Sunflower Potassium Fertilizer Application Methods and Container Planting Key Points

The sunflower is a very beautiful flower. Because it grows facing the sun, it represents a positive and upward attitude toward life. During sunflower cultivation, how should potassium fertilizer be applied? What are the key points for container planting? Let us take a look together below.

I. How should potassium fertilizer be applied to sunflowers?

1. Soil conditions

In soils with relatively low available potassium content, the effect of applying potassium fertilizer is obvious, and at this time applying potassium can increase the oil content and oil yield of sunflowers. At present in China, the critical value for farmland soil potassium supply status is not a fixed value or a single line, but a range value, that is, the critical level for soil potassium supply status is set within the range of 70-100 mg/kg. For another example, in North America the critical level of available potassium for crops in northern soils is agreed to be between 40-150 mg per kg; however, in some states the recommended fertilization suggestions explicitly state that for new high-yield hybrid sunflower varieties, the critical soil potassium level must be higher than 105 mg per kg to obtain good yield. This shows that the effective application of potassium fertilizer also depends on the variety and the target yield level, and differs accordingly. In some cases, even if the soil is not deficient in potassium, applying potassium is still effective for crops.

2. Target yield level and varietal differences

When different crops are planted in the same soil, their requirements for the critical level of soil potassium supply will differ somewhat. Sunflower seeds have a very high oil content, and it is a crop with a high potassium uptake, so it has relatively high requirements for the critical level of available soil potassium. At the same time, the target yield level and differences among varieties must also be considered. For example, new high-yield hybrid sunflowers require a critical soil potassium level higher than the general index level in order to obtain good yield and give full play to the variety's potential for high yield and high oil.

3. The absence of irrigation conditions greatly affects the fertilizer efficiency of potassium fertilizer

Especially during the key growth period, ensuring irrigation can enable crops to effectively utilize potassium fertilizer. Under drought conditions, when sunflowers suffer water stress, applying potassium fertilizer is more important than applying nitrogen fertilizer. Applying potassium can improve the sunflower's use of limited water and reduce the sunflower's transpiration coefficient. Therefore, under the same drought conditions, applying potassium fertilizer helps improve the drought resistance of sunflowers.

II. What are the key points for container planting of sunflowers?

Sunflowers used for container planting have a relatively short growth period, and generally can bloom in about 50 days.

For seedling raising, plug trays and nutrient pots can be used. The seedling substrate can be prepared by mixing peat, vermiculite and sand in a ratio of 2:1:1, and a small amount of organic fertilizer can be mixed in at the same time. Container-grown sunflower seeds are relatively small, and their ability to push through the soil is relatively weak. When sowing, it should not be too deep, generally about 1 cm. After sowing, cover with soil and press lightly. If raising seedlings in winter and spring, cover with film to keep warm and shorten the emergence time. After sowing, keep the soil moist. In summer, seedlings generally emerge in 3 to 5 days, and in winter and spring they generally emerge in 5 to 10 days.

Transplanting as early as possible can shorten the seedling recovery time and also prevent the appearance of “tall-footed seedlings”. The plants can be transplanted when they grow 1 pair of true leaves. Two weeks after sowing, sunflower seedlings can grow a strong root system. The root system of sunflower seedlings is very strong, which is the basis for ensuring a relatively high transplant survival rate.

Water and fertilizer management: after planting, water should be appropriately controlled to prevent excessive vegetative growth. After budding, water appropriately according to the plant's growth condition to meet its growth needs. It is not recommended to apply base fertilizer, so as to avoid excessive fertility making the stems too thick. Topdressing can be carried out according to the plant's growth condition, or fertilizer can be applied by foliar spraying.

Pest and disease control: the incidence of pests and diseases in sunflowers is relatively low. The main diseases are bacterial leaf spot, rust, stem rot, powdery mildew and black spot; the main pests are aphids, mirids, red spiders and beetles, etc. If they occur, targeted control can be carried out.