterways have perennial sod-forming grasses that grow in the summer to create a dense matt and fibrous root mass underground to protect the soil in the winter. My experience is that annual cover crops planted after summer crops often don’t have enough time to develop to provide the same cover as a permanent sod on soils with seasonally high water tables where the cover crops drown out.
  • Finally a word about maintenance of grassed waterways. Grassed waterways need annual maintenance and also to be checked periodically. Annual maintenance includes mowing the waterways about two times a year to keep the vegetation short and promote sod-forming vegetation to tiller for soil protection. To keep the grass short in the waterway is important to avoid soil carried in runoff to settle out all at the edge of the waterway. This will quickly lead to formation of a ‘bund’ at the waterway edge which will block water entry into the waterway – instead water will start running parallel to the waterway creating a rill (or gully!) on the edge of the waterway. Bund-formation at the edge of the waterway is inevitable but can be slowed down by mowing the vegetation in the waterway from time to time. After several years, however, some maintenance is needed to remove the bunds – this is an opportunity to enjoy some recreational tillage with a disk to level the edge of the waterway. Don’t forget to reseed the disturbed zone so your grassed waterway does not loose its effectiveness.

It is important to keep good care of our soils, which includes eliminating the scar of rill erosion on our farms.

(Source -https://extension.psu.edu/signs-of-rill-erosion-in-no-till-and-tilled-fields)

Read more

Winter green manure – advantages and disadvantages

What is ‘green manure’?

Digging in green manure

By ‘green manure’ we don’t mean manure from a very poorly horse… we mean that we sow a cover crop in a bed (or beds) with the sole purpose of letting it grow before we cut it down and turn or rotovate it into the soil (without harvesting any produce from it). Think of it as a sacrificial crop used to improve your soil – it sounds a bit bonkers but there are many reasons why we do it. An Autumn sowing of green manure will see plants grow throughout the winter before they are cut back and turned into the soil the following spring.

Green Manure Advantages:

  1. Some green manure crops can fix nitrogen and key soil nutrients into the soil so that they don’t leach out of the soil over the cold rainy autumn and winter months. Empty beds will leach nutrients.
  2. Other green manure crops can bring up nitrogen and minerals from deep in the soil into the plant foliage, which when cut back and rotovated, adds them into the soil for Spring planting.
  3. Green manure crops restrict weed growth, empty beds are likely to be overtaken by unwanted weeds which will draw nutrients from the soil and be a nuisance to remove the following year.
  4. Many green manure crops can help to break up heavy clay soil, those crops with a long tap root help to split large clumps of clay, making the soil easier to manage and cultivate.

Green Manure Disadvantages:

  1. A green manure crop may provide an environment for slugs and snails to breed in, which could increase their numbers (but then again so could weeds!).
  2. You have to allow up to four weeks after cutting back and rotovating the green manure crops before sowing a new crop. This is because some crops are allelopathic which means they naturally leave toxic substances in the soil to restrict the germination of other new crops. (NOTE. Coffee grounds also do this because of the caffeine!).
  3. Some varieties of mustard are commonly sold as green manure cover crops. Mustard is a brassica so if you are planning to grow cabbages, broccoli or cauliflowers in a bed it should not have been recently used to grow a mustard cover crop.

 

Landsberger Winter Mix

Landsberger Winter Mix

Personally I only ever sow green manure crops in mid Autumn to provide over-wintering benefits but you can sow many of them all year round. Since I typically need my allotment beds throughout spring and summer that rules out a green manure solution for me in peak growing season. Here below I have listed some common ‘Autumn sowing’ green manure crops but there are spring and summer sowing crops available with a bit of research. You can get away with sowing winter green manure crops through until around mid October, I once tried a November sowing of rye but that didn’t germinate very well:

