Midwest crop consultant Bob Streit's July 8 field report

Here are Bob Streit's latest field observations, which will be posted later this week on his website, Central Iowa Agronomics. We wanted  you to have his review quickly as possible since the next four days may offer some clear weather to cope with the consequences of excess rain in soybeans and corn.

July 8, 2018   By Bob Streit — After a week that was interrupted by the fourth of July holiday and rain again in the Northwest part of the state growers in the state get another chance to try to get things back to normal. Seven days ago we woke up after the Des Moines area received 5 to 10 inches of rain. Everyone in that area or downstream got the chance to see how much damage occurred during and after that storm. Then to top that off a large area in west central and southwest Minnesota was deluged with 6 to 12” on Tuesday. Fields, crops, buildings and roads were all damaged or destroyed. The same system dropped heavy rains on eastern and central Nebraska and they now have the same large ponds on their ground where the beans and corn plants have yellowed and collapsed. In summary it is much easier to farm when conditions are on the dry side. When Dr Atkins predicted an atmospheric river setting up over the midsection of the country I didn’t think it could last so long. Still those large counter clockwise rotating storms stretching from northern MN down to Mexico crossing the country at this time of year is unusual. 

Meanwhile when grain prices typically hit their highs when harvestable crop acre numbers are on the decline our commodity prices are also going down. The July 6thdeadline for imposition of some of the tariffs arrived and the commercial traders responded to the expectations by taking the prices lower. Everyone in Ag was hoping the threats would just be a bargaining chip.

Hopefully everyone got to enjoy at least part of the Fourth taking a small break, and maybe enjoying the fifteen minutes of fireworks. We still live in a free country where patriots had to pay with their personal sacrifices and some their lives, hopefully to escape the wraps of a tyrannical government. Let’s hope we can keep it that way for a long period again.

Field Happenings

The battle to manage nitrogen has continued thru this date and was a good battle with people using tractor pulled side dress rigs, top dressed urea, Y drops with self propelled sprayers and finally aerially applied urea. It was a good battle and there are many fields that look good, either because those tactics worked, the ground had the slope or drainage system to get rid of the water, or the stabilizers worked, but it is becoming more apparent that there are quite a few fields that are now showing lots of yellowing. This is likely compounded by the fact that nearly all fields we had tissue tested showed very low or non-detectable molybdenum levels. That is the mineral needed by the plant to form the nitrate reductase enzyme which allows the plant to utilize nitrate nitrogen. Very low levels keep the plant from accessing a major share of the nitrogen that is present. Labs that do the tissue testing typically see it being deficient 95% of the time.

We hoped for the best with the corn stalks that had to stand in the ponded water after the first big rains. The water got heated up and the plants died about day #5. Since then the ponds have actually gotten larger since, now leaving us with many black and bare circles in fields. It will be impossible to get to these spots with machinery to replant in order to keep weed seed production to a minimum. The soybeans lasted 3 to 4 days until they died and since then have never dried enough to permit replanting. Most years farmers are able to plant something to keep the weeds down.

One major thought by many growers is that all USDA experts when making their lofty final yield projections figure all these bad acres will produce at least average yields. Regretfully for those farmers that won’t happen.    

Soybeans

The best of the soybean field contain plants which are finally flowering, developing more growth and looking like they may close the 30-inch rows. There are still those where the plants have grown and even reached the V8 to V9 vegetative stage but have not yet begun to flower. It is still a guessing game to figure out what might cause this. We do know that the ammonia nitrogen in any foliar mix triggers flowering. Nitrate nitrogen instead promotes more vegetative growth. The way one learned crop scientist explained it, nitrogen is termed a ‘zwitter ion', in that it can be a positive or negative charged molecule. The term comes from the German word ‘zwishen’ meaning between.

There are still too many acres of yellowed beans, which suggest that the soils are too waterlogged, the roots are likely to be damaged by root rot fungi, or on the path to exploding with SDS browning in August and at risk of dying. Normally most farmers and agronomists would say there is nothing a person could do about this, or might there be a solution? A farmer in N Iowa called us about ten days ago that had one such field planted to a valuable variety, and he ended up having a new product foliar applied. We have the before and after pictures that he took three days apart and we thought ‘Whooahh’. We want to observe it for another week yet before we share the photos and observations.

There was some very good research done by a USDA ARS soil microbiologist who dissected the sudden death issue. What he learned was that a certain non-selective herbicide that is applied to a high % of the bean fields acts as a biocide and kills off the Pseudomonas bacteria, which typically acts as the sheriff in the soil and keeps the Fusarium population in check. When this herbicide, which was granted patent #7771736 as a medicine listing the Pseudo fl as one of the good bacteria it wipes out, the Fusarium population explodes. It is the living entity in the chimera scorch disease. In addition unless an herbicide resistant Trichoderma (as in SabrEx) has been applied to the seed, which normally increase the availability of manganese, which is the mineral which allows the plant to wall off any fungal infection peg, the Fusarium fungus flourishes.   

Farmers who are hoping to increase their bean yields on a regular basis know that between R1 and R3 they have to possess a step by step plan on what extra steps and products they need to do to the plants in their fields. Using the right combination of products at the proper time, with the correct water pH and nozzles are all important items. Then being able to have the fields dry enough to get all these steps implemented is a must. This season has been a difficult one to manage.

So far there have been no major insect problems. I find a few leaf hoppers and an occasional thrip. Expect lots of leaf diseases with the high temps, high humidities, and high number of dew hours.

Corn Observations

Who guessed after much of the corn crop was planted two to four weeks later than normal that we would see a high percentage of the corn showing tassels by late June or early July? This means that the pollination phase should be completed while the moisture supply is excellent to excessive over most of the state.

Several climatologists have been predicting higher temps after July 9 with high nighttime temps, which could negatively affect yields. If that happens it would be a Cornbelt wide issue and most southern locations would be affected. Remember 2011 and 2012 when it was very warm at night.

Tissue test results so far are telling that in general many fields are showing deficiencies in Mn, Cu, Bo, Zn, S and Moly. These are all important minerals for maintaining plant health and deficiencies create a more disease susceptible plant. Since we are having high temps and high humidity the incidence of fungal and bacterial diseases will be high. A close examination of leaves, especially using a hand lens, may show many small lesions already. Those little spots or circles on the leaves are likely to become larger and more serious. Applying a fungicide could slow their development or wipe out the fungal population but will not solve the underlying nutrient deficiency (s).

Farmers who have the better drainage and have fields with 200+ Bu/A potential should preserve that potential plus recognize that the true cause of most corn plants’ death was a bacterial infection that fungicides have no effect on. The disease stays in those fields from year to year overwintering on corn residue. Keeping the plants alive until their natural black layer form, which should be in mid to late September, will maximize yields. We had an irrigated corn grower south SW of Lincoln, Nebraska harvest a field which yielded about 210 in 2016, which was up from 125 in 2010 which was the worst Goss’s year. Using BioEmpruv in 2017 his monitors were consistently running from 310 to 355 Bu/A in that field last fall. He was a happy camper and his yield was proof that controlling the disease can pay in a big way.

Remember that we plan on having the Guthrie Center field days on Aug 20 and one in late September to allow people to see the crops and hear how from different experts how the crop was managed. It is a systems approach and lots of things including soil health and stabilized nutrition play large roles in the success.