Observations From The Field

Freezing temps do not deter Roundup Ready prospects

Published online: Jan 01, 2009 Feature Howard Binford
Viewed 73 time(s)
The introduction of Roundup Ready Sugarbeets into Amalgamated Sugar Company's growing areas in the spring of 2008 got off to a very rough start.
As spring planting approached, it became questionable if there would be adequate supplies of Roundup Ready Seed to meet the demand.
The cost of seed, with Monsanto's tech fee included, had growers questioning if Roundup Ready Beets were really worth it.
Some were considering sticking with conventional varieties. Then came the "Spring of 2008."

It was undoubtedly the coldest, latest spring I can remember, breaking many freezing temperature records throughout most of April. As the freeze warnings continued, it seemed there never would be a good time to plant sugarbeets this year.

As a result of the cold weather, stands were thin in the majority of both originally planted and replanted fields.
Emergence dates, and therefore beet size varied greatly within each field. And fields with areas that blew out late in the planting season became patchwork quilts of Roundup Ready Sugarbeets and Roundup Ready Corn.
Although each year has its own unique challenges and problems to overcome, this year was especially difficult. The following are observations of agronomic practices that worked and some that didn't.

PLANTING

When planting early, soils are often a little too wet and the heavier air planters, such as Monosem and J.D. Maxemerge often compact the top of the seedbed as well as the sides of the seed trench.
The V press wheels then push this compacted wet soil together to close the seed trench. As the soil dries, it cracks laterally from the seed trench, as well as along the center of the seed trench allowing the soil to dry closer to the seed.

Also, as the soil dries, it becomes very hard. When this situation occurs, emerging seedlings struggle to get up; often they kink and curl, or grow sideways looking for a crack to come through. Final stands are usually thinner, many seedling beets don't make it and the beets that do are often weaker and slower growing.
A good solution to this problem that worked very well this spring, is to replace the V press wheels of the Monosem or Maxemerge planters with Posi Close Wheels, manufactured by Schlagel Manufacturing, Inc. Torrington, Wyo.

The Posi Close Wheel breaks up the compacted soil over the seed row created by the planter depth wheels and the disc opener.
It firms the soil around the seed and leaves a layer of mulched soil over the seed row. It was used on 450 acres in the Nampa area. The beet seedlings emerged through this mulched layer much more uniformly, resulting in some of the most uniform emergence, consistent and vigorous stands I saw this spring.


ROUNDUP APPLICATION

Monsanto's recommendation for the first Roundup application after beet emergence is 2-2-22.
Which, when translated means, make the first application of Roundup at the rate of 22 oz. per acre when EITHER, the sugarbeets have two true leaves OR the weeds are two inches tall, which ever occurs first. (This recommendation assumes the field is free of weeds prior to sugarbeet emergence.)

It then goes on to say, when timely applications cannot be made and weeds become large and /or weed populations are severe, the application rate of Roundup can be increased to 32 oz./acre. Subsequent applications should be made before weeds reach four inches in height.


WHAT HAPPENED IN 08

This year the timing of the 2-2-22 didn't work that well except in fields that were either planted later or fields that were replanted.
In the majority of beet fields in Amalgamated's growing area, the first application of post emergence Roundup was applied too late. Mostly because of weather-related issues such as: windy conditions that delayed spray applications, freezing and generally cold temperatures, slow, erratic emergence of the beets, wet soil from irrigation to improve beet stands and competition from other crops for use of the spray equipment.

Whatever the reason, most fields didn't get sprayed until the beets were closer to 6 - 8 leaves, the weeds were often four inches or more and the application rate was often too low for the situation.
Although, in most cases these weeds were controlled with subsequent applications of Roundup, this situation is not desirable. Controlling these weeds required additional trips with the sprayer and extra expense.
The maximum potential beet yield was reduced because of weed competition for moisture and nutrients. And there is increased potential for development of Roundup resistant weeds.

Fields that were planted later or fields that were replanted received applications of Roundup that were more timely and consistent with Monsanto's recommendation.
First applications were made when the beets were closer to two true leaves, before the beet leaves protected small weeds from Roundup spray and when the weeds were less than two inches tall and easier to kill.
Also, instead of the 22-ounce per acre rate, the first applications ranged from 26 to 32 ounces per acre.

In this situation, fields with adequate stands of beets and moderate weed pressure received two applications of Roundup and one early application of Outlook following the dammer diker and remained weed free at row closure.
Although weather conditions were a major factor affecting timeliness of spray applications in these two scenarios, several growers have commented that it's important to get control of weeds earlier than they did this year to avoid weed escapes under the beet canopy.


The weed escapes had to be controlled in mid- to late-July when growers didn't want to be in their fields spraying.
Fields were wet from irrigations and had to be dried out, and beet canopies are closed at this time of year.


PROCEDURES TO USE

Following are a few procedures that were used by growers this year and worked well to achieve desirable weed control results:

 Started with a weed-free field at planting time, with the use of mechanical tillage or clean sweep Roundup application(s).

 Made the first post-emerge Roundup application when:
? Beets were small, 2 true leaves, and before the beets exceeded the weeds in size; ? Weeds were small, sprayed before weeds exceeded 1 1/2 inches;
? Used a high enough rate to kill the weeds that were present (up to 32 oz./ac).

 Kept the fields clean up to row closure with the use of:
? Subsequent Roundup application(s);
? Use of drop nozzles works when weeds are under the beet canopy.
? Use of Lay-by herbicides such as Outlook, Treflan, Eptam.
? Especially in fields with thin stands or blank spots. Otherwise you may be spraying Roundup all season long to control late emerging weeds in these areas). (Fig. 12, 13)

 Used the full rate of ammonium sulfate (17 lbs./100 gallons) with Roundup.

 Used 10-15 gallons maximum of water per acre, some had best results with 10 gallon.

 Use of a sticker helped control lambsquarter.
Although this has been a difficult first year for Roundup Ready Beets, growers are generally satisfied with them at this point. They like the ease of weed control, and the cost savings from fewer trips over the field.

They can see the potential for even more savings as we learn better ways to use the Roundup technology and other technologies such as strip-tillage.



Editor's note: Binford is an agriculturalist for Amalgamated and can be contacted by email at hbinford@amalsugar.com.