  • Italian / Hungarian Grazing Rye – a nitrogen and mineral LIFTER that also works well as a soil structure improver. Can be left to grow for up to two years before cutting (if you feel like a year off at the allotment!).
  • Red Clover / Trifolium incarnatum – a nitrogen FIXER that also works well as a soil structure improver and is an excellent weed suppressant.
  • Forage Pea – a legume which is again a nitrogen FIXER and improves soil structure with its deep root system.
  • White Mustard (Sinapsis alba) – a fast growing brassica which covers the ground in just over one month. Mustard plants can ‘cleanse’ the soil of pathogens because they contain high levels of glucosinolates.
  • Winter Field Beans – a nitrogen FIXER, very hardy and excellent for breaking up heavy soils

(Author –BY Matt Peskett)

Read more

Is Nitrogen-Fixing Corn the Future?

Nutrient-rich soils spoil corn—in fact, so much nitrogen is present in the soil, a function that would have made microbes fixate corn nitrogen has shut off. Ever since, farmers have applied ton after ton of nitrogen to the soil to ensure hybrids perform to their potential.

“Fertilizer is the lifeblood of which yields can be realized—it’s what makes discovering the genetic potential of the seed possible,” says Karsten Temme, co-founder and CEO of Pivot Bio. “At Pivot we’re trying to unlock the crops’ microbiome—we’re realizing there are microbes that are able to fixate nitrogen for corn, not just for soybeans.”

The company ran field tests on their new microbial product called On Technology in the Midwest in 2017. Yield results aren’t available yet so time will tell the true effect.

On Technology complements a farmer’s nutrient program—it doesn’t mean he can forego nitrogen application for the year.

Temme says the product will fill in nitrogen shortcomings throughout the season, which will be especially beneficial between nitrogen applications when the plant is at risk of running short. On Technology adds anywhere from 25 lb. to 50 lb. of nitrogen per acre.

The product can be applied as a seed treatment or in-furrow. Unlike rhizobia, which help soybeans fixate nitrogen, the microbials used in corn don’t create nodules. Instead the microbes surround the roots, grow with the roots and provide nitrogen at all parts of the root.

“We’re breaking new ground because any microbes that have the potential to fixate nitrogen in cereals just aren’t doing it in any meaningful way because of the nitrate in the soil now,” Temme explains. “Our technology interacts with those microbes and identifies, characterizes and fine-tunes microbes to realize their full potential—adjusting the genetic material naturally present in a microbe to increase nutrient uptake by the crop.”

The company says these microbials will not only fixate nitrogen but also increase yield by letting the crop take up more nitrogen when needed.

“Growers face a tough challenge because corn needs a lot of nutrients. The biggest problem is rate,” Temme says. “The rate that corn needs nitrogen is faster than the mineralization of organic matter. Supplementing with microbial nitrogen fixation can unlock a lot of yield potential.”

“Next summer is what will be the first version of our product—the ‘real’ commercial, generation one product, in the hands of growers and corporate partners,” Temme says. During field testing, the company will document what’s happening in the field, including visual differences in the plants and roots and yield differences.

Adding 25 lb. to 50 lb. of nitrogen per acre is substantial, but the company would like to see that number increase and expects the product to evolve in the future. Pivot Bio wants to partner with farmers to establish more trials in 2018 and plans to use On Technology soon in other crops such as wheat, sorghum and rice.

“We’re excited to connect with anyone who wants to develop something that helps transform nutrient management,” Temme says. “On Technology will be beneficial financially by reducing potential nitrogen loss and increasing efficiency—all while complementing good stewardship.”

Nitrogen Management is a Year-Round Commitment

When and how you apply nitrogen is a decision that revolves around efficiency and stewardship. “This is the time to sit down with your retailer, look at your cropping systems and see what will be best for you when it comes to spring versus fall-applied nitrogen,” says Tom Fry, sales manager of premium products with The Mosaic Company. “The decision is a function of multiple factors—cropping systems, typical fall and spring soil conditions, the market and logistics.”

