field
shot - deep planted wheat #1
Pictures of deep planting:
field
shot - deep planted wheat #1
field
shot -deep planted wheat #2
roots
and shoots - wheat plants planted too deeply
Hosts: Possible in all crops
1) Elongated subcrown internode
2) Uneven emergence and stand
3) Yellow stems and leaves immediately below the soil surface (1).
Look-alike symptoms:
1) Salt damage
5) Herbicide injury due to dinitroanilines (Edge, Prowl, Sonalan, Treflan)
6) Herbicide injury due to thiocarbamates (Avadex BW, Far-Go) (1).
Favorable conditions: Injury can result when seed is planted too deeply (a guideline is 1.5 to 2.5 inches deep for tall varieties and no deeper than 2 inches deep for semi-dwarf varieties). Wheat plants that emerge from deep planting may expend much of the energy reserves stored in the seed just trying to get out of the ground. The result is weak and stressed seedlings that are more susceptible to emergence problems from crusting, disease, insects, and adverse environment. The deeper a seed is planted, the more water is required to get the seed out of the ground. The following table demonstrates the amount of water need to allow 100 lb seed/acre to sprout at different planting depths:
SEEDING DEPTH WATER REQUIRED FOR SPROUTING SOIL EXTRACTION1
1 inch 5 gallons 400-450 lb
1.5 inches 30 - 40 gallons 1500-1800 lb
3 inches 50 - 55 gallons 1-1.5 tons
1 At field capacity, the amount of silt loam soil from which all available water must be extrated.
Wheat is often seeded to moisture, but as the depth increases, the problem for seedling emergence from greater depths is therefore compounded both because of th emarginal soil water supply and because it takes more water to get the shoots out of the ground.
Pattern in field: The entire field will show spotty and thin stands if the drill is not set properly. Most susceptible areas will often be in a rough, uneven seed bed where cloddy soil conditions and variable soil conditions exist.
Infestation levels:
History in MT and US:
Crop losses: If the plants cannot break through the soil surface, they will die as seedlings. Yield will depend on evenness of the final stand, variety planted, plant density, environment, and growing conditions for the remainder of the growing season. Increased tillering can partially compensate for reduced stands (1).
Controls: Set drill to seed at 1.5 to 2.5 for tall varieties and no deeper than 2 inches for semi-dwarf varieties.
References: 1) Guide to Herbicide Injury Symptoms in Small
Grains. Second Edition. 1992. Agri-Growth Research, Inc., Hollandale,
MN, p.45-46.
Potential problems:
- Seeding spring wheat after the weather turns hot causing seedbeds to dry rapidly is called late seeding. After mid-May, seeding conditions generally deteriorate on the high Great Plains.
- The rate of seedbed water loss when daytime temperatures climb above 70 F is quite high.
- Dark soils lose absorb heat causing increasing rates of water loss.
- Rough surfaces stay cooler from shading and greater area exposed to evaporation processes, but with their loose structure, they also may dry deeper (1).
Pattern in field: Damage to existing winter wheat stands often is spotty in the field (5). This makes the replant decision more difficult. See Stand Evaluation, Replant Considerations below.
Stand evaluation: Replant considerations:
STAND EVALUATION
Reseeding should be considered if 50% or more of the plants in a field are dead or dying. Such plants have few roots and the stem below ground level is brown and rotten in appearance when cut open. Another method for evaluating a winter wheat stand is to determine the number of plants per square yard. Do this in 10 or more locations in the field. Fields having an average of 55+ plants in a square yard should not be replanted (5).
REPLANT CONSIDERATIONS
1. There are no guarantees that replanting wil provide a better stand.
2. The stand that is there is already ahead of the replants.
3. Replanted seed will need water immediately (rain or irrigation).
4. Typically, the later the replanting date, the hotter the soil temperatures. Consequently, there are more problems with crusting, diseases, insects, and weed pressure.
5. Seed costs increase.
6. Chances of soil compaction increase.
7. Research has shown that 80% of the time, the decision to replant was wrong.
If it is necessary to reseed large areas, work the section of the field to be reseeded in a rectangular shape. The area then can be seeded and harvested separately. This will avoid spring and winter wheat mixtures, which will be discounted at the market. Calibrate drills to plant 20 live seed per square foot. Use the highest quality seed available (5). CAUTION: Rapid planting of a new wheat crop after tilling an existing stand will greatly increase the chances of wheat streak mosaic moving to the emerging wheat. Losses generally are most severe when wheat is infected just after emerging.
History in MT and US: Winterkill of winter wheat and wet spring conditions that prohibit early spring seeding often force Montana growers to late seed spring wheat.
Crop losses: Late spring planting can result in later maturity and exposure to hot, dry weather during the pollination period. Lack of good pollination can result in lower yields even where plant population, fertility, and water availability all suggest a higher yield potential (4).
