The wheat-planting season is fast approaching. I have received numerous calls about the earliest date farmers can plant wheat.
Normally, wheat planting in Arkansas works best when seeded Oct. 1-15 in northeast region of the state, Oct. 10-20 in the central section, and Oct. 15-31 in southern Arkansas. These are the optimum dates; successful production does occur for planting up to two weeks later for each area listed.
Producers ask if they can plant earlier than those listed dates. A medium to medium-late maturity wheat can be planted up to one week earlier to avoid too much growth and the possibility of spring freeze damage.
Additional risk involves Hessian fly and aphids. Very limited research data indicates that a one-half rate application of Gaucho seed treatment protects against early-season aphid feeding — thus barley yellow dwarf should be minimal. Again, there is very limited data and the product would be used at the grower's risk since this is not a labeled rate.
Several growers have asked about the procedure for seeding wheat aerially into standing soybean. First, the stage of the soybeans must be evaluated. When the first yellowing of the soybean leaves is observed, aerially sow 180 to 200 pounds per acre of wheat seed.
It is very important that the wheat seed are placed on the soil and not the soybean leaves. If the soybean field is yellow, 25 to 50 percent of the soybean leaves have shed, and seed-to-soil contact will be compromised.
Medium maturity wheat is best suited for this practice.
Wheat variety selection is very important. Medium maturity wheat should be used when planting at the beginning of the planting window and early to medium-early when planting at the later half.
When picking a variety, evaluate yields over several different locations. Select a variety that yields well across several different locations and environments. Several varieties with differing maturities should be planted to spread the risk.
Soilborne mosaic virus is a problem in northeast Arkansas, and the only control measure is planting a resistant variety.
Grain quality at harvest is important. For the producer to obtain the highest grade, high-test weight varieties should be selected.
Once selected, the seed should be placed 1 to 1.5 inches deep at a seeding rate of 30 seed per square foot.
In no-till environments it is important to apply a burn-down herbicide to remove the emerged winter annuals.
Soil fertility is an important component of wheat production. A soil analysis indicating pH and nutrient levels is important. Wheat performs best at a pH greater than 5.7. Liming would be recommended when the pH is below 5.7 when rice is not in rotation. If rice is in rotation, liming would be recommended when the pH is below 5.5. Without proper pH, nutrient availability can be limited.
Nitrogen can be required in the fall when wheat is planted following corn, grain sorghum and rice. Normally, 40 pounds per acre of nitrogen is required to aid in the breakdown of the previous crop residue. The fall-applied nitrogen is not calculated into the spring nitrogen requirement.
The most important nutrient to promote tillering and growth is phosphorus. This is especially true if the soil pH is approaching 7 since phosphorus will combine with calcium and become insoluble and unavailable to the wheat plant.
Split applications of phosphorus in the fall and spring increase utilization. The split is normally 50 percent with the spring application utilizing DAP (18-46-0). If nitrogen is required in the fall, DAP is the product of choice. DAP is much more water-soluble than triple super (0-46-0), thus there is a more-rapid utilization by the plant.
Potassium is usually not a limiting nutrient to wheat, but it is needed for double-cropping to soybeans.
Sulfur is normally required in the spring, but some sandy locations along the river system do show sulfur deficiencies in late fall if heavy rainfall has occurred.
Excess water is detrimental to high-yielding wheat. Drainage is the most important cultural practice in Arkansas. More wheat production occurs each year on raised bed to promote drainage. This practice is very successful on slope-graded fields. On flat-planted fields, drain furrows should be placed 20 to 40 feet apart on diagonals.
Field drains and ditches should be unobstructed to allow free movement of the water. A four-wheeler and shovel after the first big rain can pay tremendous dividends as you evaluate the efficiency of the drainage system and correct it where necessary.
William Johnson, is a field sales agronomist for Pioneer Hybrid International.