What fall applications can offer in potentially lower prices and more favorable weather can be for naught. “Every study I see shows spring-applied nitrogen results in better yields than fall application,” says Darin Lickfeldt, Verdesian senior technical development manager. “You stand to lose nitrogen by volatilization, leaching or denitrification. Applying 100% of nitrogen in the fall is a risky business that relies on hope, not science.”

Nitrogen loss should be top of mind year-round, and the most sustainable way to apply nitrogen is in multiple passes.

“If you apply 150 lb. of nitrogen as urea and lose one-third of it with a spring application, let’s say that’s $20 per acre with current urea costs,” Lickfeldt says. “If it costs about $5 per acre to run a sidedress rig across of the field, you’re still money ahead to apply a second time versus save a trip.”

Take that same concept and compare it with your actual machinery costs—if it’s less than $20 per acre you’re money ahead to sidedress. You can also compare what it cost to run across the field a second time with a nitrogen additive that will keep it safer in the soil longer—if the additive is more than $20, sidedressing might again be the better option.

“We encourage farmers to start planning now with soil sampling to get a baseline on phosphorus and potassium,” Fry says.

However, mobile nutrients aren’t well represented in the zero to six test. Farmers considering split nitrogen applications with an in-season nitrogen application might want to consider taking a 2′ in-season test to more accurately assess available nitrogen to fine-tune application rates.”

To make sure you don’t apply too much lime, consider how in-season applications can cause temporary acid swings in pH.

Weigh your options now when considering nitrogen timing. The right or wrong choice is critical to nutrient availability and ultimately your success.

(By -By Sonja Begemann, source – https://www.agweb.com/article/is-nitrogen-fixing-corn-the-future-naa-sonja-begemann/)

Read more

Corn Silage Showing High Levels of Mycotoxins

Corn silage samples from across the country are showing extremely high levels of mycotoxins, particularly deoxynivalenol (DON), type A trichothecenes (T-2), fusaric acid and fumonisin.

That’s according to samples analyzed by Alltech. Corn crops grown in mono-cropping, reduced or no-till systems seem particularly vulnerable. Barlage and haylage samples are also showing multiple mycotoxins this year, including DON, T-2, fusaric acid and fumonisin. Corn grain samples are showing signs of DON, fusaric acid and fumonisin.

“Understanding the risk of mycotoxins and combinations of mycotoxins, even at lower levels, allows livestock owners and managers to institute a management program for optimum performance and health,” says Max Hawkins, a nutritionist with Alltech’s Mycotoxin Management Team.

Testing feedstuffs as soon as possible is the first step in knowing if you have a potential problem with this year’s crop. The next step is working with your nutritionist to develop a plan to mitigate any problems that you have.

(Source – https://www.agweb.com/article/corn-silage-showing-high-levels-of-mycotoxins/)

