Renewable Farming

Crop consultant Bob Streit: Planning for “longer survival” for corn in 2016

April is here and there were few surprises with its arrival. So far the weather in March was warmer than the low 50s during the day and night time temps still dropping below freezing. Most mornings last week there was ice on the water in most buckets and in the waterholes. Though that is not a rarity, it is not allowing the soils to warm up and for corn growers to get anxious about not having any corn in the ground. There are many fields of oats and alfalfa that have been seeded as a gentle rain is always nice to get the seeding off to a good start.

With the insurance date for replant coverage only a week away, we will likely see little field activity except for N fertilizer being applied and a few of the soybean premerge herbicides getting sprayed on. The weather in Arkansas and Louisiana was record wet a few weeks ago.


Meteorologist Elwynn Taylor has long observed that their wet weather trends tend to move north three to four weeks later. If that is the case, there could be weather delays ahead. Let’s hope they are not major, but with the profiles being full in nearly every locale it will not take much additional moisture to slow field traffic.

Those same conditions could mean that any efforts or products, be they nutrient or biological in nature, applied to the seed or in-furrow could pay dividends in promoting better early growth or better seedling health.


Changes in N Practices

One big change this season has been the pricing of urea fertilizer. In years past it has typically been $.10 to $.15 per pound more expensive than 82%. Apparently the supply ratios have changed and this year. Most retailers have those two forms of N priced the same. A number of growers are asking if this is a good thing, and if there any advantage or timing differences between the two forms. Expect taller tired, dry box rigs running thru the fields applying 46% to crops that might be up to the V8 growth stage and substituting for a sidedress rig with cheaper priced material.

Down in the southern and southeastern states a high % of the N goes on in the dry form as top spread material. For years they ran the risk of having a major portion of the N denitrify into the air if they did not get rain during the first week. Today many of those fears have been removed by what the fertilizer handlers have done. There are several stabilizers that work well in minimizing or eliminating leaching or denitrification. A number of major firms are also using poly coating on the small granules so they become a slow release form of N.

One fear of corn growers is that if they rely on surface applied material the N may end up sitting near the surface in a dry season and being unavailable to the plants. There are some growers who have built rigs whereby they can dribble on granules next to the base of the plants where the dews of the early and mid summer months will carry it into the root zone.

In studies done at Purdue it was established that corn plants did prefer to pull in nitrogen in the ammonia form. Less energy was expended utilizing 46% versus 28% or 32%. Late season ammonia can help form heavier grain with higher protein content. This past year we saw a bit of late season cannibalization in the upper leaves. This was a portion of the late season plant decline, but now helps explain the entire corn crop dying 4 to 6 weeks early in each of the last 7 years.  


Planting Depth

Ten years ago there were still two different arguments to how deep to plant corn kernels. There were people suggesting shallow planted kernels emerged quicker and began to grow faster. Then there were opposing parties that claimed the deeper planted kernels ended up forming more roots. Those extra roots served to better anchor the plants and served to pull in more water and nutrition from the soil. Enough replicated trials and observations were made to show that the deeper kernels formed more rings of roots and a greater number of roots which tended to be a big advantage in end performance.

There is not an issue with soybean seeds, as we have all seen soybean seed laid very shallow and still produce a healthy plant. One of the more important items on producing top yielding soybeans is to do what it takes to form as many branches as possible. That is why most of the contest winning bean growers follow advice that helps them grow their bean plants to twelve inches in height as quickly as possible, with as many roots and branches as possible, but then switch gears to stunt their upward growth and spend energy forming and filling the pods versus growing foliage.


Weed Control

By now most growers have settled on which residual herbicides they will be applying. It is rare to find a person who still relies solely on two application of the systemic herbicide and expects to control their problem weeds. There are going to be a few different additives that can increase penetration of the sprays and deliver more of the product to the plant’s vascular system. That tactic could apply if lack of dosage was the problem. Weed scientist have verified that many tolerant weeds make multiple copies of the genes that over-ride the sequence that offers susceptibility to that class of chemistry. In time repetitive exposure to the less effective herbicide family breeds more resistant progeny weeds.

In one story on Palmer amaranth, the quoted experts noted they were seeing that a portion of the Palmer weeds were initiating seed heads within twelve days of emerging. Since the plant’s physiology changes when the reproductive stage begins, we may see the growth-regulating herbicides become a lot less effective than had been expected. Time will tell. At this time a few retailers are suggesting that growers plant traited varieties that are not fully approved for the market. Is that a wise thing?


Plant Health

After a winter to think about it, there are more growers calling and asking about why the corn in most of their locales began to die by mid August the past several seasons, and was often completely dead by August 20th.

So far it seems to be a real hot potato question the experts either can’t answer or don’t want to answer for fear of stepping on toes. They recognize that the current emphasis on soil and plant health is telling them it is important, but there are very few constructive guidelines to follow other than plant cover crops, which are good. But then what is the common means of terminating them? You can’t have it both ways.

With the beginning of the planting season only being two to three weeks away, what constructive steps do you plan to use to keep your crops healthy and able to deliver on the expected last three to four weeks of grain fill?

Learn more about what a healthy plant should look like and what mineral deficiencies are going to look like. Learn about micronutrients if you don’t have fields that have received lots of nutrient rich manure the last decade. Then ask the right people about the product called BioEmpruv, because the supply is limited and the proverbial early bird will get the worm again. It is nice to have the only green and healthy corn in the neighborhood and then notice you are pulling the most loads of grain out of the fields in mid October and the plants are still standing.

By Bob Streit, Boone, Iowa April 5, 2016     515-709-0143