Del Voight – Penn State Extension
HEre is a link to the 2018 Bt trait table. This is handy in case one is out and identifies a pest issue to double check the traits purchased either does or does not manage the pest.
https://lubbock.tamu.edu/files/2018/01/BtTraitTableJan2018.pdf
Del Voight – Penn State Extension
Coming into work this morning I saw a grower heading out to apply spring burn down on one of their fields. I no sooner got into the office and I received a call on spray or not to spray. The dialogue is whether to go ahead and spray today temp 45 night time 30. The growers want to apply glyphosate and 2,4-D and not switch to glufosinate or paraquat. SO focusing on the glyphosate and 2,4-D. Bottom line the rye and other weeds have to be actively growing for the products to work. They can be applied and decent control might result but one might find themselves treating again for missed spots in the field. Here are some rules of thumb, if night time temperatures are 50 or above 2 days before and 2 days after application the application should work just fine but expect a slow process. However if night time temps are 32 or below 2 days before or 2 days after application then poor results will likely result( WITH THESE PRODUCTS). In this case doubling the rate would be beneficial to ensure the concentration of salt int the plant stays high so it gets absorbed when growth returns.
In Illinois, back in 2003 research was funded by the Illinois Soybean Program Operating Board to look at systemic (glyphosate and paraquat)–Christy Sprague and Aaron Hager . There were three herbicide treatments, glyphosate (Roundup UltraMax), paraquat (Gramoxone Max), and paraquat (Gramoxone Max) plus metribuzin (Sencor), were applied at six different application timings based on daytime high air temperatures ranging from 47° to 87°F. The herbicides included one herbicide that was systemic in nature (glyphosate), one that was contact in nature (paraquat), and a contact herbicide combined with a herbicide that had soil residual activity (paraquat + metribuzin). Weeds evaluated included common chickweed and henbit. Overall what they found was that increases in temperature significantly enhanced weed control and reduced weed biomass. The treatment least affected by temperature was paraquat plus metribuzin. This may be attributed to the soil residual activity of metribuzin. Some weed control provided by this treatment at lower temperatures may have come from this residual activity. Differences also appear to exist in how application temperature affects control of these two species. Temperature had little affect on common chickweed control with glyphosate; however, application temperature significantly affected glyphosate activity on henbit. When deciding whether it is too cold to spray, make sure to consider what weeds are out there and what type of herbicide you will be using. Armed with some information I would advise not to be spraying today wait until warmer temperatures come back or consider another herbicide choice.
Del Voight – Penn State Extension
Take Home:
The Process
The seed sprouts lateral and hair roots develop and send a signal that matches needs of the B Japonicum inoculant and the roots open a pathway for the bacteria to invade and nodules form. Properly functioning nodules will be be pink in color because Leghemoglobin is red, the inside of an active nodule is pink. Sugars produced in the leaves move down the stem and into the nodules as an energy source for the bacteria so they can fix nitrogen. Stresses such as cold, drought, flooding, and low soil pH interfere with the establishment of the nodules and the with the nitrogen fixation process.
Why Inoculate?
One bushel of soybeans requires 3.5lbs of N for a 100 bu crop that would be 350lbs of N per acre. The nodules fix and supply this demand from the Soils if handled properly. Soils do not contain the rhizobium bacteria specific to soybeans called Bradyrhizobia japonicum . The soybean root will send signals out to nearby B Japonicum to trigger and genetic link between the two and begin to form a relationship where the plant feeds the bacteria and the bacteria in turn turns atmospheric N into usable N for the soybean plant to use for growth. This picture by (G. Roth 2014)illustrates the dramatic affect it has on soybeans if this process of inoculation does not occur. Soybeans on the right with N deficiency.
The nodules are typically formed on the main stem and the fine root hairs from emergence to V2 but the process continues but the main infection occurs early and growers can scout at V2- R1 to count for nodules that should be present. If not perhaps additional N might be responsive. A properly nodulated soybean plant should have five to seven nodules on the tap root two weeks after emergence or twelve total root nodules per inch of tap root at flowering (R1)(R. Elmore 2007). Typically on high yielding fields I have focused on the main stem and get about 10 large nodules on the main stem at R1. To evaluate nodule performance, cut
nodules in half. Nodules that are actively fixing nitrogen will
be colored pink to bright red, while nodules that are white or
green are not producing or have not begun to fix N.