Read more

Corn Genetics Research Exposes Mechanism Behind Traits Becoming Silent

For more than a century, plant geneticists have been studying maize as a model system to understand the rules governing the inheritance of traits, and a team of researchers recently unveiled a previously unknown mechanism that triggers gene silencing in corn.
Gene silencing turns off genetic traits, an important consideration for plant breeders who depend on the faithful inheritance of traits from one generation to the next.
Gene silencing can cause genes to not express, losing those traits in the final cob. The pattern of pigmentation on the corn kernels and the cobs depends upon the position of the pericarp color 1 gene, and whether it is silenced.
Historically, the maize p1 gene has been used as a model by maize geneticists. Previous researchers did not know that two types of overlapping DNA methylation marks could modify, silence or activate this gene. The discovery adds to geneticists’ knowledge of different mechanisms of non-Mendelian inheritance, according to lead researcher Surinder Chopra, professor of maize genetics, College of Agricultural Sciences, Penn State.
In findings reported in PLOS One, Chopra’s team showed that silencing the corn pericarp color 1 gene — regulator of the kernels’ outer layer color and the cob color — can have two “overlapping” epigenetic components — RNA dependent DNA methylation (RdDM) and non-RNA dependent DNA methylation (non-RdDM).
In corn, the pericarp color 1 gene regulates the creation of brick-red flavonoid pigments, as seen on the left-hand side of this corn cob.
“DNA methylation, which is the addition of methyl groups to the DNA molecule, can change the activity of a DNA segment without changing the sequence,” he said. “DNA methylation typically acts to repress gene transcription, which is the first step of gene expression.”
In plant cells, when and at what level a gene is expressed is under tight control between transcription activation and suppression, Chopra explained. Small RNAs — molecules essential in regulation and expression of genes — can mediate methylation of DNA strands and shut down transcription activity, therefore playing a role in silencing inherited genes or transgenes introduced to produce desirable crop traits.
In corn, the pericarp color 1 gene regulates the accumulation of brick-red flavonoid pigments called phlobahpenes. The pattern of pigmentation on the corn kernel pericarp and “glumes” — membrane covering the cob — depends upon the expression of the pericarp color 1 gene. Some examples of these patterns are: white kernels, red cob; red kernels, red cob; variegated kernels, variegated cob; red kernels, white cob; and white kernels, white cob.
“Our study on maize pericarp color 1 gene has demonstrated the involvement of both small RNA-dependent and small RNA-independent mechanisms for gene suppression,” Chopra said. “This study reveals the additional layer of gene regulation by small RNAs, and improves our understanding of how gene expression is regulated specifically in one tissue but not in the other.”
Typically, when plant breeders are creating new types of cultivars, several traits they are breeding for may disappear or their expression gets reduced in the progeny, he said. “And that, we now know, is because of gene silencing.”
A better understanding of how gene-silencing mechanisms cause the disappearance of desired traits has long been needed, Chopra believes. It can be disastrous for a farmer to buy seeds that do not behave in the grow-out the way they were promised by the producer.
If one or more genes that are controlling a trait become silent due to overlapping DNA methylation, then that trait basically disappears from the population.
“That is a big setback for anyone trying to breed for traits such as high yield, which is regulated by several genes,” said Chopra. “If one or two of those genes that are essential for high yield become silent, then a reduction in the overall yield may result.”
Also involved in the research were two doctoral students advised by Chopra in Penn State’s Department of Plant Sciences: Po-Hao Wang, who is currently working as a scientist with Dow Agro Sciences, and Kameron Wittmeyer; Blake Meyers, with Donald Danforth Plant Science Center, St. Louis, Missouri; and Tzuu-fen Lee, a post-doctoral fellow from Meyers’ lab in the Department of Plant and Soil Sciences at Delaware Biotechnology Institute, University of Delaware, who is currently employed by Pioneer Hi Bred International Inc.
The National Science Foundation supported the research.
(Source -http://www.farms.com/news/corn-genetics-research-exposes-mechanism-behind-traits-becoming-silent-129587.aspx)
Read more

Are You a Precision Grower

Are you a “precision grower”?

Don’t answer this question too quickly. Some specialty crop growers are steeped in cutting-edge technologies yet don’t see themselves as being practitioners of precision agriculture. Conversely, there are thousands of row crop growers in the U.S. using fairly commonplace technology – GPS-guided autosteer, for instance – who consider themselves precision adopters.

So who’s right, and who’s wrong?

To answer this question, we must get to a durable definition of precision agriculture that is specific enough to distinguish between real users and non-users, yet is at an altitude high enough to transcend multiple crop areas and constantly evolving technologies. At Meister Media, we feel precision programs are as real for specialty crop growers they are for row crop growers. Let me tell you why.

An Enduring Definition of Precision

More than 20 years ago, a representative of a high-tech defense contractor that was vitally interested in entering ag markets gave me an in-person demo of GPS in action. It was a memorable experience, yet his definition of precision agriculture was equally unforgettable. “It’s really all about use of data,” he told me then. “Data gathering, data analysis, and data application – that’s it.”

