Choosing The Right SCN Soybean Varieties
Soybean growers should take care when selecting soybean cyst nematode-resistant varieties because they aren’t all created equal, says Mike Staton.
Look for yield data taken from SCN-infested fields or plots, select several varieties and evaluate their performance on your farm, the Michigan State crop and soil scientist says. Also look at the ability of the resistant varieties to inhibit SCN reproduction in infested fields.
Farmers are also advised to collect soil samples at planting and harvest, because with effective SCN-resistant varieties, the numbers of nematodes recovered from the harvest sample should be lower than the one collected in the spring.
Fungal Signaling Discovery Could Bring New Fungicides
Researchers at the University of Exeter in England have discovered how pathogenic fungi avoid immune responses of the plants they attack.
Scientists found that signaling organelles in the fungus travel rapidly between the plant-invading fungal cell tip and the fungal cell nucleus, enabling the fungus to produce proteins that it injects into the host plant cells so that it can enter the plant immune system unrecognized.
The researchers say the mechanism occurs early in the fungal-infection process, when fungi are most accessible to fungicide treatment. Disabling the process could result in a new generation of fungicides that are able to act before the plant is harmed.
Gypsum Application Could Clean Up Farm Runoff
Gypsum applications could have a beneficial quality in reducing phosphorus runoff from farm fields, says Warren Dick.
The Ohio State University soil scientist says farm fields treated with gypsum in an ongoing study are seeing an average 55% reduction in soluble phosphorus runoff, based on tests of water samples collected from the fields’ drainage tiles. Gypsum’s effects on soil quality and crop yields are also being studied.
Soluble phosphorus runoff from farms is one of the causes of harmful algal blooms plaguing Lake Erie and other lakes in recent years.
Organic Corn Returns Exceed Those From Conventional
In 2010, U.S. producers saw average returns of $307 per acre for conventional corn, compared with $557 per acre for organic corn, primarily because higher organic corn prices more than offset lower organic corn yields, says Linda Foreman.
The USDA ag economist says total operating and ownership costs per acre weren’t significantly different between organic and conventional corn. Three major components of operating costs — seed, fertilizer, and chemicals — are lower for organic corn than for conventional corn, while some ownership costs — the capital recovery of machinery and equipment, and taxes and insurance — are higher for organic corn.
Although acres planted to organic corn nearly tripled between 2001 and 2010, organic corn accounted for less than 1% of total 2010 corn acres.
Resistant Weeds Not Controlled By Fall Residuals
One misconception regarding fall herbicide applications is that they will work well into the spring to help control initial flushes of glyphosate-resistant weeds, such as Palmer amaranth or horseweed.
“This is simply not true,” says Tom Barber, weed scientist for the University of Arkansas. Residual activity of herbicides applied in the fall begins to decrease rapidly in early March in some states, when soil temperatures begin to increase. Extended cool, wet springs the last two years gave way to increased temperatures that caused one of the worst problems with glyphosate-resistant horseweed he’s seen.
In most situations, seeding a cover crop like wheat or cereal rye that is easy to kill, and an early spring burndown herbicide application, can reduce populations of winter annual weeds, Barber says.
Right Place, Right Time For Wheat Nutrients
A successful fertility program for winter wheat should consider the mobility and uptake requirements of nitrogen, phosphorus and potassium, says the International Plant Nutrition Institute.
Wheat needs 2 to 2½ pounds of nitrogen per bushel of grain or, if grazed, 1 pound per acre for each 3 pounds per acre animal gain. Adequate nitrogen must be available to the wheat plant at all phases of development.
Winter wheat takes up about 0.6 to 0.7 pounds of phosphorus per bushel of grain produced. Banded or starter applications are often effective in soils testing low to medium. Banded phosphorus also helps young plants overcome the adverse effects of soil acidity.
Potassium is mostly associated with the water economy within the plant and decreased incidence of disease and lodging. Wheat uptake requirement for potash is equal to that of nitrogen. Split applications may be beneficial on low-potassium, deep, sandy soils in higher rainfall areas.
Nutrient Balance Crucial To Corn Yields
A study by Purdue and Kansas State universities found that feeding corn the right balance of nitrogen, phosphorus and potassium is critical for increasing yields.
Data from more than 150 studies showed that high yields were linked to production systems where corn took up key nutrients at specific ratios — 5-to-1 for nitrogen and phosphorus, and 1-to-1 for nitrogen and potassium — regardless of the region where the corn was grown. Purdue agronomist Tony Vyn says growers need to be as concerned about the amount of potassium available to their plants as they are about nitrogen.
“We need to focus on the nitrogen-potassium balance because that’s where we have the greatest deficiency in terms of application, especially in the eastern Corn Belt,” he says.
Brachiarias Serves As Cover In South America
Brazilian no-tiller R.L. Guerrero finds that the tropical grass Brachiarias offers multiple benefits.
Guerrero, who’s using the brizantha species, likes it because it protects his soil from the sun and heavy rain, and its aggressive root system helps break up the hard, dense volcanic soil. The species also provides the possibility for use as pasture for cattle. A grower he knows found his beef was more profitable on Brachiaria over the winter than on soybeans.
The downfall is that Brachiaria isn’t very cold tolerant, so Guerrero will try Panicum maximum next winter.
Glyphosate-Treated Sorghum Increases Wheat Yields
Glyphosate applications to grain sorghum prior to fall harvest can help improve the performance of the following wheat crop if applied early enough, Kansas State University says.
University field trials found that 2012 wheat following glyphosate-treated grain sorghum that was applied at least 38 days prior to the first freeze yielded an average 6% higher than 2013 wheat that had glyphosate applied to grain sorghum 6 days before the first freeze.
Overall, when glyphosate was applied to sorghum pre-harvest, wheat yielded 6% to 7% more than wheat following untreated sorghum.