To get the rhizobium B japonicum in the soil growers need to provide this. Manufacturers of the B japonicum have refined the process and improved delivery and even the sub species with better more efficient B japonicum. The modern sterile products are four times more productive than the older non-sterile materials. (Also more profitable)( Ohio State Extension 2009) There are advantages to inoculants and there are numerous configurations of ingredients that can be applied to seeds.
Newer products may contain improvements:
1) Plant growth promoting hormones.
2) Disease control materials and other bacterial Bacillus etc.
3)Signals to induce / speed nodulation in cold soil.
4) Extenders to protect the bacteria, allowing inoculation up to 30 days before planting.
5)Binders to improve adherence to the seed.
6)Nourishment for the bacteria.
Ideal Environment for inoculations
It is important to understand the environment for which will best suite this relationship of the root and the B japonicum. Elevated Aluminum in the soil can be alleviated with maintaining the soil factors as below.
–pH- 6.5-6.8 Ph of soil should be maintained and 6.5 preferrably 7.0 and if questionable sampling or testing or below 6.5 the addition of Molybdenum at .25lb of sodium molybdate per acre will aid in infection. The Pa On Farm Network over three years tested Moly on fields with pH lower than 6.5 and found a significant response to moly applied either on the seed and or in the V 1 stage. Here is one years results. A 2.5 bu/acre response over 3 years and 38 replications on both farm and research station work.
–Optimum P and K
–Moist but not wet
–Ideal 77 degree F for most species of B Japonicum but advances may be coming to aid with cooler soils.
–Rapid germination and colonization by rhizobium will take place if the soil and root systems are conducive to infection. This may not line up with extremely early planting as many times soils are much colder than normal.
First Year syndrome
Virgin Soils (soils without soybeans in rotation for 5 or more contiguous years) require special treatment and a willingness to live with lower yields the first season.
Tactics:
Caring for inoculant is important!
It is true that millions of bacteria are supplied within the bag of purchase inoculant however those bacteria can die quickly with major swings in temperature and direct sunlight so here are some tips.The majority of the B Japonicum cells survive best at 40 to 80 F. and should be stored in a cool place out of direct sunlight. The shelf life of inoculation materials is from a few months to two years depending on formulation and additives in the product. Follow these storage parameters to maintain viability.
Causes of failures
What about annual Inoculation?
Answer these questions for your specific field: This list provides some insight into where annual inoculation is most beneficial and is a work in progress. Any points means better to inoculate.
GIP (Good Inoculant Practices) for applying Inoculants
Before applying an inoculation material it is important to check its compatibility with any other seed delivered technologies.
When non-compatible materials are on the seed, plant within four hours of inoculant application if possible. Compatible fungicides are: Apron, Allegiance, Maxium, and biological materials. All new materials use a sterile media and have up to 108 bacterial cells per gram of inoculation material. Use application rates provide over 800,000 cells per seed. Most products have an adherent and anti-desiccant to protect bacteria cells. All have nutrients to maintain cell viability and activity. Over application is not toxic to the seed, but is expensive and may cause metering problems for the drill or planter. Seed can be inoculated when loading a drill with an auger or when loading by hand or from bags.
What is the best method to get inoculant applied?
Liquid and dry materials perform equally well when used properly. However, Liquid materials have a longer shelf life and are easier to use. Some newer materials can maintain viability on untreated seed for sixty days or more, and for seven or more days when applied over some fungicides. This is important as even if commercial applied if fungicides are utilized at the same time that may affected inoculation then direct planting is advised.
Many growers are using a 15 inch row planter with pop up liquid applications and using water 3 gal/acre as a carrier to direct apply liquid inoculants on the seed in the field at the same time which is the most preferred method of inoculation.