I believe this definition of precision agriculture remains largely valid today, and it’s expressed in the accompanying chart that is guiding our ongoing coverage of PrecisionAg® Cotton. By our definition, a true precision grower must do all three of the following:

Data gathering (G). This once was mostly about grid soil sampling and yield monitors in row crops. But in today’s specialty crops, we have imagery from drones and airplanes and satellites, data from soil sensors and moisture sensors, sophisticated weather forecasting, and on and on. The list of data sources is now nearly endless, but it’s also nearly useless if there isn’t …

Data synthesis and analysis (Syn-An). In the early days of precision, this often meant one-dimensional colored field maps of, say, yield and fertilization. But today’s sophisticated farm management software platforms can house dozens of data points and layer them so that a grower, agronomist or consultant can compare, contrast, and analyze the data to their heart’s content. How did X variety do in field X in a rainy season with heavy insect pressure and light nitrogen application? Such programs can theoretically give you that answer.

Data application (Appl). Data gathering, synthesis, and analysis are moot if the wisdom they represent doesn’t reach the field – e.g., if the variable-rate planter breaks down, or if the hi-res camera installed to monitor pest populations and regulate the release of mating disruptors misfires. In fact, I think precision is soon going to see a resurgence in the design and engineering of practical field application tools.

In the meantime, I do think a fourth dimension of technology merits consideration in any precision grower’s operation:

Postharvest (PH). Technology, data, and connectivity – vital to linking up and giving the full picture to in-field production – are extending as well to packinghouse automation, to storage and transport sensors, and to the traceability/sustainability programs that are increasingly favored by large food manufacturers and retailers.

“Moneyball” for Agriculture

You ask: But haven’t we growers been doing all this all along – gathering, analyzing, and applying information?

You have. But here’s an analogy. Precision agriculture rightly has been compared to “Moneyball” in sports. Baseball scouts long have collected data on players and analyzed it and used it to make batting orders or draft-day decisions. And yet, are baseball executives who are armed merely with radar guns, laptop computers, and “hunches” about their players entitled to call themselves “Moneyball” practitioners? I think not.

They do merit that distinction, however, if they collect multiple data points on individual players in myriad game situations, mix data and crunch it in countless ways, and filter it through their own lens of practical experience – all in the service of producing pre-agreed-upon, highly measurable outcomes.

In baseball, the intended outcome of “Moneyball” typically is wins. In precision agriculture, it’s typically yield or crop quality, and often both.

So I ask again: Are you a precision grower? If you’re not, are you ready to become one? You may be closer than you think.

(Source – http://www.cottongrower.com/crop-inputs/precision-technology/are-you-a-precision-grower/)

Read more

Tiling and no-till: A winning combination

The key, he found, is tile drainage.

Overboe grows corn, soybeans and wheat on very flat land, some of which has very heavy clay subsoils. His farm lies on the bottom of the ancient Lake Agassiz. The clay layer below the 1-2 feet of topsoil is so dense that the water doesn’t drain down any further. That’s an advantage when it’s dry, but a problem when it’s too wet.

In other parts of the U.S., deep ripping or subsoiling might improve the situation. Dave Franzen, North Dakota State University Extension soil specialist, says deep ripping in the Red River Valley doesn’t work becayse the clay subsoils are 50-100 feet deep. “There’s no way to punch a hole through it,” he says.

However, properly installed drain tile can move excess moisture out of the soil.

Over the past five years, Overboe has had all of his fields pattern tiled. Four-inch diameter tile lines were installed 24- to 36-inches deep. The lines were spaced 40-feet apart, except in very light soil where they were spaced 100- feet apart. Water collects at the end of the fields and is pumped into county and state highway ditches.

“Now, I can leave residue on the soil surface and not have to worry about the field being too wet in the spring,” he says.