Seeding guidelines: Common late seeding mistakes are seeding too deep, inattention to packer wheel operation, and seeding too fast. High speeding in the late season is a natural tendancy. However, as seedbeds dry, equipment performs differently usually through loss of seeding depth control. Higher speed increases this problem especially with spring loaded double disc drills. These units have a tendency to both bounce and seed shallow across hard spots at higher operating speeds. Packer wheel load settings need attention as soils dry and clods harden. When seed cover consists of coarse and loose material, the potential for drying is increased. Proper packer wheel settings is an art achieved through trial and error. As a guide, the packer wheel setting is about right when soil density above and below the seed are indistinquishable (1).
Resistant varieties:
References: 1) Helm, J.L. 1994. "Late seeding - an art and some
common mistakes" North Dakota Crop and Pest Report. 5/19/94 No.
3. 2) McClurg, T. May 1994. "Over the coffee cup" Western Roundup.
Western Sugar Co. 3) Bowman, H. and Cash, D. Sept. 1994. "How late can
you plant winter wheat?" MSU Extension Service news release. 4) Riesselman,
J. Lower than expected spring wheat yields. Montana Crop Health Report,
October 4, 1991, No. 13. 5) Jensen, G. Recommendations for reseeding. Montana
Crop Health Report, May 5, 1989
Guidelines:
In a normal year, the Montana Agricultural Experiment Station recommends winter wheat plantings to be made before October 10 to promote tillering and winter survival. However, in years were there is very low soil moisture at this time or other prohibitory factors exist taking several precautions can increase the odds for success. Producers in central Montana can probably plant winter wheat until mid-November. However, producers insuring their crops should check with their insurance company before deciding to plant after October 15.
When late seeding winter wheat, consider the following:
1) Seed at normal depths.
2. Some research suggestes that tall varieties may do better than short varieties when seeded deep. However, this has not been tested in Montana (Phil Bruckner).
3. For late seeded winter wheat, seeding rate should be increased from the conventional 60 lbs/acre to 70 lbs/acre.
4. On summer fallow, planting into dry soil should be no major risk. However, on re-cropped ground, producers should be cautious on planting winter wheat after barley. This is because of the potential of contamination of the wheat crop by 1994 barley that has not yet sprouted (Dave Wichman).
5. Consider applying phosphorous which is beneficial for winter survival, but reducing nitrogen until the stand is assessed the next spring (Dave Wichman).
6. Use seed treatments for winter wheat planted into dry soil to substantially reduce dry seed decay problems (Jack Riesselman).
7. Cheatgrass is the only weed that has the potential to compete heavily with winter wheat that is seeded into dry conditions. If the cheatgrass was properly controlled during the summer fallow season, cheatgrass problems likely be minimal in the winter wheat crop. However, if you plowed down cheatgrass heads in summer fallow ground, viable seed is present in the soil and will not emerge until it rains. After it rains, tillage or a low rate of glyphosate (i.e., Roundup) will control it (Pete Fay) (1).
References: 1) Bowman, H. and Cash, D. Sept. 1994. "How late can you plant winter wheat?" MSU Extension Service news release.
1. There are no guarantees that replanting wil provide a better stand.
2. The stand that is there is already ahead of the replants.
3. Replanted seed will need water immediately (rain or irrigation).
4. Typically, the later the replanting date, the hotter the soil temperatures. Consequently, there are more problems with crusting, diseases, insects, and weed pressure.
5. Seed costs increase.
6. Chances of soil compaction increase.
7. Research has shown that 80% of the time, the decision to replant was wrong.
Reference: McClurg, T. May 1994. "Over the coffee cup" Western Roundup. Western Sugar Co.
Hosts: Most crops affected depending on severity of compaction.
Symptoms:
1) Uneven stand
2) Roots grow parallel to compaction lines
3) Root system can be reduced
4) Visible traffic patterns as indicated by plant growth (1).
Look-alike symptoms:
1) Herbicide injury due to benzoic acid in the soil (Banvel, Banvel SGF)
2) Herbicide injury due to dinitroanilines (Edge, Prowl, Sonalan, Treflan)
Favorable conditions:
1) Working wet soil
2) Use of heavy equipment
3) Lack of organic matter in the soil which prevent airspace for proper root development (1).
Pattern in field: Areas with added equipment traffic, such as end rows, field roads, and driveway are likely to show injury. Also, soil compaction problems are common in areas that were worked when wet, areas low in organic matter, and areas high in clay or sand content (1).
Infestation levels: Some recovery can occur if plant roots can penetrate the compacted zone to reach moisture and nutrients (1).
History in MT and US: Soil compaction occurs fairly commonly when favorable conditions exist. For example the rimrock areas near Billings historicallly have had hardpan problems.
Crop losses: Final yield will depend on severity of compaction and growing conditions throughout the season (1).
Controls:
Cultural controls:
Resistant varieties:
Biological controls:
Chemical controls:
References: 1) Guide to Herbicide Injury Symptoms in Small Grains. Second Edition. 1992. Agri-Growth Research, Inc., Hollandale, MN, p.45-46.