ISSUE 1 May 15, 2008
High sunflower yields require attention to detail. Sunflower prices are attractive and growers are looking to maximize the profit potential of the farm. Sunflower fits well into a small grain cropping rotation. Planting a broadleaf crop in rotation with small grains can provide a means to reduce certain diseases in wheat and durum including tan spot, septoria and certain root rots.
Selection of the sunflower hybrid should be based on test results showing high yield potential, disease resistance, and high percent oil content. Seed germination should be high and seed size uniform with no cracking. Timeliness is the key to all good crop management. Long term optimum planting dates for sunflower in ND have been from May 20 to June 5th although yields are generally higher with mid-May to late-May planting dates compared to June planting dates in most ND locations. The sunflower crop will mature in about 95-110 days after emergence.
Special attention should be given when seeding the sunflower crop. Correct plant populations depend on soil type and moisture conditions. Oil sunflower plants per acre should be around 20,000-22,000 plants on heavy soils and 16,000-18,000 plants per acre on lighter soils and low rainfall areas. For confectionary sunflower, recommended populations are lower. For solid seeded sunflower the desired population at harvest is around 26,000 plants per acre. To obtain these recommended populations overplant by 15 percent.
Under dry conditions producers may want to reduce the plant populations because if a drought occurs during the growing season high sunflower populations may exhibit severe signs of moisture stress including small heads.
Plant to a depth of 1.5 to 2 inches if moisture is available in the top soil. Seeds can be placed deeper under dry conditions, but not more than three inches. Larger sized seed is best for deep seeding.
During the sunflower survey in the fall of 2007 plant stand and uneven distribution were identified as two reasons for lower production. Even seed distribution is critical. Therefore it is important to check the planting depth and seed drop at planting time. Driving too fast may cause skips and irregular seed placement. A good start to the season begins with attention paid to planting. It is also important to monitor the crop for insect problems from early emergence throughout the growing season.
Major North Dakota Yield Limiting factors in sunflower-2007
(National Sunflower Survey D. Berglund)
Plants too close together will compete with each
other. Proper distribution of plants is essential to
achieve maximum yields. (Photo by Hans Kandel)
MANAGING POOR STANDS OF WINTER WHEAT
The cool spring weather has slowed the development of winter wheat this spring. Nevertheless, now is the time to access winter wheat stands and make decisions on what to do to when stands suboptimal. In the eastern part of the state where snow cover was excellent during the winter, winter wheat appears to have survived the winter well and many fields are showing excellent spring vigor. In parts of the state where fall establishment was limited by poor moisture and where there was little snow cover during the winter; reports of winter survival are more variable. The questions now are what constitutes a poor stand and how to manage fields that have sub-optimal stands.
Plant stands should be accurately assessed before determining an appropriate action. At first glance plant stands can look worse than it really are. When winter survival is not uniform, focus only on those parts of the field that will likely need replanting. Within these parts of the field count four or five randomly selected areas using a square yard quadrant or something similar with a known area. Winter wheat has the ability to tiller and fill-in gaps better than other classes of wheat, especially if the weather is cool and moisture is not constraining and fairly large reductions in the optimum plant density can be tolerated before it becomes more profitable to replant small grains. For winter wheat, consider replanting when stands are below 5-10 plants/ft2. If you decide to replant the entire field with spring wheat, use a higher seeding rate to compensate for reduced tillering if planting occurs after May 20th. You should also consider using early maturing varieties (varieties from SD tend to be among the earliest adapted to ND) or a variety that is known to handle the heat (i.e. Steele-ND and Howard are NDSU releases that handle the heat well). For fields with small patches of poor stands the best option is probably to leave the field and do a good job of weed control. For fields with very large patches with few or no plants, planting something to reduce weed growth and soil erosion is recommended. Some farmers have reported good results form planting spring wheat to fill in such gaps. Nevertheless, spring wheat matures later than winter wheat so harvest can be problematic. Furthermore, mixing wheat classes can cause problems at the elevator. Planting winter wheat into large gaps can also be an option. Winter wheat planted in the spring will not vernalize so it will not produce a head, but will provide ground cover until harvest.
Remember that any tillage in the dry parts of the state will further dry out the soil, making the establishment of spring seeded crops difficult. Check with your crop insurance agent before destroying your wheat field.
Extension Agronomist for Cereal Crops