After installing tile, Overboe saw the most dramatic change in a 355-acres tract along the Sheyenne River. He couldn’t plant the field in 2015 because it was too wet. He ended up enrolling it in the Prevent Plant program. After the field dried out over the summer, Overboe was able to tile it. In 2016, he no-till planted corn in it in late April, even as many of the surrounding fields were being tilled to dry them out.

An electric substation sits in the middle of the field. The tile doesn’t run below the substation. When Overboe was planting corn, the power company was doing some work at the substation and had 4-wheel-drive vehicles slogging through the mud on the substantion property to get to the equipment.

“I was able to plant right up to and around the substation without a problem,” he says. “Without the tile, I wouldn’t have been able to get through there. The field probably would have been Prevent Plant again.”

No-till tricks
Overboe does a couple other things to make tile and no-till work well together:

 He leaves corn and wheat stubble standing. Overboe uses a stripper header to combine wheat, and he doesn’t use a stalk chopper on corn. Given the angle of the sun in late April and early May, more sunlight is able to reach the ground and help dry it out and warm it up when the stubble is standing rather than laying on the ground like a mat.


TALL STUBBLE: Lynn measures the 18-24-inches of wheat stubble that was left standing by the stripper header.

 He controls field traffic. After installing tile, Overboe didn’t work the whole field. Instead, he made a 12-foot wide toolbar and mounted two loader blades on it to pull the berms back over the trench. He also asked tile installers to leave their loaded trucks on the roads so they wouldn’t rut up the fields. “I don’t want to work the whole field after installing tile, because tillage destroys the soil structure and reduces the earthworm population that I’ve built up with no-till,” he says.

Earthworms are an indicator of soil health, he says. They eat residue, produce organic matter and create tunnels for water to flow through.

“That’s the whole point of no-till — to improve the structure and the biological life in the soil,” says Overboe. “Tile drainage helps me do that.”

(Source – http://www.dakotafarmer.com/crops/tiling-and-no-till-winning-combination)

Read more

Cover Crop Acreage Brings Big Benefits

A recent survey revealed that thousands of farmers are planting cover crops and reporting benefits from the practice.
While only a few respondents to the fifth annual cover crop survey were from Mississippi, the study revealed more landowners appreciate the practice of growing crops to protect and enrich the soil. Most respondents were from the Midwest in the survey conducted by the Sustainable Agriculture Research and Education program and the Conservation Technology Information Center.
Cover crops are sown between growing seasons and usually not harvested for profit. In some areas of Mississippi, cost-share programs are available for cover crops under the U.S. Department of Agriculture Natural Resources Conservation Service’s practice code 340.
Large agricultural producers and small gardeners alike know that soil health is just as important to success as water and sunshine.
Soil health is a key benefit from planting a cover crop, such as this cereal rye on a northeast Mississippi farm.
Of 2,012 survey respondents, 88 percent reported using cover crops, with years of experience ranging from just one year to more than 10. When the first survey was conducted in 2012, farmers reported planting an average of 217 acres of cover crops. That number steadily rose to an average of 400 acres in 2016, and it is projected to reach 451 acres in 2017.
Paralleling a continued emphasis on sustainable soil management, 86 percent of respondents noted soil health as a key benefit of planting cover crops. Fifty-four percent reported that soil health benefits began in the first year of use.
Despite the benefits and growing popularity of integrating cover crops into production systems, maximizing the benefits of the practice takes time, careful planning and research. If not implemented properly, cover crops can most certainly create pitfalls. Here are three tips for getting the most out of a cover crop.
First, identify your goals for the upcoming season and select the appropriate cover crop or mix of cover crops. Some reliable choices for the Southeast include cereal rye, oats, wheat, radish, winter pea and vetch.
Second, proper timing is one of the most important aspects of planting success. By this time of year, it may be best to just start researching for 2018. Optimal planting time for many cover crops is relative to the potential for frost. In Mississippi, the average first frost dates range from Oct. 26 to Nov. 5. Sow seeds about 30 days before the first anticipated fall frost date in your part of the state.
Third, choose a cover crop that is easy to kill when you need to prepare for the upcoming cash crop planting season. The timing, effort and method of termination are also crop-dependent.
Many local, independent businesses carry seed for cover crops, often available by the pound — a plus for small gardens. Co-ops and garden centers can order seed, as well.
(Source – http://www.farms.com/news/cover-crop-acreage-brings-big-benefits-129107.aspx)
Read more

