[Grainssoybeans] Wheat Planting

— Written By Curtis Fountain and last updated by
To:  Duplin Co. Wheat Interests
From:  Curtis D. Fountain
            Agricultural Extension Agent – Field CropsVariety Selection
Attached is 2013 Wheat Variety Performance & Recommendations prepared by Dr. Randy Weisz and Dr. Christina Cowger. This information was included in a August 2 email. Please consider yield, heading date, disease resistance, etc. in variety selection decisions. To reduce freeze damage risk, plant at least 1 late heading date variety and no more than 1 early heading date variety. In Duplin County, powdery mildew, leaf rust, and soilborne mosaic virus are common diseases.

Planting Dates
For upper half Duplin County, wheat planting should begin October 20-25. For lower half Duplin County, wheat planting should begin October 25-30. The noted dates are early enough to insure warm weather to promote tillering. The noted dates are late enough to avoid excessive growth and high risk to insects/diseases. Plant early heading date varieties 2 weeks later than the dates noted. If litter is preplant incorporated and used as the wheat fertilizer, plant 2 weeks later than the dates noted.

pH & Fertilization
NCDA&CS Soil Test wheat lime recommendations are designed to raise the soil pH to 6.0 for mineral soils, 5.5 for mineral-organic soils, and 5.0 for organic soils. If soil pH is too high, micronutrients such as manganese can become unavailable. To achieve maximum yield potential, the soil pH, phosphorus index (P-I), potassium index (K-I), sulfur index (S-I), and manganese index (Mn-I) should be within proper levels at planting. Waiting until January (or later) to meet wheat P, K, S, or Mn needs is a good way to miss maximum yield. For maximum yield and test weight (if planting on time), 15-30 pounds/acre of at-plant nitrogen is critical.

Seeding Rate
Proper seeding rate is important. If planting on-time with 90% or better germination seed, the recommended target seeding rate is 1.3-1.5 million seeds per acre. Note the chart below for additional information.

Million seeds per acre:      1.31           1.52
Seeds per square foot:       30              35
Seed size                     Pounds of seed
(seeds per pound)                    per acre
10,000                      131             152
11,000                      119              138
12,000                      109              127
12,500                      105              122
13,000                      101              117
14,000                       94               109
15,000                       87               101Drill row spacing                        Seed
(inches)                     per drill-row foot
6                           15                  17
7                           18                  20
7.5                         19                  22
8                           20                  23
The above rates should be increased 20% for no-till plantings. Increase the above rates 13% if using 80% germination seed. Increase the above rates 4-5% for each week planting is delayed beyond the dates noted earlier in this email.
Click here for a 13-minute grain drill calibration video.
Planting Depth
Wheat seeds should be planted 1 – 1 1/2 inches deep when soil moisture is adequate, and slightly deeper if moisture is deficient.
Planting Wheat After Grain Sorghum
Grain sorghum leaves a chemical in the soil that can hurt wheat. Little is known about it and data is limited. The problem is most severe in no-till wheat following grain sorghum. Some reports have shown up to a 25% yield reduction when no-till wheat follows grain sorghum. Some reports have shown less. Tillage helps. Yield reductions in tilled wheat following grain sorghum have ranged up to 10%.

If planting 2013-14 wheat on 2013 grain sorghum land, use glyphosate to kill the grain sorghum plant prior to harvest. This assumes live, green grain sorghum foliage is present for glyphosate uptake. 90% brown head should be present prior to glyphosate application. Be prepared to harvest the grain sorghum 14 days after glyphosate application. For 4 lb formulated salt/gallon products, the glyphosate rate is 64 ozs/acre.

Remember grain sorghum is a perennial plant. An untreated plant will continue to grow until freezing temperatures kill it. Glyphosate will kill the plant and stop production of the harmful chemical.

Unless enrolled in a no-till conservation program, till/incorporate the grain sorghum residue after harvest to hasten decomposition.

Please call if you have questions.

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