ISSUE 4   June 4, 2009

ROLLING DRY BEAN AND SOYBEAN GROUND

Over the last few years there has been an increased interest in direct harvesting dry beans. With direct harvest it is important to have the cutter bar as close as possible to the ground. On rocky ground there is a danger that the combine will hit or pick up a rock, which may cause major damage to expensive equipment or delay the harvest.

The objective of rolling dry bean and soybean ground is to push rocks and large soil clods down to the soil surface and level the soil to allow a low combine cutter bar height during harvest. This will reduce harvest loss by cutting dry bean or soybean stems below pods instead of cutting above or through low pods and leaving seeds in the field. An additional benefit is that at harvest time producers can concentrate on the harvest without feeling the stress of watching for rocks in the field. Dry bean or soybean fields are rolled with large rolling drums after planting, either pre-emergence or post-emergence. The advantages of rolling before the crop has emerged are low potential for plant injury and improved seed-to-soil contact. The disadvantages include increased potential for soil-surface crusting and soil erosion due to wind action. As this planting season is short a lot of activities are taking place at the same time. Although producers may have good intentions to roll the field before emergence other field work or rain may prevent timely rolling of the field.

Rolling fields can be done after the crop has emerged, but will potentially cause plant injury including crushed leaves and cracked or broken stems. Plants will die if the stem is broken below the cotyledon leaves, due to loss of all growing points. Injured plants may be more susceptible to lodging and disease. Producers should be careful not to double roll areas of the field as this will cause excessive plant damage and potential compaction.

Dry Bean: Limited research data from Canada (http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex8817) found no significant differences in stand or yield comparing no rolling with rolling after seeding, rolling 3 to 5 days after emergence, or rolling 10 -13 days after emergence. However, there were broken bean hypocotyls arches when beans were rolled 3 to 5 days after emergence. Researchers concluded that the dry beans should be rolled either right after seeding or after the plants have straightened (no hypocotyl arch).

Soybean: NDSU research and farmer testimony indicates that rolling between the cotyledon and first trifoliate stages of soybean should limit injury potential. Also, rolling during the warmest part of the day with less turgid plants may reduce injury potential.

Table 1. Soybean yield after rolling at different growth stages, Carrington ND.

Plant stage of rolling

2003 Soybean yield
in bushel per acre

No rolling

29.2

Pre-emergence

30.9

50% of cotyledons emerged

28.7

Cotelydon

29.1

First Trifoliate

30.8

Mean

29.7

LSD 0.05

NS

Soybean rolling trials were conducted three years (2001, 2003, and 2004) at the NDSU Carrington Research Extension Center. There was a trend of plant population decline as rolling was delayed from pre-emergence to the first or second trifoliate stage. Untreated soybean and pre-emerged rolled soybeans showed no visible injury. Rolling soybeans that had fewer than 50% of the cotyledons emerged, were at the cotyledon stage, or at the first trifoliate stages showed less than 5 percent injury. Early morning rolling of plants at the 3-4 trifoliate stages caused the most visible injury when observed four weeks after rolling as compared to all other treatments. Post-emergence rolling in the afternoon on warmer days is likely to cause less damage to soybeans as the soybeans are less prone to stem breakage compared to early morning when the plant cells are filled with water. Soil conditions, tractor tires, and other factors may also contribute to injury. Soybean seed yield was similar among the unrolled check and rolling treatments.

Research results in Minnesota in 2008 (DeJong-Hughes; www.smallgrains.org/PGConf08/DeJong08.pdf ) indicated that soybean plants are somewhat protected from damage if there is previous crop residue on the soil surface. Later rolling caused more plant damage, but rolling did not significantly change soybean yield. Damage to the plants due to the wheel traffic was greater than damage by rolling itself. DeJong-Hughes also found that there is a higher potential for the soil to seal after rolling if adverse rain events take place.


Injured soybean plants by rolling.

Hans Kandel
Extension Agronomist, Broadleaf Crops
hans.kandel@ndsu.edu

Greg Endres
Area Extension Specialist
gregory.endres@ndsu.edu

 

MANAGING PREVENTED PLANTING ACRES AND PLANTING A RESIDUE CROP FOR WINTER WHEAT

Though great strides were made in planting this past week, many acres remain to be planted. Some of these acres will not be planted due to the lateness of the season and the continuing problems of excessive soil moisture and/or heavy corn residues from last fall. The last planting date for full insurance coverage has now past or will soon pass for most crops. Acres that will not be planted may be eligible for payments under prevented planting provisions of crop insurance. In order to maintain eligibility for DCP programs, acres that have not been planted must be protected from wind and water erosion, and must be maintained to control the propagation of weeds. Fields that receive a prevented planting payment cannot be planted to an insurable crop prior to the ending date of its late planting period and any cover crop that is planted cannot be hayed or grazed until November 1st (growers should confirm the restrictions and guidelines of their specific policy). The following are a few options that are available to meet the guidelines described above (not an exhaustive list):