Genetic discovery another tool in battle against wheat pests

Greenbug and Hessian fly infestations can significantly reduce wheat yield and quality in Texas and worldwide. Breeding for resistance to these two pests using marker-assisted selection just got a new tool from a Texas A&M AgriLife Research study.

Because genetics is the most economical strategy to minimize losses, AgriLife Research wheat geneticist Dr. Shuyu Liu began two years ago searching for breeder-friendly markers for those two insects. This step is a continuation of ongoing genetic work on insect resistance.

Through the years, a number of greenbug resistance genes have been identified in wheat and its relatives based on their differential reactions to different biotypes, which range from A through K. There are also 18 Hessian fly biotypes, and because it has the ability to overcome resistance genes deployed in wheat cultivars through mutations, it is necessary to identify and utilize resistance genes from diverse sources for wheat breeding.

Scientists use genetic markers to identify regions where specific genes can be found on a particular plant. Liu has identified the neighborhoods or markers for a gene offering greenbug resistance, Gb7, and a gene that provides Hessian fly resistance, H32, in wheat.

Liu’s work was recently published in the Theoretical and Applied Genetics Journal of Plant Breeding Research, detailing the development of the Kompetitive Allele Specific Polymerase Chain Reaction or KASP assays for both genes.

Joining Liu on the publication were AgriLife Research wheat team members Drs. Jackie Rudd, Amarillo, and Amir Ibrahim, College Station, both wheat breeders; Dr. Qingwu Xue, crop stress physiologist; Dr. Chor Tee Tan, an associate research scientist; as well as other students and staff in Amarillo.

This project was funded by AgriLife Research and the Texas Wheat Producers Board.

Both genes were identified through previous research, and linked markers for them were mapped, but the detection methods were not well suited for marker-assisted selection for evaluating thousands of plants, Liu said.

He said knowing an address doesn’t mean someone knows where in the city to start looking for it. But by developing single nucleotide polymorphism, or SNPs, which include flanking markers closely linked and located on chromosomes, geneticists are able to give breeders the neighborhood to search.

SNPs are then converted into KASP assays, which are considered breeder-friendly because they are easier to use, faster and more accurate, he said.

Effective molecular markers closely linked to the target genes are the key for the success of marker-assisted selection on traits such as greenbug and Hessian fly resistance, Liu said. For instance, a breeder will typically screen 1,000s of breeding lines, and the KASP acts as a flag to say the necessary genes for a particular trait exists in a particular line.

Through Liu’s work, both genes can now be easily transferred into a new wheat line through marker-assisted selection.

Liu said the Gb7 and H32 are both found in a synthetic wheat, W7984, which is a parental line for a mapping population that wheat researchers are using worldwide. Synthetic wheats are man-made crosses between Durum or pasta-type wheats and Aegilops tauschii. These initial crosses provide access to genes of the wild relatives of wheat, thus increasing usable genetic diversity for breeders to improve winter wheat varieties.

The mapping population was developed more than 10 years ago by the International Triticum Mapping Initiative, but neither of these genes has been used for resistance in breeding programs to this point, he said.

“The reason I think they were not being used is they were in a synthetic line and it required more effort to transfer them into adaptive wheat lines,” he said. “What we have done with the KASP marker is make them easier to find and utilize.”

For example, TAM 114, a newer, increasingly popular variety of Texas A&M wheat, does not have greenbug resistance and only has limited Hessian fly resistance, Liu said.

