B. Soil:

Sunflower will grow in a wide range of soil types from sands to clays. The demands of a sunflower crop on soil macronutrients are not as great as corn, wheat or potato. As with other non-leguminous grain crops, nitrogen is usually the first limiting factor for yield. Medium to high levels of macronutrients are usually required for good plant growth. Sunflower stover contains a large proportion of these elements, which means sunflower is relatively inefficient in the use of these elements. However, most of these nutrients are returned to the soil with the stover.

Sunflower is low in salt tolerance but is somewhat better than fieldbean or soybean in this respect. Corn, wheat, rye and sorghum are rated medium, and sugarbeet and barley are high in salt tolerance.

Good soil drainage is required for sunflower production, but this crop does not differ substantially from other field crops in flooding tolerance.

V. Cultural Practices: a. Seedbed Preparation:

Many different tillage systems can be used effectively for sunflower production. Conventional systems of seedbed preparation consist of moldboard plowing or chisel plowing to invert residue and several secondary field operations. Conventional systems have been shown to increase the availability and improve the distribution of potassium and nitrogen and to increase the seed zone temperatures. However, the risk of erosion and expense of the several tillage operations has led to greater interest in minimum or ridge tillage systems.

B. Seeding Date:

Sunflower can be planted at a wide range of dates, as most cultivars are earlier in maturity than the length of growing season in most areas. In areas of the world with no winters, sunflower has been planted at any month of the year to obtain satisfactory yields. In northern regions, highest yields and oil percentages are obtained by planting early - as soon after the spring-sown small grain crops as possible.

A later planting date tends to increase the proportion of linoleic acid in sunflower, especially at southern locations. Damage of sunflower heads by insect larvae may be increased by early planting. Test weight tends to decrease with late plantings.

C. Method and Rate of Seeding:

A planting depth of 1 to 3.5 in. allows sunflower seeds to reach available moisture and gives satisfactory stands. Deeper plantings have resulted in reduced stands and yields. If crusting or packing of the soil is expected, with silt loam or clay soils, a shallower planting depth is recommended.

Sunflower row spacing is most often determined by machinery available, which might be 30 or 36 in. for corn, soybean or sorghum growers, or narrower rows for sugarbeet growers. Hence, row spacings can be chosen to fit available equipment. Row spacings of 30 in. are most common. There is evidence that earlier, semidwarf varieties may perform better in narrower rows at high populations.

Plant population has a strong effect on seed size, head size, and percent oil. A medium to high population produces higher oil percentage than does low populations, and the smaller heads dry down faster at higher plant populations.

A lower plant population is critical for maximizing seed size for non-oilseed use.