By Bob Streit, Crop Consultant, Boone, IA
Welcome to the summer of 2015! There were several hesitations and reversals but it seems that summer has finally arrived. Luckily the cold and freezing temps stayed far enough north to not put our crops at risk. After seeing many acres of small corn plants that formed grayish leaves from their brush with frost just two weeks ago, we need clear sailing for several months to maximize yields. Then we have to see what part of the country does not luck out so as to now have burdensome supplies of grain.
What is planned for this summer’s weather is still a puzzle. The El Nino signal is a strong negative, yet there are a few lows that seem to have gotten established hundreds of miles away from normal. What will happen? Texas and several other states have been getting drowned out with very heavy rains, which has been a sharp contrast after their four year long drought which decimated their cattle herds. Who would have thunk it?
The Corn Crop
There is corn planted in early mid April that is now in the V6 growth stage, and there is corn that has just emerged. The recent ten day period where very few heat units were captured served to delay the later planted corn even more and whether it reaches knee high by July 4th is in question. My advice to the farmers in April was to get started as early as possible even if the forecasts were for cool conditions and if the ground worked decently, because the way the crop has died four to six weeks early the last six years meant that the first planted corn was going to have completed a higher percentage of its fill days before it ghosted out. One piece of advice given was to plant the heavier bags of seed if possible since the heavier kernels tend to have more energy available to nurse the small seedling along if they needed that support.
In general the stands seem quite good though there are occasional fields where a percent of the plants either never emerged or the plants were runts coming out of the ground, days behind their counterparts.
Two weeks ago it was surprising how clean so many of the corn fields were and how well the residual herbicides were working. Now that observation has changed in many fields, growers are wondering where all of the broadleaf weeds have come from.
The small pigweeds are getting some size and are easier to see. There must have been lots of plants that went to seed around or thru the waterholes during the recent wet springs and seasons. The giant ragweeds are growing enough to know why they are called giant. And where did all the cockleburs come from? Who or what could have carried them into fields that never had a problem before? Now the urgency is there to eliminate or manage them while they can be controlled and any herbicides are capable to working as planned.
It also appears to be a good season for Canadian thistles. There are many fields where all the patches are growing very well and are noticeable from a long distance. Those are tough competitors and need special attention since they are tough to control whenever soybeans are planted in the field.
Many corn growers seem to have noticed that quite a few fields are now looking ‘ugly’. The dark green sheen that many fields had 10 to 14 days ago has given way to a yellowing tint or a very mottled yellowish appearance. It is these fields where tissue tests should be taken and sent in for a tissue or sap analysis to determine which micronutrients are below the critical level of health.
After a few seasons of correlating test results with live appearance, one can easily see a new field and be accurate in guessing what nutrient shortages will be diagnosed by the testing lab. That light-green/dark green appearance is not normal and just ignoring it is like ignoring a toothache. The damage or result can get very costly in the end. Applying the proper mix of micronutrients using the right water pH and with the right additives, as documented by such testing as needed, could likely be the highest ROI trip you could make this summer. This yellowing can be indicating that Fusarium infections are beginning to invade your corn plants’ roots. This loses yield and can lead to early plant death. We like using AgriGuardian’s MicroMix for this application.
One tip that a farm operating advisory company used to push based on a research finding at Purdue was that by making a V4 foliar trip applying a high grade P fertilizer could add 2 to 4 kernel rows to the ears. That window closes after the V4 stage, yet maintaining a high P level helps the plant develop as quickly as possible and reach the established yield goals. Meeting the fertility needs also goes a long ways in maintaining good plant health during the season and avoiding problems with leaf diseases.
The Soybean Crop
The majority of the bean fields are between emerging and perhaps reaching the early V1 growth stage, which is forming the first set of trifoliate leaves. Most growers listed to advice and at least applied the minimum amount of seed treatments, which included Apron and Maxim, thus little to no replant has been required. Bean growers aiming for profitable yields need to recognize that a three or four product mix applied at the V3 to V4 growth stage is likely the added application that can boost yields by 8 to 12 bu/A on a regular basis.
The products to use and minerals mix to include was something gleaned by knowing some good fertility researchers and getting to spend a few days with the top people out of Brazil last summer after the Farm Progress Show when they wanted to walk a few fields while it was raining. Never turn those chances down. We now know the key to growing the deep, expansive and health root systems that used to be the norm.
Raising high yield beans, like Ray Rawson or Kip Cullers, or Bill, Keith, or Dan, is more a game of chess than checkers. You always need to be planning and anticipating your next move that might be two or three weeks into the future. If someone tells you an idea is stupid, ask them why they might think that, then look for shortfalls in their approach or strategy. Remember that according to physics rules, bumble bees cannot fly. Did they not pay attention to batch pH, or tissue test results, or the need to foliar Ca due to lack of knowledge? Should they have understood and addressed leaf biology since it is important?
In both 2010 and 2014 when SDS became a major problem the observant crops people were noticing fields where the bean plants began to turn a yellowish color. This ended up being the clue that the root phase of the disease had begun. Time wise this would have been during the first two weeks of June.
Other related factors were saturated and often compacted soils, known high levels of Fusarium fungi soil affecting previous crops, having planted susceptible germplasm, and a decreased immune response via poor Mn, Cu, Zn, and Co levels. This is not the year to lose bushels to a disease that could have been prevented with preventative and good crop management. It does require planning and being able to recognize the challenges that nature will present.
Here’s wishing you’re the best of luck in the next weeks while you can positively influence crop yields.