Grain sorghum needs warm, moist soil that is well-supplied with air and fine enough to provide good seed-soil contact for rapid germination. Farmers can use a number of different tillage and planting systems to achieve these conditions. These systems may involve primary tillage, secondary tillage or no-tillage operations prior to planting.
Any seedbed preparation should provide a means of profitable crop production while minimizing soil erosion due to wind and water. Conservation tillage systems, such as reduced till, mulch till, ecofallow, strip-till, ridge-till, zero-till and no-till, provide protection from erosion. These systems also provide the added benefits of moisture, energy, labor and equipment conservation.
For successful dryland sorghum, the soil profile must have stored as much precipitation as possible. In addition, runoff from high-intensity rainfall events can be greatly reduced by maintaining residue on the soil surface. Every time the soil is tilled, some moisture is lost.
Strip-till resembles both no-till and minimum tillage systems and allows for the use of anhydrous ammonia, the least expensive nitrogen fertilizer. Small strips, generally a width of 8 inches or less, are tilled and fertilizer is applied below where the seed is planted. Strip till is more like traditional tillage, where the residue is removed and the seed is planted into a clean soil surface. However, similar to no-till, the residue between the strips remains. For dryland grain sorghum production, strip-till could be a good intermediate step for a farmer who does not want to switch to no-till.
No-till grain sorghum planting is best suited for moderately drained and well-drained soils. Many growers find it easier to plant in standing stubble rather than in stubble lying on the ground following reduced tillage. Soils often remain cooler and wetter through the growing season under no-till conditions, which is particularly true in heavy residue. While wetter soils are an advantage during dry periods, wetter soils at planting time can require that planting be delayed to allow soils to warm up, resulting in reduced yields, particularly in cool, wet springs and on poorly drained soils. Other conservation tillage systems, such as reduced till or strip-till, may be better choices in those conditions.