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CROP WATCH

By Staff | Jun 5, 2009

With Memorial Day in the rear view mirror we like to evaluate the crops and how they are progressing. At this time last year few western Midwest farmers were done planting corn and many farmers were still waiting to begin planting beans. Constant rains kept delaying progress in getting work done.

This year the planting season started considerably earlier with many growers in northcentral Iowa taking advantage of dry soils and acceptable weather to begin corn planting in mid-April. There were 10 to 12 good days at that time when more farmers joined the parade and got into the fields with their planters.

Since that promising beginning there have been wet weeks when work was delayed, but enough days were good that planting progress in Iowa, Nebraska, Minnesota and the Dakotas is now 98 percent complete. Currently most growers in Iowa and Nebraska have a corn crop that was planted fairly early, where high populations are the norm, and the soil moisture profile is full, and there was no early ponding.

With adequate growing degree unit accumulation yield prospects are excellent for the corn crop. Soybeans are more of a guess yet, but the potential looks good as the majority of the acres were planted by May 25. With aggressive management yields should be good.

All of those positives could be compared to what has happened in Illinois, Indiana and points east. I mentioned two weeks ago that a few of us were in the Springfield area and saw a state that looked about like ours did last year. Through no fault of their own, growers were prevented from getting spring planting done on time.

We traveled back to Iowa on Wednesday and field cultivators and planters seemed to be in every field. Many of the fields likely should have been allowed to dry a few extra days, but like we did last year, most decided to push the envelope a bit and risked causing compaction to get the seed into the ground. In the end nearly 45 percent of their crop was planted in about five days.

Growers switched to early maturity varieties very quickly to avoid high harvest moisture problems, which may limit their yield potentials. So much of their potential will hinge on how many GDUs are contained in the rest of the growing season. High yields won’t be impossible, they will just be improbable.

A few things are occurring at national levels that we need to recognize. Soybean and other grain prices seem to continue to march upwards. The relative strength index is above 80 percent now. The Chinese demand, weakening dollar, and increasing crude oil prices seem to be the major forces behind the increase in prices.

Another item that needs to be watched is a piece of new legislation, House Bill HR 875. It is billed as forcing updating food safety requirements, but seems to have lots of very curious and ominous provisions in it, such as the banning of the planting of any heirloom varieties of select crops, or of any non-GMO varieties. You can Google ‘HR 875’ to read the full text of the bill.

Scouting recommendations

Keep scouting each of your crops and fields. Our arctic-like winter was tough on bean leaf beetle survival, yet I have seen a few fields where plants emerged early enough to attract enough beetles to cause a troublesome amount of feeding.

Considering that 2009 crop soybeans are now worth $10 per bushel, risking problems with PMV doesn’t seem wise.

So on any early-planted beans keep an eye out for the telltale shot holes on the leaves. The beetles can typically only be spotted on warm, calm, days between 1 p.m. and 3 p.m.

Black cutworms are still a minor risk. Typically the potential for an economic infestation is greatest in no-till and reduced tillage fields where winter annual populations were present. Telltale signs of cutting consist of plants that wilt down in the afternoon as the hollowed stalks fall behind on moisture transfer.

The flies resulting from seed corn maggots are in the air these days and look like little, slow-moving, long-legged flies. Their eggs normally get laid in soils that contain decaying vegetation. Any plants seeded into those deposits can then accidentally be fed upon by those larvae.

Last week many of the corn plants in cornfields began to look ragged and like they had shortages on nitrogen.

After a poor corn-on-corn year in 2008 more growers were convinced they needed to be more proactive in responding to apparent lack of nitrogen. Thus what we are now seeing is plants that are uneven in growth and yellowing. Possible causes include having part of the applied nitrogen leach below the still-shallow root; or having part of the nitrogen soaked up by the bacteria as they began decomposing the 2008 residue; or the roots simply not reaching the applied fertilizer zone yet.

Thus it was time to get spring N samples taken if that was on the agenda, or get the sidedressing completed if preplant applications left gaps between what was projected for needs versus what had been applied.

The corn crop

Even though there have been few hot days there have been enough heat units received to push the first planted corn plants into the V5 6 leaf stage in central Iowa and taller in southern Iowa.

This is a critical stage in that the plants have entered the rapid growth stage and begin to elongate the internodes. The plants will soon be adding up to 2.5 leaves per week if GDU accumulation is great enough.

More of the fields are now in the V3 – V4 growth stages and are slowly adding top and root growth. More heat would help, especially now that there are no moisture shortages across the state. Projected tasseling dates for many fields are in the July 5 to July 10 time period, which is typically favorable to yields.

At V4 the corn plants were at the stage where the number of kernel rows around was being determined. Ohio State University research data suggest that the plants need to maintain a critical phosphorous level to maximize growth and that kernel row number. A number of growers who subscribe to that thinking either placed P fertilizer or foliar sprays to boost P levels and corn yields.

It is also interesting to dig and see how long the roots have grown. The normal assumption is that the roots should be as long as the plants are tall. In strip tilled and placed fertilizer fields it is not unusual to find roots that are about twice as long as the plants’ heights. Those roots should be covered with dirt when they are dug out and long and white after being washed. It is a good sign when they are covered with dirt as that indicates that plenty of root hairs are present. Those root hairs multiply the root surface area and increase nutrient uptake.

We used more of a biological product called Bio Pack to boost root growth, root hair number, and interaction with beneficial soil microbe populations. In nearly every Midwest dryland field, the person who grows the biggest root harvests the most grain.

Agenda

There are many things to get done in this expected marathon season. Most growers are running their sprayers long hours to get any weeds and unwanted grasses under control. One thing to remember is that grasses and many weeds have their preset germination window that is temperature and timing related.

Knowing those windows helps a person make better decisions about what weed control responses are required and justified. This year more farmers applied residual herbicides on their herbicide tolerant corn, thus wish to get by with only an application of their non-selective products.

Growers who have been achieving their desired yield goals are being proactive and doing what it takes to help their plants lose some of their apical dominance.

Bean plants that are still in the unifoliate growth stage risk not having enough branches to form the 20 podded nodes on the main stem to yield well.

Thus manipulating hormone levels early can help the plants form the four or five side branches needed to hold the desired pod number.

Achieving that goal is done using early foliar applications of phosphate, sugar, micronutrient, and hormone mixes.

Good luck in getting everything done.

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