1. Botanical Classification
i. Botanical Name:
The botanical name of sunflower is Helianthus annuus L.
ii. Biological Classification:
2. Origin And History
Sunflower probably originated in the south-western United States, or somewhere in Mexico, where it was used in many forms. It was introduced to Europe in the 16th century and imported into Russia from Holland in the 18th century. As a cultivated plant, improved varieties were reintroduced into the USA from Russia in 1893. 3. Economic Importance
* In world, supply of sunflower seed oil is estimated as 11.7 million tons and sunflower is ranked as 6th in seed production. * According to economic survey of Pakistan sunflower is grown on 877000 ha of land. * The total amount of seeds produced was 473000 tons and the total oil produced from the sunflower crop was 179000 tons.
Sunflower is grown in rainfed as well as irrigated farming systems. Basically it grows sandy to clay soil ranging in pH from 6.5 to 7.5. The areas of adaption for this crop are in cotton belt (Vehari, Lodhran, Bahawalpur, Umerkot) and rice growing areas of Sialkot and Badin in Punjab and Sindh, respectively.
Sunflower is grown in many semi-arid regions. It is tolerant of both low and high temperatures but more tolerant to low temperatures. Optimum temperatures for growth are 21 to 75°C, but a wider range of temperatures (64 to 91°F) show little effect on productivity. Extremely high temperatures have been shown to lower oil percentage, seed fill and germination. 6.
Land Preparation/Sowing Method
* Seed bed Preparation
As sunflower has a well-developed root system, deep ploughing with a mouldboard necessary. Secondary tillage implements like a disc harrow or tines should be used to level the field for planting and subsequent irrigations. It is important that the soil around the seed remain moist during germination. With light soils the soil should be pressed during planting to make good plough is contact with seed and moist soil. This technique is quite important in dry rain fed areas. * Row To Row and Plant to Plant Distance
Sunflowers are a row crop, but the row width varies depending upon the equipment available. In irrigated areas R×R distance for sunflower crop is 75 cm and P×P distance is 23 cm, whereas; in barani areas P×P distance is given as 30cm. 7.
Time of Sowing
Sunflower is a new crop and is unlikely to complete with and replace the already established crop. However, it is highly adaptable and fits very well to the cropping system. Throughout the country sunflower is grown in two seasons: spring and summer. 8.
Generally 2-3 Kg/acre seed is recommended depending on hybrid, soil type, and availability of water and method of sowing. The seed rate of hybrids with large seed size should be more as compared to small size seeds. Seed rate is reduced to 50 % if planted with new planters. 9.
Sunflower is generally considered drought-resistant, but significant resistance in the yield has been observed due to water stress. Generally, the spring crop requires four irrigations. However for summer planting because most of the three stages tale place during the cooler months, the number of irrigations can be reduced to three. 10.
In Pakistan, most of the soils area deficient in both Nitrogen and Phosphorus and some areas are also deficient in Potash therefore, the requirement for N, P, K is given as 64.22, 56.81 and 61.75 kg/ha respectively. Optimum inputs are required for sunflower hybrids to produce their potential yields. It is therefore, recommended that 2 bags of urea and 2 bags of DAP per acre should be applied. 11(a).
i. Biennial Wormwood (Artemisia biennis)
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