  • Maintaining crop residue and controlling weeds with cultivation or chemical fallow. For dryer areas of the state, this practice can conserve moisture in the soil. The obvious downside, however, for areas of excessive moisture is that there will be no plants to remove this moisture from the soil. Where high water tables are problematic, this practice will likely accentuate problems of soil salinity.
  • Establishing a solid seeded cover crop. Cover crops provide far better protection from water and wind erosion than cultivation and crop residues. Selection of a cover crop should be based on cost, ease of management, time of planting, and characteristic of the soils. Guidelines for selecting an appropriate cover crop will be discussed in future issues of this report.
  • Establishing a "residue" crop into which winter wheat is planted this fall. Successful winter wheat survival is largely dependant on good snow cover in the winter. Establishing an effective residue crop that traps snow can significantly improve the probability that there will be adequate snow cover for successful winter wheat production. To be effective, a residue crop must remain erect during the fall and winter. Cereal crops that do not reach the boot stage before being killed by frost or herbicides, for example, will lay flat on the soil and will not capture much snow. Given the restriction that a crop cannot be windrowed, grazed or harvested before November 1st if a prevented plant payment is received, the most effective residue crop is probably flax. Flax can be established as a lightly seeded solid stand, in wide rows (i.e. 3-4 feet spacing) or as strips. Strips of flax 3 to 5 feet wide and 15 feet apart have been found to effectively trap snow while minimally depleting soil moisture. When seeding flax in strips or in wide row spacings, the drill should be set at a high seeding rate (40-60 pounds per acre) and drill spouts should be taped shut to obtain the desired spacing. Strips of flax more than 20 feet apart can be risky as they do not catch sufficient snow in most years. Flax should be seeded on or about August 1 and no later than August 15, depending on the region of the state. Though some additional weed management will be needed prior to planting, flax planted in early August followed by winter wheat could be a viable and profitable option for dealing with land that was too wet to plant this spring.
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    Joel Ransom
    Extension Agronomist for Cereal Crops
    Joel.ransom@ndsu.edu

     

    WHEN SHOULD I HARVEST ALFALFA

    The prime objective in determining when to harvest is to obtain prime hay in the bale. This is especially true for cash hay producers and dairy operations where prime hay means greater net returns for the alfalfa crop, but it can be important for beef cow producers also as a source of high-quality high-protein hay to be used in rations with other low-quality hays like mature grasses or slough hay.

    Many factors enter into the decision of when to harvest alfalfa such as environmental conditions, other field work, insect infestations, etc. But what factor(s) should be used to determine when to harvest if these are not determining factors?

    Plant maturity or calendar date has been used extensively to determine the optimum time to harvest, but I believe plant height is more important in determining when to harvest than plant maturity and especially calendar date. The growing season changes the optimum time to take the first cutting. If the spring is late and the temperature average to below average, high-quality hay can be obtained by harvesting alfalfa at a later maturity stage, late-bud to early bloom, like in 2008 in the Red River Valley of the North when harvest started on June 16. But if the spring is early and above-normal temperature, the optimum harvest stage will be earlier like in 2002 when first harvest was taken on May 24.

    Plant height is the best indicator of when to take the first harvest (Table 2). Note that the relative feed value (RFV) (relative forage quality (RFQ) would produce a similar table) decreased from 220 to 149 as the plant height increased from 16 to 35 inches when all samples were taken at the early bud stage. A similar effect was seen at the early flower stage. Also note that the loss in RFV was much less when the maturity stage increased from early bud to early flower within a given height.

    At Fargo, we have found that harvest should begin whenever the alfalfa reaches around 28 inches in height, regardless of the maturity stage, if prime hay in the bale is desired. The estimated RFV in Table 2 is for alfalfa standing in the field. Be sure to allow about 25 to 30 units of RFV for harvesting losses; therefore, harvest needs to occur by 175 to 180 RFV. The best method to estimate the RFV or RFQ in the first harvest is to utilize a PEAQ stick available for purchase from the Midwest Forage Association.

    Table 2 also illustrates why harvest at early flower during the first harvest would be recommended when growth is less than 20 inches in height. Therefore, under drought when growth is reduced, waiting for a more advanced maturity stage to allow increased production would be a wise management strategy. But waiting for increased yield when growth is good leads to poor-quality hay. By harvesting early under good growing conditions, there is increased opportunity for an additional harvest that more than offsets the yield loss in the first harvest by harvesting early.

    Table 2. Estimated RFV by plant height at two maturity stages.

    Plant height

    Early Bud

    Early flower

    Inches

    -----------------RFV -------------------

    16
    20
    25
    30
    35

    220
    201
    181
    164
    149

    196
    181
    163
    148
    135

    Fields generally have varying maturity and height, especially in second and later harvests. Frequently hilltops have less growth and are more advanced in maturity than lower wetter areas of the field. Base your decision when to harvest on the valleys realizing that the short growth and more advanced maturity on the hilltops will not affect the quality extensively.

    Second and third harvests usually generally are shorter in height than the first harvest. Therefore, the optimum maturity stage at harvest will be more advanced than the first harvest. We have found that under a four-cut system, the maturity at harvest generally is mid to late bud and occasionally 80% bloom (under drought stress) in the second harvest and 10 to 20% bloom in the third harvest or later under drought stress. Again, maturity at harvest varies depending on the year and moisture level so itís best to use height to help decide when to harvest. For example, in 2006 the second harvest at 10% bloom had a RFV of 193 and the third harvest at 30% bloom had 250 RFV. Both of these harvests were under drought stress and plant height was only 10 to 12 inches in the third harvest. We should have delayed the third harvest to obtain additional yield in this case.

    Once you decide it is time to harvest, consideration should be given to time of day for harvest. Research has shown that harvesting in late afternoon or early evening produces a forage with a higher total nonstructural carbohydrate content than one harvested in the morning due to the current dayís photosynthesis. Higher carbohydrate levels increases digestibility and animal acceptability, which should result in improved animal performance.

    In summary, plant height is the best indicator to use in determining when to harvest, especially in the first harvest, but also in later harvests. Use of the PEAQ stick will help you make the decision as to when to harvest. Harvest in the late afternoon or evening to increase the carbohydrate content and increase the quality of harvested hay.

    Dwain W. Meyer
    Extension Forage Specialist
    dwain.meyer@ndsu.edu


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