January 05, 2018
Wheat Variety Selection and Placement for the South
- In addition to yield, the farmers consider several performance characteristics including height, maturity, and disease tolerance when selecting a wheat product.
- Wheat products should be selected to perform in the landscape and climate of each southern geography.
Variety Selection for Risk Management
Southern wheat classes include hard red winter wheat. Each class has particular characteristics that make it successful in southern geographies. Within the wheat class grown, farmers should select several products with a range of maturities and disease tolerance for the agronomic plan of the farm.
Texas Blacklands - According to local technical agronomists (TAs) and Technical Development Agronomists (TDAs), rainfall is approximately 20 inches or greater during growing season. Planting time is normally November 1st to December 10th, and harvest is May 1st to May 15th. Late winter and spring moisture (wet conditions) normally drives disease, and lodging is a big issue. Most important diseases are normally stripe rust and powdery mildew. Throughout the years, agronomists have observed yields ranging from 50 to 70 bu/acre for managed acres. Later plantings have a very short dormancy period and if planted too late may not vernalize. However, later plantings are less likely to be damaged by late spring freezes. Moisture is normally adequate to above adequate for a usually short fill period. Soils are generally heavy and hold water quite well but also can have standing water due to slow intake. Soil is alkaline in all areas with an approximate 6.5 to 7.8 pH range and 1 to 2% organic matter in areas based on soil tests.
Rolling Plains - Rainfall is highly variable, and based on TA and TDA knowledge and experience in the area, 8 to 15 inches noramlly falls during the growing season. Planting is typically September 25th to November 15th. Early plantings are almost exclusively for grazing. Many acres of wheat are beardless (awnless), and used for grazing instead of grain. There are limisted irrigation acres. Based on TA and TDA experience, normal yields range from 25 to 35 bu/acre on dryland, and harvest normally falls between May 10th and June 1st. Key diseases are the rusts. Hessian fly is another important pest and has become much worse due to no till wheat-on-wheat. Mild winters promote edd laying almost the entire growing season. Heat during grain fill is one of the biggest hindrances to wheat yields. Grain fill is often cut short due to the hi temperatues during the mid to later grain fill. Soils range from very heavy to very sandy. Typically, soils are observed by TAs and TDAs as having a 7 to 8 pH, and organic matter range around 1 to 1.5%. Soils are prone to drought in this region.
High Plains - Dryland fallow and irrigated production. Dryland rainfall is highly variable (8 to 12 inches) with most areas experiencing dry conditions during the growing season. Most dryland wheat is planted on fallow acres unless it is a very wet year. Annual rainfall on the high plains is approximately 15 to 18 inches based on TA and TDA knowledge and experience in the area. Annual cropping is very precarious given high summer temperatures, low humidity, and windy conditions. Soils are mostly medium to coarse textured with high pH and low organic matter. Planting begins in mid September and ends on the southern high plains near November 15th. Most wheat is planted on the northern high plains north of Amarillo, Texas but can be planted as far south as Lubbock. Fill periods are longer on the high plains than other areas because of lower night time temperatures resulting from the high elevation (greater than 3,000 feet). Longer maturity wheat varieties generally perform best due to the longer fill period. Harvest will begin in early June and can often extend into late June and early July depending on the year. Harvests are progressively getting earlier due to the warm winter conditions. Late spring freeze damage is a major concern. Irrigated wheat is common on the high plains. It is normally planted very late after corn is harvested. Yields greater than 80 bu/acre may be achieved in productive years under irrigation.
NC Oklahoma/SC Kansas - This area has higher rainfall and typically has higher yields. Based on TA and TDA experience in the region, average yields are around 45 bu/acre but can exceed 80 bu/acre. Rainfall during the growing season that stretches from October 1st to mid June with rainfall ranging from 15 to 18 inches during the normal growing season. This geographic region is characterized by soils with medium texture and low to very low soil pH, with low organic matter. Wheat products tolerant to low soil pH should be planted to maximize performance.
The majoirty of planted acres are continuous wheat on wheat, but rotational acres behind corn and canola are becoming more common. Rust is present at some level most years but diseases such as tan spot and Septoria may be found in almost every field each year. Wheat scab is becoming more important due to the number of corn acres preceeding wheat. Soil-borne mosaic virus is another key pathogen that is endemic in this area, and wheat products should have genetic resistance to this disease.
Late-season freeze damage is a major cause of reduced yields. Some freeze damage has become an annual problem. Later maturing wheat varieties - and ones that hold their dormancy better in the spring - may be planted to lessen the likelihood of late freeze damage.
Hessian fly is particularly problematic but damage may be reduced with seed-applied insecticides and later planting combined with genetic tolerance. This area probably has more agronomic issues than other areas of the southern plains but is a good wheat production area due to the higher rainfall.