“But with this new knowledge, breeders can cross with TAM 114 and keep its superior end-use quality and improve it with the Gb7 and H32 genes,” he said. “This will make the new line more adaptable to the regions where Hessian fly is a problem.”

By crossing wheat lines with the identified KASP markers, the process to develop the pure line with selected properties can be much more accurate, Liu said.

Liu said he began searching for these markers because the TAM breeding program has made heavy use of synthetic germplasm so the markers will quickly be implemented.

To get to this point, Liu utilized genotype-by-sequencing markers developed by other research groups, and ultimately the KASP markers were validated using the set of synthetic wheat lines. Each line of that mapping population was screened for reactions by greenbug and Hessian fly by two U.S. Department of Agriculture Agricultural Research Service centers.

“We’ve determined they are very effective under many genetic backgrounds,” he said. “Genetic diversity and genetic gains are always important to wheat breeders.”

(Source – https://www.eurekalert.org/pub_releases/2017-11/taac-gda110817.php)

Read more

Easing the Soil’s Temperature

Soil characteristics like organic matter content and moisture play a vital role in helping plants flourish. It turns out that soil temperature is just as important. Every plant needs a certain soil temperature to thrive. If the temperature changes too quickly, plants won’t do well. Their seeds won’t germinate or their roots will die.Miscanthus roots break up the soil.

The roots of miscanthus break up the soil, keeping it from becoming compacted. Photo credit Timothy Reinbott.

“Most plants are sensitive to extreme changes in soil temperature,” said Samuel Haruna, a researcher at Middle Tennessee State University. “You don’t want it to change too quickly because the plants can’t cope with it.”

Many factors influence the ability of soil to buffer against temperature changes. For example, when soil is compacted the soil temperature can change quickly. That’s because soil particles transfer temperatures much faster when they are squished together. When farmers drag heavy machinery over the soil, the soil particles compact.  Soil temperature is also affected by moisture: more moisture keeps soils from heating too quickly.

Research has shown that both cover crops and perennial biofuel crops can relieve soil compaction. Cover crops are generally planted between cash crops such as corn and soybeans to protect the bare soil. They shade the soil and help reduce soil water evaporation. Their roots also add organic matter to the soil and prevent soil erosion. This also keeps the soil spongy, helping it retain water.

But Haruna wanted to know if perennial biofuel and cover crops could also help soils protect themselves from fluctuating temperatures.  Haruna and a team of researchers grew several types of cover and perennial biofuel crops in the field. Afterwards, they tested the soils in the lab for their ability to regulate temperature.

Taking soil samples in field

Soil scientist Samuel Haruna samples the soil in order to determine how cover and perennial biofuel crops affect soil temperature. Photo credit Samuel Haruna.

“I was amazed at the results,” Haruna said. He found both perennial biofuel and cover crops help soils shield against extreme temperatures. They do this by slowing down how quickly temperatures spread through the soil. Their roots break up the soil, preventing soil molecules from clumping together and heating or cooling quickly.  The roots of both crops also add organic matter to the soil, which helps regulate temperature.Additionally, perennial biofuel and cover crops help the soil retain moisture. “Water generally has a high ability to buffer against temperature changes,” said Haruna. “So if soil has a high water content it has a greater ability to protect the soil.”

Although Haruna advocates for more use of cover crops, he said it’s not always easy to incorporate them into farms. “These crops require more work, more financial investment, and more knowledge,” he said. “But they can do much for soil health.” Including, as Haruna’s research shows, shielding plants from extreme temperature changes.

“Climate change can cause temperature fluctuations, and if not curtailed, may affect crop productivity in the future,” he said. “And we need to buffer against these extreme changes within the soil.”

Haruna hopes to take his research from the lab and into the field. He says a field experiment will help him and his team collect more data and flesh out his findings.

(Source -http://www.farms.com/news/easing-the-soil-s-temperature-128931.aspx)

 

Read more