Research has shown wheat-sorghum-fallow rotation or continuous sorghum is the most profitable cropping system for dryland grain production on the Texas High Plains. Research has also shown no-till or minimum-till sorghum outperforms conventional tillage due to soil moisture preservation.
Dryland sorghum fertility guidelines should be built on soil testing and yield goals based on depth of subsoil moisture at planting. Heavy soils with more than 1.3% organic matter (OM) need 1.0 pound nitrogen per bushel yield goal or 1.8 pound nitrogen per hundredweight yield goal. It is recommended that sandy soils with 1.3% OM or less receive 1.2 pounds per bushel or 2.1 pounds nitrogen per hundredweight yield goal.
Phosphorus (P) is recommended for low and very low testing soils. When soils test in the medium range, applying phosphorus should be considered if subsoil moisture is available (4-6 feet) at planting. Potassium (K) should be applied only if the soil test is low. Most High Plains soils have adequate potassium for dryland sorghum. Zinc (Zn) should also be applied if the soil test is very low for this element. Zinc deficiency can delay sorghum maturity, possibly exposing the crop to freezing conditions before harvest.
Phosphorus, potassium and zinc are immobile nutrients and must be incorporated with tillage or placed in the soil (banded) in no-till situations. Broadcast rates of P, K and Zn can be reduced by as much as 50% if applied in a band at planting. Banding reduced rates of fertilizer helps reduce costs on dryland production. Fertilizer decisions can be delayed until subsoil conditions are ascertained at seeding, when planting equipment has the capability of banding nutrients.
Table 1. Hybrid maturity recommendations for planting dates - High Plains & Kansas
|Planting Dates - High Plains & Kansas||CRM Range|
|Mid-May to early June||112 – 118 CRM|
|Early- to late- June||106 – 112 CRM|
|Late June to early July||95 – 106 CRM|
There are 3 planting date options for sorghum. The first is mid-May to early-June, for which there are 3 planting rates and time frames:
The second planting option date, of early- to late-June, offers these strategies for planting:
The third planting date option is late June to early July, with the following planting strategies:
The recommended seeding rates can be increased 10-15% for marginal topsoil moisture at planting, cloddy seedbed, or cold soils in early no-till situations. Growers located above 4,000 feet elevation, northwest Kansas, or eastern Colorado, check with your local Pioneer Sales representative for area cutoff dates.